Paradoxical Improvement in Malignant Pleural Mesothelioma Outcomes Following Delayed Treatment Initiation

Time to treatment initiation (TTI) has been identified as a predictor of survival in many cancers, but its impact on malignant pleural mesothelioma (MPM) is unknown. This study investigates factors influencing TTI in MPM and its association with overall survival.

The Surveillance, Epidemiology, and End Results (SEER) database was used to obtain data for MPM patients in the United States. TTI was defined as the number of days from diagnosis to initiation of first treatment, and delayed TTI was defined as exceeding the median TTI. Χ² tests and t-tests compared sociodemographic and clinical differences between early and delayed TTI groups, while Kaplan-Meier and Cox proportional hazards models evaluated relationships between prognostic factors, TTI, and survival.

Among 4879 MPM patients, the median TTI was 39 days. Median survival was 10 months among early TTI patients and 13 months among delayed TTI patients. Patients with epithelioid histology were more likely to have delayed TTI, as were patients who received combination therapy or were diagnosed more recently (p < 0.0001). Adjusting for covariates, delayed TTI status remained associated with better survival (HR 0.79, 95% CI: 0.74-0.84).

This study presents an important insight into the management of MPM, demonstrating that delayed time to treatment initiation is positively associated with improved overall survival, contrary to findings in most cancers. This finding underscores the importance of comprehensive, multidisciplinary care, as delays due to robust staging evaluations and patient travel to high-volume centers of excellence likely contribute to delays in treatment. Taken together, these results suggest that clinicians should prioritize personalized treatment planning and collaborative care over a push to rapidly initiate treatment to optimize patient outcomes in MPM.