Treatment patterns and outcomes for patients with malignant pleural mesothelioma in England in 2013-2017: A nationwide CAS registry analysis from the I-O Optimise initiative

Objectives: Malignant pleural mesothelioma (MPM) is a rare and aggressive cancer with a poor prognosis and limited treatment options. This study assessed the characteristics, treatment patterns, and outcomes for patients diagnosed with MPM in England.

Materials and methods: As part of I-O Optimise, this retrospective cohort study analyzed data recorded in the Cancer Analysis System in England for all adult patients newly diagnosed with MPM between 2013 and 2017, with follow-up to March 2018 or death, whichever occurred first. Overall survival (OS) was estimated using Kaplan-Meier methods. A Cox regression model was used to describe the impact of sociodemographic and clinical characteristics at diagnosis on OS.

Results: 9458 patients diagnosed with MPM were analyzed. Median age at diagnosis was 75 years; 83.4% were male. Eastern Cooperative Oncology Group performance status (ECOG PS) was 0-1 for 44.5%; 2 for 11.5%; >2 for 9.1%; and missing for 34.9% of patients. TNM stage was missing for 60.4%. A majority of patients had epithelioid histology (36.4%) or not otherwise specified (NOS) MPM (43.3%). After diagnosis, 48.7% of all patients received best supportive care (BSC; no surgery, radiotherapy, SACT); 11.4% received palliative radiotherapy alone; 6.5% underwent surgery; 33.4% received systemic anticancer therapy (SACT) as initial treatment. Platinum plus pemetrexed was the main SACT regimen used in both first and second line. Median OS (8.3 months) varied by histopathology and ranged from 4.3 to 13.3 months for sarcomatoid and epithelioid MPM, respectively. After adjusting for age, sex, and ECOG PS, sarcomatoid, biphasic, and NOS MPM remained significantly associated with worse OS than epithelioid MPM (all p < 0.001). Median OS varied from 4.6 to 17.0 months for patients receiving BSC/palliative radiotherapy, and patients receiving surgery, respectively.

Conclusion: Outcomes for patients with MPM in England remain poor. Future studies will investigate the impact of newer therapies on the treatment patterns and survival of MPM patients.