Radiotherapy alone for primary Merkel cell carcinoma

Merkel cell carcinoma is a rare and potentially aggressive cancer of the skin. Cumulative data from small retrospective series have supported treatment by wide excision and adjuvant radiotherapy. However, wide excision may be difficult to perform in patients with tumors of the head and neck or in older populations with comorbidities that may be incompatible with general anesthesia.

Nine patients (group 1) with stage I (without lymph node involvement) Merkel cell carcinoma primary tumors were treated in our center by radiotherapy alone. The rate of recurrence was compared between this group and 17 additional patients (group 2) with stage I Merkel cell carcinoma who received conventional treatment (surgery followed by radiotherapy).

The median follow-up was 3.0 years (range, 8 months to 7 years) for group 1 and 4.6 years (range, 5 months to 11 years) for group 2. During this period, we observed 1 relapse and 1 progression of disease in group 2. No statistical difference was found in overall and disease-free survival between the 2 groups of patients.

This study demonstrates the possibility of treating inoperable Merkel cell carcinoma by radiotherapy alone, with outcomes similar to those of classic treatment.