Merkel cell carcinoma: treatment and outcomes over a 10-year period at a high-volume academic center

Merkel cell carcinoma (MCC) is a rare, highly aggressive malignancy which lacks high-level evidence-based treatment guidelines.

To determine outcomes of MCC patients and assess the role of radiation in treatment, we performed a retrospective chart review of patients treated for MCC between 2006 and 2016 at a single high-volume academic medical center. The primary outcome was overall survival (OS) for the entire population and for those populations receiving specific therapies.

Forty-two patients were evaluable. OS for all patients was not reached since most remain alive at time of analysis. OS for the American Joint Committee on Cancer (AJCC) stage I was not reached. OS for stages II, III, and IV was 37.3 months (6.8, -), 49.5 months (14.2, 49.5), and 14.5 months (10.8, -), respectively. OS could not be reached in the high radiotherapy (RT) dose group (biologically equivalent dose [BED] ≥ 60) and was 49.5 months (10.8, -) in the low-dose group (BED < 60). For surgical margin status, OS was 14.9158 months (6.8008, -) for positive margins and 37.3 months (10.8, -) for negative margins.

No conclusive findings for OS were identified; however, trends for improved OS were associated with lower AJCC staging, negative surgical margins, and high RT doses.