Pauline Corbaux, Benoît You, Iain McNeish, Stephen Welch, Anna V. Tinker, Mansoor R. Mirza, Kristina Lindemann, Tatsuo Kagimura, Isabelle Ray‐Coquard, Fabien Subtil, Julien Péron, Karen Carty, Caroline Kelly, Olivier Colomban, Eleni Karamouza, Adrian Cook, Xavier Paoletti, Rosalind Glasspool, Nozomu Yanaihara
OBJECTIVE: Growing evidence suggests potential ethnic and geographical variations in chemotherapy efficacy. The CA125 ELIMination rate constant K score is a pragmatic and reproducible indicator of tumor chemosensitivity in newly diagnosed ovarian cancer. We compared ELIMination rate constant K distributions and prognostic performances between patients enrolled in Japanese and Western trials who had stage III/IV serous ovarian cancer from the Gynecologic Cancer InterGroup individual-patient-data Meta-Analysis in OVarian cancer. METHODS: The ELIMination rate constant K values were previously estimated for 5884 women receiving first-line chemotherapy for ovarian cancer. Data from 246 women enrolled in the Japanese JGOG-3016 trial were compared to 2561 patients from Western trials. ELIMination rate constant K was analyzed as a binary variable (favorable ≥1.0 vs unfavorable <1.0). Prognostic value for progression-free survival and overall survival was assessed using univariable and multi-variable models. A standardization cut-off specific to patients enrolled in the Japanese trial was explored using maximally selected rank statistics. RESULTS: strengthened prognostic discrimination (progression-free survival: hazard ratio 0.35, 95% confidence interval 0.25 to 0.49, p <.0001; overall survival: hazard ratio 0.40, 95% confidence interval 0.26 to 0.61, p <.0001). CONCLUSIONS: Potential higher ELIMination rate constant K-assessed chemosensitivity is suggested in patients from Japan with advanced serous ovarian cancer, warranting further prospective validation and investigation into underlying biological and environmental determinants and implications for personalized therapeutic strategies.