Background: Despite optimal surgical therapy for patients with dermatofibrosarcoma protuberans (DFSP), some patients still continue to develop local recurrence. The authors' objective was to identify and analyze clinicopathologic factors for disease free survival in a large group of patients who were followed prospectively at a single institution.
Methods: Prospectively collected data and pathology slides were available for review from 159 patients with primary or recurrent DFSP who underwent treatment between July 1950 and July 1998. The study group was comprised of patients with either the "classic" form of DFSP or the fibrosarcomatous "high grade" variant of DFSP (FS-DFSP). Patient, tumor, pathologic, and treatment factors were analyzed using the log rank test for univariate influence and Cox regression analysis for multivariate influence. Local recurrence free survival was determined by the Kaplan-Meier actuarial method.
Results: Of the 159 patients who comprised the current study group, 134 (84%) had the classic form of DFSP. The FS-DFSP variant was found in the remaining 25 patients (16%). The overall 5-year local recurrence free survival rate was 75%, with a median follow-up of 4. 75 years. The 5-year recurrence free survival rate for each group was 81% and 28%, respectively. On univariate analysis, age > 50 years, very close (< 1 mm) to positive microscopic margins, FS-DFSP variant, high mitotic rate, and increased cellularity were unfavorable prognostic factors. Multivariate analysis determined very close (< 1 mm) to positive microscopic margins and FS-DFSP variant to be independent adverse prognostic factors. For the 34 patients who developed a recurrence after surgical resection (21%), the median time to local recurrence was 32 months. Of the patients in this group, two died from metastatic disease.
Conclusions: The prognosis after surgical resection with negative and sometimes positive microscopic margins for patients with DFSP is very good. However, increased age, high mitotic index, and increased cellularity are predictors of poor clinical outcome. The FS-DFSP variant represents a much more aggressive tumor with metastatic potential. Patients who are treated with curative intent for FS-DFSP should undergo aggressive attempts at complete surgical resection. Patients with recurrent classic DFSP without evidence of adverse prognostic features may benefit from conservative management, especially in the setting of potentially unresectable disease.
Copyright 2000 American Cancer Society.