Is Wide Re-Excision Required For Incompletely Resected Dermatofibrosarcoma Protuberans? A 20-Year Multicentric Experience

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue sarcoma. The treatment of localized disease is excision with clear surgical margins. The aim of the study was to define the role of further wide re-excision surgery after initial positive margins resection.METHODS: Eighty-five patients diagnosed with DFSP were collected from prospectively maintained databases of 2 orthopedic oncology reference centers. The whole cohort of patients underwent wide local excision (minimum margin 2 cm). Further resections were planned in case of contaminated margins. The type of biopsy, surgical margins, the number and time to local recurrence and the indication for adjuvant radiotherapy were evaluated. Statistical analysis was performed using chi(2) tests and odds ratio (OR) with 95% confidence intervals (CI).RESULTS: Sixty-three patients underwent surgery, mean follow-up 83 months (range 9-190). Extremities were involved 29 times, trunk 25, pelvis 8, head 1. Tumors were low (N.=50), intermediate (N.=12), and one high grade sarcomas. Fibrosarcomatous transformation (FS-DFSP) was noted in 24% cases. Fifty-one patients (81%) underwent inadvertent excision prior to referral to reference center. In total, 63 patients underwent surgery 80 times; 50 patients (79%) had only one resection. Patients with previous inadvertent excision did not have higher intralesional rates on definitive surgery (20% vs. 29%, OR=0.61, P>0.05), presented no higher local recurrence rates (6% vs. 8%, OR=0.70, P>0.05) following re-excision, but 32% of them required plastic surgery similarly to those referred to hospitals for biopsy (29%, OR=1.16, P>0.05). Five patients (8%) with FS-DFSP received local RT (one with palliative intent).CONCLUSIONS: DFSP commonly presents with prior inadvertent excision to tertiary referral in 2 different countries; using a well-defined surgical approach aiming for a minimum resection margin of 2 cm and a standardized radiotherapy protocol, a low number of local recurrences was obtained. An increasing rate of plastic reconstructions was needed for second treatments.