Delayed Treatment Associated With Worse Survival in High-grade Undifferentiated Pleomorphic Sarcoma

Time to treatment initiation is linked to survival in several malignancies. However, its role in soft tissue sarcomas, particularly high-grade, undifferentiated pleomorphic sarcoma, remains unclear. Evaluation of individual histologic subtypes enables a more patient-centered treatment approach. The purpose of this study was to evaluate the association between time to treatment initiation and survival in patients with high-grade, localized undifferentiated pleomorphic sarcoma.

Patients diagnosed with localized, high-grade undifferentiated pleomorphic sarcoma between 2004 and 2021 were identified retrospectively from the National Cancer Database. After excluding noneligible cases, 6220 patients were included. Kaplan-Meier and multivariable Cox proportional hazards models were used to evaluate the association between time to treatment initiation and overall survival.

Treatment initiation after 4 weeks was associated with significantly lower 5-year survival (P < 0.001). On multivariable analysis of extremity and trunk tumors, prolonged time to treatment initiation was independently associated with worse survival (hazard ratio [HR] = 1.01 per week; 95% confidence interval (CI) = 1.00-1.03; P = 0.013). However, this association was not observed in tumors of the head and neck (HR = 1.00; 95% CI = 0.95-1.05; P = 0.837) or abdomen and pelvis (HR = 1.00; 95% CI = 0.97-1.03; P = 0.995).

Prolonged time-to-treatment initiation is independently associated with decreased survival in patients with localized, high-grade undifferentiated pleomorphic sarcoma of the extremity and trunk. The time-to-treatment initiation appears to be increasing over time, which may be driven by evolving diagnostic practices and insurance-related delays.