Radiation in management of patients with dermatofibrosarcoma protuberans

The preferred treatment of dermatofibrosarcoma protuberans (DFSP) is wide resection, namely, margins > or = 3 cm beyond the evident disease and histologically negative margins. We assess the success achieved by radiation combined with surgery for positive/close margins or by radiation alone for those tumors that are not resectable for technical/medical reasons. The literature on this point is virtually nonexistent.

The outcome of treatment of 18 patients with DFSP by radiation alone (n = 3) and radiation and surgery (n = 15) at the Massachusetts General Hospital was assessed. All of the lesions at the time of the treatment by radiation alone or combined with surgery were less than 10 cm. This was the maximum dimension. The actual tumor volume was much less than indicated by this maximum dimension, as the tumors were usually relatively flat.

The 10-year actuarial local control rate was determined to be 88%. Local control was realized in the three patients treated by radiation alone, with follow-up periods of > or = 9 years. Among 15 patients treated by radiation and surgery, there have been three local failures; the 10-year actuarial local control rate was 84%. The three local failures occurred in 12 patients whose surgical margins were positive. One of these three local failures developed in the group of two patients whose lesions were scored as grade II.

Radiation in well-tolerated dose schedules is an effective option in the management of patients with DFSP. This appears to be true for radiation alone or postoperatively for margin-positive disease (primary or recurrent).