The Study: Remember, PORTEC 3 suggested the addition of concurrent cisplatin and adjuvant paclitaxel / carboplatin to post-op radiation for “high-risk” endometrial cancer was not terribly helpful in women < 70 years with Stage I-II disease. This Japanese phase 3 trial now throws radiation to the wind to randomize 788 women with “high-risk” Stage I-II or any Stage III-IV endometrial cancer to one of three arms of post-op systemic therapy alone:  doxorubicin / cisplatin,  docetaxel / cisplatin, or  the PORTEC 3 paclitaxel / carbo. In both studies, "high-risk" was defined as deep myometrial invasion with high-grade or serous / clear cell histology. The primary endpoint of progression-free survival at 5 years was  73%,  79%, and  74%, and overall survival was  83%,  88%, and  86%. While not statistically significant (cough, cough), a benefit in arm  was indicated across almost all planned subset analyses. Of note, tolerability and rates of completion of all therapy were similar across arms. Side effect profiles differed as expected with more cytopenias with doxorubicin, more GI issues with cisplatin, and more neuropathy with carbo.
Bottom Line: If you’re going to use post-op chemo for high-risk endometrial cancer—which remains a big IF—docetaxel / cisplatin may be the most effective regimen. | Nomura, JAMA Oncol 2019