Narrow resection margins not linked to mortality, recurrence in Merkel cell carcinoma

Excision with narrow margins does not predict mortality or recurrence in patients with Merkel cell carcinoma, results of a study have shown. Residual tumour, found primarily on deep surgical margins, is independently associated with prognosis.

“Wide local excision constitutes the standard of care for Merkel cell carcinoma, but the optimal margin width remains controversial,” the investigators said.

To assess whether narrow margins (0.5–1 cm) were associated with outcome, the investigators recruited 214 patients from a retrospective French multicentric cohort and had had excision of primary tumour with minimum lateral margins of 0.5 cm. Multivariate regression was used to assess factors associated with mortality and recurrence.

Of the patients, 58 (27.1 percent) had undergone excision with narrow margins (0.5–1 cm) relative to 156 (72.9 percent) with wide margins (>1 cm). Cancer-specific survival was similar between patients with narrow margins and those with wide margins during a median follow-up of 50.7 months (5-year specific survival rate: 76.8 percent, 95 percent confidence interval [CI], 61.7–91.9 percent vs 76.2 percent, 95 percent CI, 68.8–83.6 percent, respectively).

In addition, no significant between-group differences were observed in overall survival, any recurrence-free survival, and local recurrence-free survival.

Of note, cancer-specific mortality correlated with age, male sex, American Joint Committee of Cancer stage III, and presence of positive margins.

The study was limited by its retrospective design and the heterogeneous baseline characteristics between groups.