Citation Nr: 0211086 Decision Date: 09/03/02 Archive Date: 09/09/02 DOCKET NO. 98-06 780 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in Phoenix, Arizona THE ISSUE Service connection for primary sclerosing cholangitis, claimed as secondary to radiation exposure. REPRESENTATION Appellant represented by: Mark R. Lippman, Attorney at Law WITNESS AT HEARING ON APPEAL Appellant ATTORNEY FOR THE BOARD Vito A. Clementi, Counsel INTRODUCTION The appellant had active duty from February 1960 to February 1962. This matter was last before the Board of Veterans' Appeals (Board) in January 2000, on appeal from a rating decision of the Phoenix, Arizona, Department of Veterans Affairs (VA) Regional Office (RO). Upon its last review, the Board reopened the appellant's previously denied claim for service connection, which had been denied in August 1994 and not appealed, and upon the reopened claim denied the benefit sought. The appellant sought review of the Board's decision before the U.S. Court of Appeals for Veterans Claims (Court). By decision dated September 12, 2000 and pursuant to the parties' joint motion, the Court vacated the Board's decision to the extent that it had denied service connection for the disorder at issue on the merits, and remanded the claim for readjudication. Accordingly, the Board's determination in January 2000 that the claim was reopened remains the law of the case. Having reviewed the claim in its entirety, the Board is of the opinion that this matter is ready for appellate review. FINDINGS OF FACT 1. Primary scloerosing cholangitis (PSC) was not shown in active service. 2. The weight of the informed medical evidence indicates that PSC, shown years after service, is not related to any incident of military service or to any service-connected disorder. CONCLUSION OF LAW PSC, claimed as secondary to radiation exposure, was not incurred in or aggravated by active service, nor may PSC be presumed to have been incurred therein. 38 U.S.C.A. §§ 1101, 1112, 1113, 1131, 5107(a) (West 1991 & Supp. 2001); 38 C.F.R. §§ 3.303(d), 3.307, 3.309, 3.311 (2001). REASONS AND BASES FOR FINDINGS AND CONCLUSION Preliminary Matter: VA's Duty to Notify and Assist There has been a significant change in the law during the pendency of this appeal. The Veterans Claims Assistance Act of 2000 (VCAA), Pub. L. No. 106-475, 114 Stat. 2096 (2000), now codified at 38 U.S.C.A. §§ 5100, 5102, 5103, 5103A, 5107 (West Supp. 2001). The legislation has eliminated the well- grounded claim requirement, has expanded the duty of VA to notify the appellant and the representative, and has enhanced its duty to assist an appellant in developing the information and evidence necessary to substantiate a claim. See generally VCAA. VA issued regulations to implement the VCAA in August 2001. 66 Fed. Reg. 45,620 (Aug. 29, 2001) (to be codified as amended at 38 C.F.R. §§ 3.102, 3.156(a), 3.159 and 3.326(a)). The amendments were effective November 9, 2000, except for the amendment to 38 C.F.R. § 3.156(a) that is effective August 29, 2001. Except for the amendment to 38 C.F.R. § 3.156(a), the second sentence of 38 C.F.R. § 3.159(c), and 38 C.F.R. § 3.159(c)(4)(iii), VA stated that "the provisions of this rule merely implement the VCAA and do not provide any rights other than those provided in the VCAA." 66 Fed. Reg. 45,629. Accordingly, in general where the record demonstrates that the statutory mandates have been satisfied, the regulatory provisions likewise are satisfied. The United States Court of Appeals for Veterans Claim (Court) held in Holliday v. Principi, 14 Vet. App. 280 (2001) that the VCAA was potentially applicable to all claims pending on the date of enactment, citing Karnas v. Derwinski, 1 Vet. App. 308 (1991). Subsequently, however, the United States Court of Appeals for the Federal Circuit held that Section 3A of the VCAA (covering the duty to notify and duty to assist provisions of the VCAA) was not retroactively applicable to decisions of the Board entered before the effective date of the VCAA (Nov. 9, 2000). Bernklau v. Principi, No. 00-7122 (Fed. Cir. May 20, 2002); See also Dyment v. Principi, No. 00-7075 (Fed. Cir. April 24, 2002). In reaching this determination, the Federal Circuit appears to reason that the VCAA may not apply to claims or appeals pending on the date of enactment of the VCAA. However, the Federal Circuit stated that it was not reaching that question. The Board notes that VAOPGCPREC 11-2000 (Nov. 27, 2000) appears to hold that the VCAA is retroactively applicable to claims pending on the date of enactment. Further, the regulations issued to implement the VCAA are to be applicable to "any claim for benefits received by VA on or after November 9, 2000, the VCAA's enactment date, as well as to any claim filed before that date but not decided by VA as of that date." 66 Fed. Reg. 45,629 (Aug. 29, 2001). Precedent opinions of the chief legal officer of the Department and regulations of the Department are binding on the Board. 38 U.S.C.A. § 7104(c) (West 1991). For purposes of this determination, the Board will assume that the VCAA is applicable to claims or appeals pending on the date of enactment of the VCAA. The VCAA provides that VA shall make reasonable efforts to assist a claimant in obtaining evidence necessary to substantiate the claimant's claim for a benefit under a law administered by the Secretary, unless no reasonable possibility exists that such assistance would aid in substantiating the claim. In part, the VCAA specifically provides that VA is required to make reasonable efforts to obtain relevant governmental and private records that the claimant adequately identifies to VA and authorizes VA to obtain. The VCAA further provides that the assistance provided by the Secretary shall include providing a medical examination or obtaining a medical opinion when such an examination or opinion is necessary, as further defined by statute, to make a decision on the claim. 38 U.S.C.A. § 5103A (West Supp. 2001). The Board has carefully considered the evidence of record and is of the opinion that the provisions of the VCAA have been satisfied. First, although the Board's January 2000 decision was vacated to the extent that it denied entitlement to service connection for the disorder in question, it nonetheless remains a matter of record. The decision details the evidence of record, and provided the appellant with a discussion of why the Board then found the claim was not substantiated. That decision further highlighted that the veteran must come forward with competent medical evidence of a nexus between current disorders and his period of service. That the appellant was aware of such deficiencies, and sought to remedy them, cannot be doubted. Through counsel he sought to supplement the record by the proffering of another expert medical opinion prior to the Board's current review. Further, the appellant has been continually apprised of the evidence of record and VA's efforts to assist him in substantiating the claim through Statements of the Cases issued during the pendency of the appeal, as well as the Board's decision of January 2000 and the subsequent notification provided by the Board concerning the additional independent medical opinion. The claimant has been ably assisted by counsel towards substantiating the claim and completing the record. He has waived the right to have his additional medical opinion reviewed by the RO. Finally, the appellant's claim has been subjected to numerous VA medical inquiries, as well as the obtaining of two independent medical opinions. There appears to be no further existing evidence which would substantiate the claim, (i.e., no further advisement is necessary or warranted to the appellant with respect to evidence towards substantiation) and the claim is ready for appellate review. The Merits of the Claim The appellant contends that PSC is the result of in-service radiological treatment that he was afforded for the treatment of acne. Having carefully considered all of the evidence of record, the Board is of the opinion that the preponderance of the evidence is against the claim and the appeal will be denied. By law, the Board's statement of reasons and bases for its findings and conclusions on all material facts and law presented on the record must be sufficient to enable the claimant to understand the precise basis for the Board's decision, as well as to facilitate review of the decision by courts of competent appellate jurisdiction. The Board must also consider and discuss all applicable statutory and regulatory law, as well as the controlling decisions of the appellate courts. See Vargas-Gonzalez v. West, 12 Vet. App. 321, 328 (1999); Gilbert v. Derwinski, 1 Vet. App. 49, 56-57 (1990); 38 U.S.C.A. § 7104(d)(1) (West 1991). Toward these ends, and without reliance for the dispositive findings in this matter, the Board first observes that a layman's reference guide explains that PSC is "inflammation and eventual scarring and obstruction of the bile ducts inside and outside the liver." The Merck Manual of Medical Information, 570, Home Edition 1997. This matter has been remanded in part to enable the Board to reexamine the evidence of record and articulate a more comprehensive statement of reasons and bases. To the extent that this decision reiterates factual summaries previously considered by the Board, it is emphasized that such repetition only represents those matters that have remained unchanged by the Court's remand directives and the evidence subsequently developed. Fletcher v. Derwinski, 1 Vet. App. 394, 397 (1991) [in proceeding with a decision on the merits of an appellant's claim subsequent to remand, the Board is to fully readjudicate the issue on appeal in accordance with Court's directives, and such is not "merely for the purposes of rewriting the opinion so that it will superficially comply with the 'reasons or bases' requirement of 38 U.S.C. § 7104(d)(1). A [Court] remand is meant to entail a critical examination of the justification for the decision."]. In general, service connection may be granted for disability or injury incurred in or aggravated by active military service. 38 U.S.C.A. §§ 1110, 1131. The resolution of this issue must be considered on the basis of the places, types and circumstances of his service as shown by service records, the official history of each organization in which the claimant served, his medical records and all pertinent medical and lay evidence. Determinations relative to service connection will be based on review of the entire evidence of record. 38 C.F.R. § 3.303(a). As a general matter, service connection for a disability on the basis of the merits of such claim is focused upon (1) the existence of a current disability; (2) the existence of the disease or injury in service, and; (3) a relationship or nexus between the current disability and any injury or disease during service. See Cuevas v. Principi, 3 Vet. App. 542 (1992); Rabideau v. Derwinski, 2 Vet. App. 141 (1992). Secondary service connection shall be awarded when a disability is "proximately due to or the result of a service-connected disease or injury. . . ." 38 C.F.R. § 3.310(a). See Libertine v. Brown, 9 Vet. App. 521, 522 (1996); Harder v. Brown, 5 Vet. App. 183, 187 (1993). In this matter, the critical issue or determinative question involves the interpretation of the appellant's medical history: whether the in-service radiation treatment, either by itself or as a result of diseases or disorders caused by it, ultimately resulted in the appellant being diagnosed to have PSC. It is the Board's fundamental responsibility to evaluate the probative value of all medical and lay evidence of record. See Owens v. Brown, 7 Vet. App. 429 (1995); Gabrielson v. Brown, 7 Vet. App. 36 (1994); see also Guerrieri v. Brown, 4 Vet. App. 467, 470-471 (1993) [observing that the evaluation of medical evidence involves inquiry into, inter alia, the medical expert's personal examination of the patient, the physician's knowledge and skill in analyzing the data, and the medical conclusion that the physician reaches]. In light of this inquiry, the Board will first review the appellant's pertinent medical history. The Board will then proceed to evaluate the various medical opinions of record in its analysis of the claim. The Medical Evidence: The record indicates that while on active duty in March 1960, the appellant sought medical treatment for severe acne vulgaris of the back. The appellant was afforded radiological therapy and several chronological medical entries reflect continued diagnoses of severe acne vulgaris and resulting lesions. In May 1961, the appellant again complained of persistent acne of the back, and it was noted that he had had Kynex, radiological, and "usual" therapy, and that he would be placed on antogenous vaccine. Thereafter, service records do not mention any additional radiological therapy to the appellant's back and there is no indication as to the dose of radiation the appellant sustained in the earlier therapy sessions, nor evidence of any gastrointestinal or other sequallae (e.g., burns, nausea, etc.). In February 1962, the appellant underwent VA medical examinations in connection with a then pending claim for service connection for acne. In the context of a special VA dermatological examination, the appellant reported that while in service, he received a great deal of treatment for his acne, including what the examiner characterized as including "considerable" radiological treatment. A June 1962 rating decision denied service connection for acne on the basis that the appellant had acne prior to service, and that its progression in service had not been shown to be any more than would have occurred in the normal course of the disease. A VA hospital summary for the period of June to August 1967 reflects that the appellant reported a history of having a right kidney stone removed in March 1967, and that one week prior to this admission, he again experienced hematuria and dull right costovertebral angle tenderness and ache. Examination at the time of admission was found to be entirely normal except for a scar on the right flank. An intravenous pyelogram (IVP) was interpreted to reveal a stone in the left lower pole, right lower pole, of the right ureter with delay of function and then pointing of the stone on the right. Calcium and phosphorus studies revealed elevated calcium and lowered phosphorus levels repeatedly. In June 1967, the appellant underwent a right ureterolithotomy and pelviotomy with "T" Tube intubation of the upper ureter, and in July 1967, the tube was removed. In August 1967, the appellant was found to have developed a right-side parathyroid adenoma. It was noted that laboratory reports had detected continued elevated calcium and lowered phosphorus levels. After surgical removal of the adenoma, a renal stone was determined to have moved down into his ureter, and with treatment the stone was passed spontaneously. It was believed that the appellant had developed a post-calculous pyelonephritis and antibiotics were continued. Thereafter, the appellant's condition gradually improved. The diagnoses included hyperthyroidism, right ureteral and right renal stones, left renal stones, parathyroid adenoma, and atrophy of another parathyroid gland. It was noted in a VA hospital summary from May 1969 that following the excision of a parathyroid tumor from near the lower pole of the thyroid gland on the right extending to the mediastinum, the appellant passed several calculi. At that time, the appellant reported that an IVP revealed new calculi on the left, and that in August 1968, another IVP revealed negative findings. Since that time, the appellant reported recurrent intermittent right flank pain with recurrent hematuria. An IVP in May 1969 revealed a left upper pole renal calculus but otherwise negative findings. VA hospital records from October 1979 reveal that the appellant underwent the excision of two sebaceous cysts on the upper back which were reportedly recurrent and examples of severe acne of the upper back status post multiple radiation treatments to the area. The operative record indicates that the appellant's skin was noted to be very fibrotic and avascular, possibly secondary to radiation. A VA hospital summary for the period of October to November 1988 reflects that the appellant was admitted with a two week history of increasing epigastric pain, progressive jaundice, darkening of urine, a 22-pound weight loss over the previous six months, and marginal fevers with chills. The abdomen was diffusely tender with right upper quadrant guarding but no peritoneal signs. On October 18, 1988, the appellant underwent a surgical cholecystectomy, intraoperative cholangiogram, common duct resection, Roux-Y hepaticojejunostomy, and liver biopsy. A U-tube was placed percutaneously through the liver, exiting through the left hepatic duct entering the jejunal loop and exiting several centimeters distal to the anastomosis and exiting percutaneously. A JP tube was placed at the juncture of the superior surface of the liver and the U-tube. The appellant was discharged with the U-tube in place. The appellant was diagnosed to have nephrolithiasis, secondary to hypercalcemia. It was also noted that the appellant had sclerosing cholangitis, borderline hypertension, status post resection of the parathyroid adenoma, 16 years earlier. VA medical records for the period of October 1988 to December 1992 reflect continued treatment for post-surgical residuals and for primary sclerosing cholangitis. The appellant first sought service connection for primary sclerosing cholangitis in December 1992. The appellant maintained that the condition was caused by radiation exposure that he had sustained while receiving therapy for his acne while in service. He reported that he received radiation two to three times a week for two and a half months, and that his entire torso - from the neck to the thighs, was exposed to the treatments. He added that it was in March 1967 that he started demonstrating symptoms which he believed were related to the over exposure of radiation, consisting of renal calculi for which he had surgery at that time and again in June 1967. In August 1967, he had exploratory surgery for a hyperparathyroid, which he argued was clearly related to radiation exposure. In support of his December 1992 claim, the appellant also provided copies of various articles that he believed supported his claim that his PSC was related to his radiation exposure during service. The articles addressed the management of gastrointestinal injury associated with acute radiation syndrome, the relationship between hypercalcemia and bile flow and biliary calcium secretion, therapeutic radiation and hyperthyroidism, fundamentals of radiobiology, an overview of the biological effects of ionizing radiation, and the effects of exposure to low levels of ionizing radiation. Upon VA radiological consultation in January 1994, it was noted that service medical records provided no evidence as to the amount or duration of any in-service radiological treatment. The radiological examiner indicated that review of the medical record revealed two statements taken from the appellant in 1960 of having received radiation therapy to his back for acne over a two to three month period. However, nowhere in the chart, other than by the appellant's statement, was there documentation of such therapy. From this basis and relying on the appellant's statements, the examiner believed that it was not readily apparent how much radiation therapy both in terms of dosages and frequency, the appellant had received. This examiner was referring the claim to the radiation physicist who he believed to be the most appropriate individual to evaluate the issue of radiation induced pathology. The January 1994 VA medical physicist reviewed the appellant's file in order to find evidence of the relationship between radiation therapy doses and his claimed conditions. However, the examiner noted that it was very important to have the exact radiation dosages and the frequencies of such therapies. From the information of record, the examiner was unable to ascertain the dosage sustained by the appellant, and he reported that it was difficult for him to establish a relationship between the radiation therapy and the claimed condition. Upon VA gastroenterological consultation in July 1994, the examiner commented that there was no evidence to suggest that radiological therapy could cause PSC, and that the cause of the disorder was unknown. In December 1996, and in connection with the appellant's then-pending claim of service connection for parathyroid adenoma and renal calculi, a physician with the office of VA's Chief Public Health and Environmental Hazards Officer, concurred in the report of the Chief, Radiation Oncology Service, Mountain Home VA Medical Center, who commented that the literature showed that as little as 32 ionizing radiation units (RADS) to the parathyroid could cause adenomas as early as within three years. Therefore, it was the physicians' joint opinion that even though the total dose and the exact location of radiation were not available from the records, it was likely that the radiation was the cause of the parathyroid in the appellant. The record indicates that by rating decision dated in December 1996, service connection for the adenoma and its complications to include kidney stones was granted. The appellant testified before the undersigned at a personal hearing conducted at the RO in January 1999. In substance relevant to this appeal, the appellant reiterated that he had in-service radiological therapy for acne on his back during service in 1960, which lasted over a two-week period at the rate of every two days, and the process was repeated over another two-week period. He stated that sclerosing cholangitis first manifested itself in severe form in 1988. He added that he began to have parathyroid problems in 1967. The appellant indicated that he had not been given more than two cycles of radiation treatments. The appellant also maintained that the development of fibrotic tissue in the area of the radiation treatments was evidence that he had received excessive radiation. The Medical Opinion Evidence: In a series of two December 1998 letters submitted in support of the reopened claim, Michael R. Gray, M.D., M.P.H., stated that "there was no way of disproving" that the appellant was overdosed with radiation in service, and that the overdose led to the development of a fibrotic skin condition and the parathyroid adenoma and all of its sequelae, including PSC. In substance, Dr. Gray observed in his first letter: 1. "Considerable" radiological treatment was given during the appellant's military service, (referencing the special VA dermatological examination of March 1962); 2. Although no records were maintained detailing the specific doses the appellant received, "the history [Dr. Gray] obtained indicates that [the appellant] received 12 x-ray treatments in two separate course of therapy," and that "the intensity of the dose was sufficient to have actually caused first and second degree burns to the [appellant's] back, neck and shoulders," and; 3. The appellant had experienced medical problems which were, to a reasonable medical certainty, causally related to such treatment and that VA had "confirmed and endorsed" that the appellant had had excised a parathyroid adenoma, which in turn had been "causally related to radiation in the general area of the body" of the thymus and thyroid, and from which the appellant had developed biliary lithiasis and renal lithiasis, and; 4. Sclerosing cholangitis was to a reasonable medical certainty a consequence of radiation therapy he had received while in service similar to hyperparathyroidism, and; 5. The causal links described were "well within the range of reasonable medical certainty." In an addendum also dated in December 1998, Dr. Gray noted that an August 1989 article relative to therapeutic radiation and hyperparathyroidism (Archives of Internal Medicine, Volume 149, "Therapeutic Radiation and Hyperparathyroidism") "clearly established that the association between primary hyperparathyroidism and prior therapeutic radiation exposure was confirmed." He also observed that in 1991, a research article reported that in cases of radiation to the skin involving significant deep penetrating radiation, "a very hard, wood-like plaque up to three centimeters thick was palpable" in the skin areas affected, and that the appellant had been observed to have had tissue that was extremely fibrotic at the time a sebaceous cyst was removed. Thus, according to Dr. Gray, it could be assumed that the appellant did receive significantly high doses of radiation, which resulted in a parathyroid adenoma, which in turn resulted in renal and biliary lithiasis, which led to sclerosing cholangitis. In July 1999, the Board caused the appellant's claims folder to be reviewed by an independent medical expert to determine the medical probability that there was a causal relationship between the appellant's PSC and exposure to radiation during service. The expert was also requested to render an opinion as to the degree of medical probability that there was a causal relationship between the appellant's parathyroid adenoma and/or renal calculi and the appellant's development of PSC. By letter dated in September 1999, Thomas J. McGarrity, M.D., a Professor of Medicine at the Gastroenterology and Hepatology Department at the Hershey Medical Center in Hershey, Pennsylvania rendered his opinion. He reported that in addition to reviewing the appellant's history, he had consulted textbooks on Gastroenterology, Hepatology, General Medicine, and Endocrinology, as well as conducted a "MEDLINE" computer research inquiry on "the association of sclerosing cholangitis and radiation exposure." In substance, Dr. McCarrity observed: 1. The etiology of PSC was unknown, but was believed to have an immunologic basis; 2. The relationship between hyperparathyroidism and biliary tract disease, including gallstones, was "debatable," and that hyperparathyroidism was not mentioned as a risk factor in any of the reviewed textbooks, although there were reports of both positive and negative association between hyperparathyroidism and gallstone disease; 3. Although Dr. Gray had observed that hypercalcemia can cause biliary tract disease by increasing bile lithogenicity and that there was "some experimental evidence" to support this proposition, the medical correction of the appellant's hypercalcemia and hyperparathyroidism had occurred approximately 20 years before the onset of liver disease; 4. He (Dr. McGarrity) was "skeptical" of the proffered etiologic link between the corrected hyperparathyroidism/hypercalcemia and the appellant's sclerosing cholangitis, as the cause of the latter disorder was unknown and he could find no information in the literature or through computerized research on such a linkage, and that the linkage between sclerosing cholangitis and radiation enteritis had not been established; 5. Specifically with regard to the appellant, if he had been treated with a deeply penetrating form of radiation therapy which could have accounted for his liver disease, symptoms of acute radiation sickness would have been expected which were not apparent on review of the appellant's records. Dr. McGarrity opined that a causal relationship between the appellant's parathyroid adenoma and hypercalcemia and his later development of primary sclerosing cholangitis 20 years later was "remote." In June 2001, the appellant submitted a medical opinion authored by Craig N. Bash, M.D., accompanied by a waiver of RO consideration. See 38 C.F.R. § 20.1304(c). Dr. Bash reported that he had conducted a personal interview with the appellant, and that he had reviewed the procedural evidence of record, "x-ray reports," "laboratory reports," the submitted opinions from Drs. Gray and McGarrity and that he conducted a review of unspecified "medical literature." In substance, Dr. Bash observed: 1. The appellant had a service induced parathyroid adenoma, caused by in-service radiation therapy, and that it was "known that parathyroid adenomas cause hypercalcemia;" 2. A medical textbook noted that nephrolithiasis was not specifically associated with hyperparathyroidism but was "most common in this setting," thus causing Dr. Bash to conclude that it was "clear that [the appellant's] hyperparathyroidism secondary to radiation likely caused his nephrolithiasis;" 3. From Dr. Bash's review of the record, it appeared that in late 1988, the appellant had experienced gallstones, which would have produced an obstruction that would have in turn produced a bacterial infection leading to cholangitis. Due to the conflicting medical opinions of record, the Board again caused the appellant's claims folder to be reviewed by an independent medical expert. In May 2002, John R. Lake, M.D., Professor of Medicine and Surgery and Director of the Gastroenterology, Hepatology and Nutrition Division at the University of Minnesota Medical School rendered his opinion that the appellant's PSC was not related to his radiation therapy. In his report, Dr. Lake noted that he had 16 years experience as a practicing hepatologist, and that he had participated in the care of approximately 300 patients with PSC. In substance, Dr. Lake observed: 1. He questioned, yet assumed to be true, that the appellant's parathyroid adenoma and hypercalcemia for which service connection had been granted were related to his in-service radiation therapy, although the medical basis for such a conclusion was "weak." 2. The cause of PSC was unknown, but there was a strong association of PSC to other autoimmune diseases, particularity ulcerative colitis and a number of other secondary causes, which were unrelated to this matter. However, he stated that gallstones were not a cause of PSC, and although such could cause bile duct obstruction, gallstones did not produce "stricturing of the intra- and extrahepatic bile ducts," termed by Dr. Lake to be "the hallmark of primary sclerosing cholangitis." 3. It was important to not confuse cholangitis secondary to bile duct obstruction (which was generally caused by bacterial inflammation of the bile ducts) with sclerosing cholangitis as the appellant had, (which was believed to be an autoimmune phenomenon) as they were two distinct entities. As to the other medical opinions of record, Dr. Lake's report includes the following observations: 1. Apparently in reference to report of Dr. Michael Gray, dated December 28, 1998, who had opined that the appellant's radiation therapy led to subsequent biliary lithiasis, which in turn had led to the primary sclerosing cholangitis, this thesis (termed as a "cascade" by Dr. Lake) was insupportable based upon medical fact. 2. Dr. Lake noted that there was little data to suggest that hyperparathyroidism was associated with an increased risk of gallstones as maintained by Dr. Gray, and that although previous experts quoted 1994 research in support thereof, the research article only demonstrated that the biliary system was permeable to calcium ions, and that serum calcium concentration could be one determinant of biliary calcium concentration. Dr. Lake explained that although the researchers thus demonstrated that those with hypercalcemia had a greater prevalence of calcified gallstones, an increased serum level was not a cause of gallstones, but only that when such gallstones were present they were likely to be calcified. 3. Even with "several erroneous assumptions," because the appellant's hyperparathyroidism and hypercalcemia occurred 20 years before he was diagnosed to have liver disease, it would remain highly unlikely that the hyperthyroidism and hypercalcemia were related 4. With apparent reference to the report of Dr. Craig N. Bash, Dr. Lake observed that the former's observation that hypercalcemia might have contributed to pancreatitis, which in turn led to sclerosing cholangitis, was erroneous. Dr. Lake pointed out that the appellant had never been diagnosed to have an episode of pancreatitis. Dr. Lake concluded by opining that there was little evidence to support "the chain of events" that were proffered by the appellant to link his in-service radiation therapy to a diagnosis of PSC - there was no evidence to suggest that radiation therapy led to hypercalcemia, and there was "absolutely no evidence" that gallstones led to PSC. Analysis: The determinative question in this case involves the probability of medical causation. Only parties possessing medical expertise may address competently such a question. The Board in this matter is presented with primarily four expert opinions: two in support of the appellant's claimed theory of entitlement, and two essentially against the claim. As was previously noted, it is the Board's primary role in this circumstance to weigh such evidence and ascertain its probative value. From the outset, it should be noted that the evaluation of such evidence does not involve a mere numeric tabulation of those opinions favoring viz. those against the claim. It is the whole of each underlying opinion that must be examined, both by itself and in conjunction with other evidence. Guerreri, supra.; see also Wray v. Brown, 7 Vet. App. 488, 492-493 (1995) (Observing that in cases involving multiple medical opinions, each should be examined, analyzed and discussed for corroborative value, and should not be dismissed as merely "cumulative."). Having examined the medical opinions and the evidence of record, the Board has concluded that the weight of the informed medical evidence is clearly against the claim. Essentially, the preponderance of the competent evidence indicates that the theory of entitlement propounded by the appellant (1) is not generally accepted in the medical community, and that (2) to the extent that medical opinion evidence supports the claim, it is outweighed by more competent evidence or is flawed in its factual basis. The Board does not seek relevant expert opinion gauged to a medical certainty. Instead, it seeks to ascertain whether, on examination of all the evidence, there is "an approximate balance of positive and negative evidence regarding the merits of an issue material to the determination of the matter," which, under the "benefit-of-the-doubt" rule, inures to the benefit of the claimant and mandates that the claim be granted. Ashley v. Brown, 6 Vet. App. 52, 59 (1993); see also Massey v. Brown, 7 Vet. App. 204, 206-207 (1994). With this preface, the Board first observes that among much important information imparted to this inquiry, Dr. Lake's May 2002 report sets out a highly relevant definition. This matter involves inquiry into the cause of primary scloerosing cholangitis, not cholangitis. It appears in this regard that both Dr. Gray and Dr. Bash did not set forth their understanding of the critical distinction. It is to be noted as well that in his opinion, Dr. McGarrity appears to have discussed and analyzed the evidence of record as to PSC. Thus, both Dr. Lake and Dr. McGarrity set forth the specific and apparently correct diagnostic entity for consideration, (i.e., that the appellant has primary scloerosing cholangitis and there does not appear to be any evidence of any other specified type). Leaving aside the question of whether the opinions of both Dr. Gray and Dr. Bash are thus wholly flawed due to their failure to properly identify the disease in question, which in itself renders them without probative value, the Board will nonetheless continue to examine the evidence of record. The Board next turns to the question of whether generally accepted medical opinion supports the finding that radiation caused parathyroid adenoma, or hypercalcemia or gallstones, and whether the radiation, any of these disorders either singularly or in combination caused PSC. The Board is guided in this respect by four relevant inquiries: (1) Whether the theory can be (or has been) tested, (2) whether the theory has been subjected to peer review and publication, (3) whether the known or potential rate of error has been considered, and (4) to what extent the theory is accepted in the relevant scientific community. Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 113 S. Ct. 2786, 2796-97 (1993), quoted in Rucker v. Brown, 10 Vet. App. 67, 73 (1997). The Board observes that the although the Daubert decision was quoted in a discussion of whether a claim was well grounded under the then-applicable law, the Court then pointed out that in a merits adjudication, the evidence need only reach equipoise in order for the claim to be granted, as is noted by the Board above. Rucker at 73. Here, it does not appear to be disputed that the medical community holds the cause of PSC to remain unknown. Although both Drs. McGarrity and Lake have so reported, the opinions of Drs. Bash and Gray have constructed theories as to how the appellant's in-service radiation led to the diagnosed disorder. From this, the Board concludes that the scientific community has not accepted the essential premise that a cause of the disorder can be identified. The fourth prong of the Daubert inquiry is thus answered in the negative, and because both Dr. Bash and Dr. Gray have set forth a chain of reasoning to their conclusions, prongs 1, 2, and 3 of the Daubert inquiry is similarly answered in the negative. In other words, there is no information proffered that indicates that a theory exists in the medical community supporting the linkage between radiation therapy and PSC, such theory having been tested, subjected to peer review and publication, or whether the known or potential rate of error has been considered. Remaining is the question as to what weight should be assigned the medical opinions, either in isolation or in combination with each other. The Court has held in this regard that where an appellant provides more than one medical opinion in support of a claim for service connection, the additional medical opinions are to be examined for corroborating, rather than merely cumulative, evidence. Wray, 7 Vet. App. at 492; cf. Paller v. Principi, 3 Vet. App. 535, 538 (1992). With regard to Dr. Gray's December 1998 opinion, in particular that as set forth in his addendum, the physician's entire opinion appears to be premised upon medical studies indicating a linkage between cholangitis (and not primary sclerosing cholangitis) and the assertedly antecedent disorders. This is evidenced by Dr. Gray's observation that significantly high doses of radiation led to parathyroid adenoma, which in turn resulted in renal and libliary lithiasis. However, as is noted above, Dr. Lake has set forth that cholangitis with its associated renal dysfunction is not the appellant's disability, as stated by Dr. Gray. (See Dr. Gray's addendum, third paragraph). Dr. Gray's opinion is otherwise prefaced upon the assumption of the misidentified disorder. Moreover, as was noted by Dr. Lake, PSC was not associated with gallstones, as such did not produce stricturing of the hepatic bile ducts. As for Dr. Bash's opinion, the Board first observes (as did Dr. Lake, and possibly Dr. Bash himself as evidenced by the comment in his report "[a] note to [the veteran's attorney] where is the pancreatitis"), that there is no evidence the appellant had pancreatitis. Further, Dr. Bash's preliminary conclusion that it was "clear that [the appellant's] hyperparathyroidism secondary to radiation likely caused his nephrolithiasis" is not supported by a plain English reading of that portion of the quoted textbook. While the Board's examination of the medical text in question confirms the accuracy of Dr. Bash's cited portion, the Board's reading that nephrolithiasis not being specifically associated with hyperparathyroidism does not support a causal linkage, although hyperparathyroidism was "common in this setting." In other words, a plain English reading of the quoted portion suggests that evidence of a causal linkage between nephrolithiasis and hyperparathyroidism is not established. In these circumstances, the Board is of the opinion that the clear preponderance of the informed medical evidence is against the claim. Although it is not dispositive in and of itself, Dr. Lake's May 2002 report details in depth the evidence of record; analyzes previous opinions of record and sets forth the state of medical knowledge as to the etiology of the appellant's disorder. The Board finds it highly probative that Dr. Lake is a professor of medicine at a major university, who in addition to being aware of the state-of- the-art relevant medicine due to his professorial duties, is also a practitioner who was involved in the care of approximately 300 patients with PSC. His explanation, in light of all other evidence of record, convinces the Board that the appellant's in-service radiological treatment, as well what Dr. Lake has termed to be the chain of causal events advanced by the appellant to explain his disorder, is not supportable. ORDER The appeal is denied. Richard B. Frank Member, Board of Veterans' Appeals IMPORTANT NOTICE: We have attached a VA Form 4597 that tells you what steps you can take if you disagree with our decision. We are in the process of updating the form to reflect changes in the law effective on December 27, 2001. See the Veterans Education and Benefits Expansion Act of 2001, Pub. L. No. 107-103, 115 Stat. 976 (2001). In the meanwhile, please note these important corrections to the advice in the form: ? These changes apply to the section entitled "Appeal to the United States Court of Appeals for Veterans Claims." (1) A "Notice of Disagreement filed on or after November 18, 1988" is no longer required to appeal to the Court. (2) You are no longer required to file a copy of your Notice of Appeal with VA's General Counsel. ? In the section entitled "Representation before VA," filing a "Notice of Disagreement with respect to the claim on or after November 18, 1988" is no longer a condition for an attorney-at-law or a VA accredited agent to charge you a fee for representing you.