Dermatofibrosarcoma protuberans - A clinicopathologic analysis of patientstreated and followed at a single institution

BACKGROUND. Despite optimal surgical therapy for patients with dermatofibro sarcoma protuberans (DFSP), some patients still continue to develop local r ecurrence. The authors' objective was to identify and analyze clinicopathol ogic factors for disease free survival in a large group of patients who wer e followed prospectively at a single institution. METHODS. Prospectively collected data and pathology slides were available f or review from 159 patients with primary or recurrent DFSP who underwent tr eatment between July 1950 and July 1998. The study group was comprised of p atients with either the "classic" form of DFSP or the fibrosarcomatous "hig h grade" Variant of DFSP (FS-DFSP). Patient, tumor, pathologic, and treatme nt factors were analyzed using the log rank test for univariate influence a nd Cox regression analysis for multivariate influence. Local recurrence fre e 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 remai ning 25 patients (16%). The overall 5-year local recurrence free survival r ate was 75% with a median follow-up of 4.75 years. The 5-year recurrence fr ee survival rate for each group was 81% and 28%, respectively. On univariat e analysis, age > 50 years, very close (< 1 mm) to positive microscopic mar gins, FS-DFSP variant, high mitotic rate, and increased cellularity were un favorable prognostic factors. Multivariate analysis determined very close ( < 1 mm) to positive microscopic margins and FS-DFSP Variant to be independe nt adverse prognostic factors. For the 34 patients who developed a recurren ce after surgical resection (21%) the median time to local recurrence was 3 2 months. Of the patients in this group, two died from metastatic disease. CONCLUSIONS, The prognosis after surgical resection with negative;and somet imes positive microscopic margins for patients with DFSP is Very good. Howe ver, increased age, high mitotic index, and increased cellularity are predi ctors of por clinical outcome. The FS-DFSP variant represents a much more a ggressive tumor with metastatic potential. Patients who are treated with cu rative intent for FS-DFSP should undergo aggressive attempts at complete su rgical resection. Patients with recurrent classic DFSP without evidence of adverse prognostic features may benefit from conservative management, espec ially in the setting of potentially unresectable disease. (C) 2000 American Cancer Society.