Prognostic factors and outcomes of patients with myxofibrosarcoma

Myxofibrosarcomas (MFS) are a historically heterogeneous group of tumors that exhibit a propensity for local recurrence. The objectives of this study were to analyze the prognostic factors and outcomes of patients with MFS treated at a single institution.

We retrospectively reviewed the records of 69 consecutive patients with pathologically confirmed MFS of the extremities or superficial trunk who underwent surgery from August 1995 to November 2010. Clinicopathologic features, treatments, and patient outcomes were reviewed.

Sixty-nine patients were identified, of whom 38 were men (55%). The median age was 62 years. Sixty-four patients (93%) presented with primary tumors, and 5 patients (7%) presented with locally recurrent tumors. Median tumor size was 6.0 cm, and 44 patients (64%) had grade 3 tumors (FNCLCC [Fédération Nationale des Centres de Lutte Contre le Cancer] classification). Margins were microscopically positive in 14 patients (20%) and negative in 55 patients (80%), including close margins (<1 mm) in 14 patients (20%). Fifty-three patients (77%) received radiotherapy. At a median follow-up of 41 months, there were 11 local (16%) and 11 distant (16%) recurrences. The local and distant 5-year recurrence-free survival rates were 72% and 82%, and the 5-year overall survival was 61%. Increased age (scaled by 0.1; hazard ratio [HR] 1.80, P=0.002) and tumor size (HR 1.12, P=0.004) were negatively correlated with overall survival. Positive/close (<1 mm) margin status (HR 4.34, P=0.030) predicted worsened local recurrence-free survival.

MFS exhibit a propensity for local recurrence, which is predicted by resection with positive or close margins. Aggressive surgery combined with radiotherapy may contribute to more effective local control.