Radiotherapy alone in patients with Merkel cell carcinoma: the Westmead Hospital experience of 41 patients.

OBJECTIVES

To review the role of radiotherapy as treatment (RTx) alone in patients with Merkel cell carcinoma (MCC).

METHODS

Data on 41 patients with MCC treated with RTx alone between 1993 and 2013 at Westmead Hospital, Sydney, were reviewed and analysed.

RESULTS

The patients' median age was 80 (range 45-96 years) among 18 (44%) women and 23 (56%) men. All but one patient were white and six (15%) were immunosuppressed. Most (59%) were irradiated at initial diagnosis with the remainder treated in the relapse setting. The median duration of follow up was 39 months. Head and neck was the most frequently treated site (63%). The median lesion size was 30 mm (range 5-130 mm). The in-field control rate was 85%. Most out-of-field relapses were to visceral organs. Overall survival at 5 years was 40%.

CONCLUSIONS

Patients with MCC treated with RTx alone experience a high likelihood of obtaining in-field disease control. Doses of 50-55 Gy in 20-25 fractions are recommended but lower doses (25 Gy in five fractions) are still effective. A minority will be cured with many patients subsequently dying of systemic relapse.