Adjuvant radiation and survival following surgical resection of sinonasal melanoma.

BACKGROUND: Surgery remains the mainstay of treatment for sinonasal melanoma, but it is often difficult to obtain clear, negative margins. Therefore, patients often receive adjuvant radiation therapy (RT), however its impact on overall survival (OS) is not well understood.

METHODS: Patients with surgically resected sinonasal melanoma were identified from the National Cancer Data Base (NCDB, n=696). Kaplan-Meier curves and parametric survival regression were used to analyze the impact of adjuvant RT on OS from surgery. Adjusted time ratios (aTRs) were computed, with values >1 corresponding to improved survival.

RESULTS: 399 (57.3%) patients received adjuvant RT. Those receiving RT tended to be younger but with more advanced disease and greater likelihood of positive margins, compared to those receiving no adjuvant therapy. Median survival was 25.0months for those treated with surgery alone, compared to 28.3months for those receiving adjuvant RT (log-rank P=0.408). When adjusting for potential confounders, there was a trend towards greater survival with adjuvant RT (aTR 1.16, 95%CI 0.98-1.37). RT appeared beneficial in those with stage IVB disease (aTR 2.58, 95%CI 1.40-4.75) but not stage IVA (aTR 1.19, 95%CI 0.88-1.61) or III (aTR 0.85, 95%CI 0.65-1.13) disease. In contrast, there were no differences in impact of RT according to margin status (aTR 1.16 for both positive and negative margins).

CONCLUSIONS: Adjuvant therapy does not appear to provide a significant survival benefit in resected sinonasal melanomas regardless of margin status, except those with stage IVB disease. Practitioners should carefully consider the added benefit of adjuvant therapy in these patients.