Dermatofibrosarcoma protuberans: long-term outcomes of 53 patients treated with conservative surgery and radiation therapy.

Purpose: To evaluate outcomes of conservative surgery and radiation therapy (RT) treatment in patients with dermatofibrosarcoma protuberans.

Methods And Materials: We retrospectively reviewed the medical records of 53 consecutive dermatofibrosarcoma protuberans patients treated with surgery and preoperative or postoperative radiation therapy between 1972 and 2010. Median tumor size was 4 cm (range, 1-25 cm). Seven patients (13%) were treated with preoperative RT (50-50.4 Gy) and 46 patients (87%) with postoperative RT (60-66 Gy). Of the 46 patients receiving postoperative radiation, 3 (7%) had gross disease, 14 (30%) positive margins, 26 (57%) negative margins, and 3 (7%) uncertain margin status. Radiation dose ranged from 50 to 66 Gy (median dose, 60 Gy).

Results: At a median follow-up time of 6.5 years (range, 0.5 months-23.5 years), 2 patients (4%) had disease recurrence, and 3 patients (6%) had died. Actuarial overall survival was 98% at both 5 and 10 years. Local control was 98% and 93% at 5 and 10 years, respectively. Disease-free survival was 98% and 93% at 5 and 10 years, respectively. The presence of fibrosarcomatous change was not associated with increased risk of local or distant relapse (P=.43). One of the patients with a local recurrence had gross residual disease at the time of RT and despite RT to 65 Gy developed both an in-field recurrence and a nodal and distant recurrence 3 months after RT. The other patient with local recurrence was found to have in-field recurrence 10 years after initial treatment. Thirteen percent of patients had an RT complication at 5 and 10 years, and 9% had a moderate or severe complication at 5 and 10 years.

Conclusions: Dermatofibrosarcoma protuberans is a radioresponsive disease with excellent local control after conservative surgery and radiation therapy. Adjuvant RT should be considered for patients with large or recurrent tumors or when attempts at wide surgical margins would result in significant morbidity.