Palliative systemic chemotherapy in peritoneal mesothelioma: a retrospective efficacy analysis of the RENAPE database

Background The purpose of this study was to describe real-world survival outcomes associated with palliative chemotherapy in patients with peritoneal mesothelioma and to explore prognostic factors associated with progression-related and overall survival (OS). Patients and methods We retrospectively analyzed 178 patients with peritoneal mesothelioma who received palliative chemotherapy without surgery. Variables included patient characteristics, chemotherapy regimens (platinum-based versus nonplatinum-based therapy), and survival outcomes. As radiological progression dates were not consistently available, progression was approximated by time to treatment discontinuation (TTD), defined as the interval from the initiation of a palliative chemotherapy line to the start of a subsequent line, unplanned discontinuation, or death, whichever occurred first. OS was defined as the time from the initiation of palliative chemotherapy to death. Analyses were unadjusted. Results Among the 178 included patients, 139 received a first platinum-based palliative chemotherapy regimen and 67 a first nonplatinum-based regimen. Median TTD was 3.95 months [95% confidence interval (CI) 3.49-4.70 months] with platinum-based chemotherapy and 2.96 months (95% CI 2.11-6.02 months) with nonplatinum-based chemotherapy median OS was 38.9 months (95% CI 30.2-48.1 months) and 14.9 months (95% CI 7.9-25.4 months), respectively. Treatment-group comparisons were exploratory and potentially affected by indication bias. Age, histological subtype, and complete cytoreduction were associated with OS, whereas no factor was significantly associated with TTD. Outcomes did not significantly improve over time. Conclusions Palliative chemotherapy was associated with a limited TTD in peritoneal mesothelioma. In this large real-world cohort, these findings may provide a benchmark for future clinical trial design in this rare malignancy. Further research into novel treatment strategies is warranted to address the unmet needs of this population.