Grading in Myxofibrosarcoma of the Extremities Can Predict Survival and Local Control

Background: The aim of this retrospective analysis is to understand the natural history of myxofibrosarcoma (MFS), in particular whether the prognosis can be influenced by histologic grade. Methods: We reviewed 229 adult patients with primary MFS of the limbs. We analyzed disease-specific survival (overall survival [OS]) and local recurrence (LR). Results: Median age was 70 years (range, 19-92). Sixteen (7.0%) were grade 1, 38 (16.6%) grade 2, and 175 (76.4%) grade 3. A worse OS was found in grade 3 MFS (73.1%) than in grade 2 and 1 MFS (91.9 and 100%, respectively) at 5 years (p = 0.031). Locally recurred MFS had a worse OS (p = 0.018). A better LR-free rate (100% at 5 years) was observed in grade 1 MFS; however, a similar rate was observed between grade 2 and 3 tumors (77.1 and 80.0% at 5 years, respectively, p = 0.412). Conclusions: Grade 3 MFS has the worst prognosis. Grade 1 MFS have the lowest risk of LR. These data could help identify a high-risk patient group, thus selecting a more careful follow-up for higher-risk patients. Since MFS mostly affects the elderly population, it might be useful to reserve adjuvant treatments (radiotherapy and chemotherapy) to higher-risk patients.