Pre- and post-polyphenol intake and ovarian cancer survival: evidence from a prospective cohort study.

Purpose: Although (poly)phenols have shown potential in anti-cancer activities, their impact on improving ovarian cancer (OC) survival remains unknown. Therefore, we aim to first investigate the association between dietary polyphenol intake and OC survival, providing valuable insights into potential interventions.

Methods: The prospective cohort recruited 560 patients with OC to assess the associations of polyphenol intake, not only pre- and post-diagnosis but also the change from pre- to post-diagnosis with OC survival. Dietary intakes of total (poly)phenols and their five classes (flavonoids, phenolic acids, lignans, stilbenes, and other polyphenols) were assessed using a validated 111-item food frequency questionnaire. Overall survival (OS) was tracked through active follow-up and medical records until February 16th, 2023. Cox proportional hazard regression models were applied to calculate the hazard ratios (HR) and 95% confidence intervals (CI).

Results: During a median follow-up of 44.4 months, 211 all-cause deaths were identified. We observed significant associations between higher polyphenol intake with lower risk of mortality among patients with OC ((HR _{T3 vs. T1} = 0.55, 95%CI = 0.35-0.87 for pre-diagnosis; and HR _{T3 vs. T1} = 0.59, 95%CI = 0.39-0.90 for post-diagnosis). Consistently, an evident linear trend was observed for polyphenol and flavonoid intake with OC survival. Of note, compared to the stable group (change within 10%), the decreased intake (change of more than 10%) of total (poly)phenols and five polyphenol classes was significantly associated with worse OS.

Conclusion: Dietary (poly)phenols, as well as its five classes, have an inverse association with OC survival.