Dermatofibrosarcoma protuberans (DFSP): Mohs surgery technique and prognostic factors

Abstract

9066 Background: DFSP is a rare type of soft-tissue tumor accounting for 1,4% of all sarcomas with high propensity to recur locally. Wide local excision is the standard treatment with 15–60% local failure. Mohs surgery technique allows adequate margin control in all directions, appropriate to recurrences or tumors located in difficult areas to achieve free margins; it is not the standard procedure in DFSP that involves the underlying fascia or sites where preservation of normal tissue is not required. The objective is to report the outcome of patients (pts) surgically treated in one institution and to evaluate prognostic factors. Material and methods: we assessed retrospectively a cohort of pts with histological diagnosis of DFSP. Demographic data, tumor features and surgical procedure (Mohs excisions) were evaluated. Uni-multivariable statistical analysis were performed to determine prognostic factors in terms of local failure. Results: 30 pts have been evaluated (period 1998–2003). Pts characteristics: median age: 41 (17–62); male/female: 13/17; localization: trunk 15 (50%), head and neck 5 (17%), extremities 7 (23%), abdomen 3 pts; median size: 3,5 cm (1,5–12) and less than 3 mitoses/HPF was seen in 20 pts; 3 DFSP were classified as fibrosarcomatous. Surgery characteristics: wide local resections: 12 pts; Mohs technique: 9 pts (4 were recurrences) and 9 pts were admitted for reexcision (previous surgery in another institution), median clear margins were 2, 2.5 and 2 cm, respectively. 11/30 pts were operated by oncologist surgeons; median follow up:22 months (1–174); 5 pts (16,6%). developed local recurrences. There were not relapses in pts with Mohs procedure. The only statistical significant prognostic factor to local recurrence was fibrosarcomatous histology ( 2/3 relapsed). No distant or lymph nodes recurrence was seen. Conclusion: local recurrence of DFSP is the main problem. Multidisciplinary and expertise medical and surgical oncologists have to decide the type of surgical procedure and have to consider that a biological feature (fibrosarcomatous histology) is one of the most relevant prognostic factor to local recurrences after the hand of the surgeon. No significant financial relationships to disclose.