Residual melanoma after an excisional biopsy is an independent prognostic factor for local recurrence and overall survival

The aim of this study was to evaluate the effect of a residual melanoma after an excisional biopsy on prognosis of patients with cutaneous melanoma.

Between 2000 and 2007 sentinel lymph node biopsy with wide reexcision of a primary melanoma site was successfully performed in 692 patients (315 male and 377 female; mean age 55.7 years) at the Institute of Oncology Ljubljana, Slovenia. Clinicopathological data of all patients were extracted from a prospective institutional melanoma database and the frequency of local recurrences and survival were compared between patients with residual melanoma and those without it. For a statistical analysis univariate and multivariate analyses were used.

Only 25 (3.6%) patients had a residual melanoma. There was no difference in mean tumor thickness (3.9 and 2.8 mm) and ulceration (40% and 34%) of the primary melanoma between patients with and without residual melanoma. However, a number of local recurrences (16% versus 2.7%) and a number of metastases in sentinel lymph nodes (44% versus 22%) were significantly higher and a 5-year survival was significantly lower (64% versus 87.5%) in patients with residual melanoma. Breslow thickness, ulceration, positive SLNB and residual melanoma were independent prognostic factors for overall survival.

Residual melanoma is very rare after an excisional biopsy of the primary melanoma. However, when present it indicates a higher probability of local recurrence and a worse overall survival.