• BACKGROUND
    • Primary tumor resection is the mainstay of treatment for undifferentiated pleomorphic sarcoma (UPS); however, the necessity of adjuvant chemotherapy has been debated. We aimed to clarify the effect of adjuvant chemotherapy on survival rates in patients with UPS with localized and resectable primary lesions.
  • METHODS
    • This retrospective analysis included data of 2112 patients with localized UPS arising in the extremities and trunk, extracted from a registry in Japan. We estimated overall survival (OS), identified prognostic factors, and adjusted patient characteristics in the two groups treated with or without chemotherapy using propensity score matching (PSM).
  • RESULTS
    • The 5-year OS rate was 79.4%. In multivariate OS analysis, adjuvant chemotherapy was a good prognostic factor (hazard ratio 0.65; 95% confidence interval 0.48-0.9, P = 0.009). Large tumor size was the poorest prognostic factor, and OS decreased with the tumor size (P < 0.0001). In all patients, adjuvant chemotherapy prolonged OS (5-year OS: 82.3% vs. 78.6%, P = 0.03). Adjuvant chemotherapy did not affect OS in patients with tumor size < 5 cm; the benefit was strong in patients with tumor size 10 to < 15 cm (5-year OS: 79.5% vs. 66.8%, P = 0.003). Adjuvant chemotherapy efficacy was not pronounced in patients with tumor size 5 to < 10 cm (5-year OS: 87% vs. 80%, P = 0.06) and ≥ 15 cm (5-year OS: 60.7% vs. 49.5%, P = 0.08). After PSM, adjuvant chemotherapy was significantly associated with improved OS (P = 0.02).
  • CONCLUSIONS
    • In patients with localized UPS, adjuvant chemotherapy tended to improve OS when tumors were ≥ 5 cm, especially when they were 10 to < 15 cm.