Don't underestimate full excision biopsy

Harrison Hot Springs, British Columbia - The importance of a full-thickness excision biopsy should never be underestimated due to the complete message it can deliver regarding the risk of local recurrence and regional metastases for both patients and their surgeons, according to David R. Byrd, M.D.

"In the five state area we serve, 10 to 20 percent of the referral patients I see have a positive deep margin on their pathology review for a deep-shave biopsy, therefore we're talking to a patient with an arm tied behind our backs," says Dr. Byrd, professor and director, Melanoma Center, University of Washington Medical Center, Seattle. "If it's already intermediate thickness, that's really not going to change the recommendation for the width of excision or a sentinel lymph node dissection (SLND), but with the thin (tumors) it's particularly limiting in terms of knowing it would be optimal to recommend a wide excision alone."

Backing SLND

While the study has only released preliminary results, the findings state that sentinel node status is the most important prognostic factor in early-stage melanoma, and lymphatic mapping and sentinel node biopsy allows early and accurate detection of occult nodal metastases.

Disease-free and melanoma-specific survival rates are significantly higher after immediate complete lymph node dissection for occult nodal metastases than delayed complete lymph node dissection for clinical nodal recurrence. Lymphatic mapping/sentinel node biopsy should become standard for staging and assessment of prognosis in primary melanoma, and for identifying patients who may benefit from immediate complete lymph node dissection, according to the MSLT-1 results released at the 2005 American Society of Clinical Oncology meeting (D. L. Morton, J. F. Thompson, A. J. Cochran, R. Essner, R. Elashoff, Multicenter Selective Lymphadenectomy Trial Group).

"This is the only randomized-prospective trial looking at survival with SLND," Dr. Byrd said here at the 72^nd Annual Pacific Northwest Dermatological Society meeting. "My personal opinion is that it is likely to benefit a subset of patients perhaps with microscopic disease that would not have been found for a long time. If not for sentinel node, by the time it turns up as a grossly positive node they're well on the way to metastatic disease."

The clear-cut payoff from SLND is the staging or prognosis information, clearly telling patients where they stand with their disease with a false-negative rate of 5 percent, according to Dr. Byrd.

"In the end, finding positive or negative nodes translates into survival, Dr. Byrd says. "There is no doubt in my mind that there is a peace-of-mind advantage of doing SLND over not completing one - it's not a morbid procedure. The biggest payoff of determining the nodal status will be when we get an effective adjuvant treatment."

In terms of overall survival and incidence rates of local recurrence, thickness and ulceration of the tumor have shown to play a predominant role. While a recent multi-institutional study that involved 93 surgeons practicing in four countries reviewing 740 patients found that those patients who had a more radical 4 cm radial margin of excision did not have any lower rate of recurrence compared with those who had a narrower 2 cm margin, the impact of local recurrence in each group signified shorter survival (Annals of Surgical Oncology, 8(2); 101-108, C. M. Balch, et. al.).

"This study is the best data regarding the link of survival and local recurrence," Dr. Byrd tells Dermatology Times. "Of course, this could be a circular discussion: did they die because they had a local recurrence, or was a local recurrence a reflection of a bad biology tumor?"