Local Relapse and Survival Outcomes in Patients with Scalp Sarcoma: A Retrospective Study of 95 Patients Treated in a Provincial Cancer Care Institution Over 25 Years

Objectives There is limited literature on the optimal treatment of sarcoma arising in the scalp. This study evaluates local relapse (LR) and survival outcomes of patients with scalp sarcoma treated at a provincial cancer care institution. Methods A retrospective review of 95 patients with a primary diagnosis of scalp sarcoma referred from 1990-2015 was completed. Kaplan-Meier statistics were used to estimate LR-free survival (LRFS) and overall survival (OS). Survival curves were compared using log-rank tests. Regression analyses were performed using Cox proportional hazards model. Results The median age at diagnosis was 77 years. The most common histologies were angiosarcoma (27%), undifferentiated pleomorphic sarcoma (24%), and pleomorphic dermal sarcoma (21%). Final margins were 36% positive, 28% close, 31% negative, and 5% unknown. Of 73 patients treated with curative-intent, 32 (44%) experienced LR. Five-year LRFS was 56.0% and overall survival was 48.3%. Patients with close or positive margins who received pre- or post-operative radiotherapy (n=19) had similar LR risk compared to patients who did not (n=34) (five-year LRFS 41.8% vs 69.1%; p=0.145). On multivariate analysis, angiosarcoma was associated with a higher LR risk (Hazard ratio (HR) 12.06, p<0.001). The use of radiotherapy showed a trend towards reduced LR risk but did not reach statistical significance (HR 0.37, p=0.066). Conclusions Patients with scalp sarcoma have high risk of LR, particularly in cases with positive margins. Adjuvant radiation was not associated with improved local control for close or positive margins. Complete surgical excision to establish negative margins remains the primary standard treatment for patients with this rare disease.