PHOENIX — Cutting through a melanoma during a shave biopsy may make reaching an accurate prognosis more difficult, but it probably won't harm the patient, Dr. Darrell Rigel said at a clinical dermatology conference sponsored by Medicis.
Dr. Rigel of New York University Medical Center, New York, said that two recently published studies addressed the concern that cutting through certain cancers during a biopsy can disperse tumor cells and worsen prognosis. Both of the studies compared excisional with incisional biopsies.
In the first study, researchers from Carolinas Medical Center in Charlotte, N.C., reported that 22% of shave biopsies had positive deep margins (Ann. Surg. Oncol. 2007; 14:893–8). In the second study, researchers from the Free University Hospital, Amsterdam, found that incisional biopsies did not have a negative impact on survival (Ann. Surg. Oncol. 2007;14:1424–30).
In the first study, Dr. Richard L. White Jr. and his colleagues analyzed pathology reports from Jan. 1, 2004, through June 30, 2005, for 223 cases of primary melanoma. The sample comprised 51 excisional biopsies, 44 punch biopsies, and 128 shave biopsies. Of the specimens analyzed, 167 were from thin melanomas (1 mm or less).
Only 16% of excisional biopsies had positive margins. Just 2% were positive deep margins, and none were found in specimens from the thin melanomas. Punch biopsy specimens also had no positive deep margins in the thinner melanomas. Positive margins were more common overall (68%), but were mostly wide margins attributable to the punch technique. Only 7% of punch biopsies had positive deep margins.
Half of all shave biopsies produced positive margins, including the 22% that had positive deep margins. The analysis revealed positive deep margins for 17% of the thinner melanomas sampled by the shave technique. Shave biopsy was most commonly done for thinner melanomas. It also produced samples that were significantly thinner. Of 56 specimens, the average biopsy thickness was 1.41 mm with the shave technique, 3.58 mm with the punch method, and 3.19 mm for excisional biopsies.
In the second study, Dr. Paul A.M. van Leeuwen and his colleagues in the Netherlands prospectively studied 471 patients diagnosed with stage I or II melanoma after partial removal of a skin lesion. Most of the patients had a superficial spreading melanoma (65%) or a nodular melanoma (26.7%). Average follow-up was 5 years or more. The investigators divided the population by biopsy type: wide excision biopsy (279 patients), narrow excision biopsy (109), excision biopsy with positive margins (52), and incision biopsy (31). Biopsy type did not prove to be significant in univariate or multivariate analyses of disease-free survival or overall survival. The presence of residual tumor cells in reexcision specimens for 41 patients also was not significant.