Association between pre-diagnosis and post-diagnosis Alternate Mediterranean Diet and ovarian cancer survival: evidence from a prospective cohort study

Background: There is currently a lack of comprehensive evidence regarding the correlation between Alternate Mediterranean Diet (AMED) and the survival of patients with ovarian cancer (OC). This prospective cohort study first assessed the association of AMED, not only pre-diagnosis and post-diagnosis but also the change from pre-diagnosis to post-diagnosis with OC survival.

Methods: A total of 560 OC patients were included in the study, and their dietary intake was assessed using a reliable 111-item food frequency questionnaire. The overall survival (OS) of the patients was monitored through active follow-up and review of medical records until February 16th, 2023. Cox proportional hazard regression models were utilized to compute the hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs).

Results: Out of the total 560 patients with OC, 211 (37.68%) succumbed during a median follow-up period of 44.40 months (interquartile range: 26.97-61.37). Comparative analysis indicated a significant association between the highest tertiles of pre-diagnosis (HR = 0.59; 95% CI 0.38-0.90; P_trend < 0.05) and post-diagnosis (HR = 0.61; 95% CI 0.41-0.91; P_trend < 0.05) AMED intake and improved OS as opposed to the lowest tertile. Additionally, a significant linear trend was observed for AMED and OC survival. Notably, decreased intake (more than 5% change) and significantly increased intake (more than 15% change) of AMED from pre-diagnosis to post-diagnosis were linked to worse and better OS, respectively, when compared to the stable intake group (change within 5%). Furthermore, patients displaying consistently higher AMED intake both before and after diagnosis experienced enhanced OS in comparison to those with consistently low AMED intake (HR_{High-High vs. Low-Low} = 0.47; 95% CI 0.31-0.70).

Conclusion: High pre-diagnosis and post-diagnosis AMED was associated with an improved OS in patients with OC, suggesting that maintaining a consistently high intake of AMED could potentially benefit the prognosis of OC.