Association of platinum-based chemotherapy with survival in ovarian carcinosarcoma: a retrospective 2-center cohort study

Ovarian carcinosarcomas, also known as malignant mixed mullerian tumors, are rare, aggressive malignancies with no set standardized chemotherapy regimen. Our retrospective study aims to compare survival outcomes in patients with ovarian carcinosarcomas treated with platinum-based chemotherapy regimens versus non-platinum-based regimens across 2 major academic centers.

A retrospective chart review was performed on patients diagnosed with ovarian carcinosarcomas between 1995 and 2023 at Yale New Haven Hospital and between 2007 and 2022 at Stanford Hospital. Inclusion criteria were comprised of patients who underwent cytoreductive surgery followed by chemotherapy. The primary outcome was overall survival. Statistical Kaplan-Meier survival curves, log-rank tests, and Cox proportional hazard regression model analyses were conducted using Prism.

Overall, 49 patients were included and there were no significant differences in baseline characteristics between the treatment groups. The median age at diagnosis was 65 years (range; 52-87) in the platinum-based group and 72.5 years (range; 57-89) in the non-platinum group. Most patients in both cohorts presented with advanced-stage disease: 28 of 37 (75.7%) in the platinum-based group and 10 of 12 (83.3%) in the non-platinum group had stage III to IV disease. In total, 37 patients (75.5%) received adjuvant platinum-based chemotherapy (predominantly carboplatin/paclitaxel), and 12 patients (24.4%) received adjuvant non-platinum-based regimens. Median overall survival was higher in the platinum-based group (59.8 months) compared to the non-platinum-based group (35.2 months, p < .05). The adjusted hazard ratio for mortality was 0.25 (95% confidence interval 0.08 to 0.77) in the platinum-based chemotherapy.

Our results suggest an observed association between platinum-based chemotherapy and improved outcomes in patients with ovarian carcinosarcoma following optimal cytoreductive surgery. Given that this is a small retrospective analysis, there is a severe selection bias and no formal non-inferiority design. As such, these findings should be considered exploratory and hypothesis-generating. The observed survival difference supports the rationale for further evaluation of platinum-based chemotherapy in ovarian carcinosarcoma in a larger, multi-institutional study designed to clarify its potential as a first-line approach.