Real-world outcomes for patients with pleural mesothelioma: A multisite retrospective cohort study

Aim: To evaluate the real-world treatment patterns and outcomes for patients with pleural mesothelioma (PM) in the era of immunotherapy.

Methods: This retrospective audit included patients with PM diagnosed within three tertiary referral centers in Queensland, Australia from January 2017 to July 2023. Patient and treatment characteristics and outcomes were recorded. Data was analyzed using descriptive statistics and the Kaplan-Meier survival method.

Results: A total of 90 patients were included: 84% were male, the median age was 75 years (range 70-79) and 85% had baseline Eastern Group Cooperative Group of 0-1. Subtypes included 54% epithelioid, 17% biphasic, 12% sarcomatoid, and 17% unspecified/unknown. First-line treatment was received by 57/90 patients (63%) and 33/90 patients (37%) received the best supportive care (BSC). Chemotherapy was most used (63%) overall, but first-line immunotherapy was more commonly used since ipilimumab/nivolumab was reimbursed by the Australian Pharmaceutical Benefits Scheme in July 2021. After first-line treatment, only 40% received second-line treatment and 60% received BSC. 12-month overall survival (OS) and progression-free survival for all patients were 53% (95% confidence interval [CI]: 43-65) and 25% (95% CI 15-40) respectively. 12-month OS was 72%, 64%, and 29% for immunotherapy, chemotherapy, and BSC, respectively. There was no significant difference in survival between chemotherapy and immunotherapy (hazard ratio 1.28, 95% CI: 0.65-2.5, p = 0.5).

Conclusion: In our unselected real-world cohort, both chemotherapy and immunotherapy are active against PM, but the prognosis remains guarded. There remains a need for better treatment options, especially in the first-line setting. Enrolment in clinical trials is crucial to improving outcomes in this debilitating disease.