Oncological efficiency of wide local excision in dermatofibrosarcoma protuberans

Abstract

Background: Dermatofibrosarcoma protuberans (DFSP) is a slow-growing, low- to intermediate-grade malignant sarcoma. Its optimal treatment is resection with wide margins; the likelihood of local control associated with this procedure exceeds 90%. The probability of regional or distant metastases is <5%.

Objective: We examined the clinical, epidemiological, and pathological features, the treatment types, and outcomes of patients to investigate the width of safe surgical margins (SM) and how the width of SMs affected recurrence in DFSP.

Methods: We retrospectively examined the records of 60 patients who were initially operated on with wide local excision for DFSP in the period 2008-2019. Optimal cutoff points for SMs were calculated with the receiver operating characteristic curve analysis and found as 1.925 cm histopathologically and 2.26 cm macroscopically.

Results: During the mean 89.6-month follow-up, local recurrence was seen in 36.7% and distant metastasis in 20% of the patients. Recurrences were significantly related to peripheral resection margins. Analysis by histopathologic cutoff points showed that the local recurrence rate was 84% when SM was ≤1.925 cm, but only 2.85% when >1.925 cm (p = 0.002). Recurrence-free survival was 40.92 months when SM was ≤1.925 cm and 225.75 months when s >1.925 cm (p<0.001). Analysis by macroscopic cutoff points showed that the local recurrence rate was 95.5% when SM was ≤2.26 cm, but only 4% when >2.26 cm (p = 0.001). Recurrence-free survival was 43 months when SM was ≤2.26 cm and 222 months when >2.26 cm (p<0.001). In metastatic patients, progression-free survival was 9 months with cytotoxic chemotherapy, whereas 38.4 months with tyrosine kinase inhibitor (imatinib) (p = 0.002).

Conclusion: This study showed SMs >2.5 cm to be sufficiently safe for WLE and optimized the balance among safe margin width, reconstruction need, and surgical morbidity. In metastatic DFSP patients, tyrosine kinase inhibitor imatinib is more effective than cytotoxic chemotherapy for progression-free survival.

Keywords: Dermatofibrosarcoma protuberans; Histopathologic margins; Oncology; Recurrence; Wide local excision.