(204) Treatment Outcomes for Advanced and Recurrent Endometrial Cancer Following Platinum-Based Chemotherapy in Canada

Publication Number: 878

Background: Endometrial cancer (EC) is the most common gynecologic malignancy in Canada.[1] Advanced and recurrent (A/R) EC has poor prognosis, particularly following progression on/after platinum-based chemotherapy (PBCT), where no standard of care exists. Novel therapies are emerging, with potential to change the treatment landscape.

Objectives: To provide real-world evidence on current treatment patterns and clinical outcomes for A/R EC patients (pts) who progressed on/after PBCT in Alberta, Canada.

Methods: This retrospective observational cohort study used health administrative data to identify pts with primary advanced EC (American Joint Committee on Cancer de novo stage ≥IIIB) or recurrent EC (progression from de novo stage I, II, and IIIA) between 2010 and 2018, with follow-up to December 2019. Treatment patterns included chemotherapy and/or hormone therapy agents. Kaplan-Meier methods were used to examine time to next treatment (TTNT; treatment initiation to initiation of subsequent treatment or any-cause death) and overall survival (OS; treatment initiation until any-cause death) from initiation of second-line (2L) chemotherapy following prior PBCT. Outcomes were stratified by disease status (A/R) and treatment type.

Results: 1053 A/R EC pts were identified; 75.2% (N=466/620) of advanced and 57.0% (N=247/433) of recurrent EC pts received first-line (1L) systemic therapy. In 1L, 96.1% of advanced and 45.3% of recurrent pts received PBCT. The study cohort included 187 advanced (N=144) and recurrent (N=43) EC pts who received 1L PBCT and initiated a 2L chemotherapy. Median TTNT for 2L chemotherapy was 6.4 months (95% CI: 5.3 to 7.7 months), and differed significantly by therapy, from 3.9 months (95% CI: 3.2 to 7.4 months) for liposomal doxorubicin (LD) to 9.9 months (95% CI: 7.1 to NA months) for carboplatin and LD. Median OS from initiation of 2L chemotherapy was 10.4 months (95% CI: 8.9 to 13.3 months) and significantly higher for those re-challenged with PBCT compared to no re-challenge (13.3 months [95% CI: 11.2 to 20.9 months] vs 6.4 months [95% CI: 4.6 to 10.4 months]; P< 0.001). Median OS also differed significantly by chemotherapy (P=0.02), from 6.7 months (95% CI: 4.5 to 11.4 months) for LD to 13.3 months (95% CI: 9.1 to 41.2 months) for carboplatin and paclitaxel. TTNT and OS did not differ statistically by disease status (P=0.5 and P=0.06, respectively).

Conclusions: Outcomes for A/R EC patients who progressed on/after PBCT in Canada represent a pressing unmet medical need that could benefit from novel therapies.

Funding: GSK (216962).

Reference: [1] Sobel M, et al. CMAJ 2021; 193:E1423.