Factors influencing radiation treatment recommendations in early-stage Merkel cell carcinoma: a survey of US-based radiation oncologists

Background: It is unclear which subgroups of Merkel cell carcinoma (MCC) patients benefit the most from radiation. We surveyed radiation oncologists (RO) that regularly see and treat MCC to understand how they approach the treatment of early-stage MCC. Methods: A web-based survey was emailed to 63 ROs, who were identified through publications, guideline panel membership, and/or affiliation with institutions of high MCC volume. ROs provided treatment recommendations for two hypothetical case scenarios of early stage MCC. Results: Among 28 respondents (45%), 26 regularly saw and treated MCC patients for a median 7 years (range, 0–30). While all ROs recommended adjuvant radiation for a stage II upper extremity MCC, only 48% recommended adjuvant radiation for stage I head and neck MCC. Conclusion: Among US-based MCC RO ‘specialists,’ there is equipoise on the role of radiotherapy for stage I MCC. Ideally, prospective studies are needed to identify which patients may benefit from radiation.