Phytosterol intake and overall survival in newly diagnosed ovarian cancer patients: An ambispective cohort study

BACKGROUND: Phytosterol is a bioactive compound existing in all plant foods, which might have anticancer properties. The aim of this study was to first assess the impact of the pre-diagnosis phytosterol intake on overall survival (OS) of patients with ovarian cancer (OC). MATERIALS AND METHODS: This ambispective cohort study recruited 703 newly diagnosed OC patients to investigate the aforementioned associations. Dietary intake was assessed using a validated 111-item food frequency questionnaire. Deaths were ascertained until March 31, 2021, through active follow-up and medical records. Cox proportional hazards regression models were applied to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: During the median follow-up of 37.17 months, 130 deaths occurred. The median age at diagnosis of 703 OC patients was 53.00 (interquartile: 48.00–60.00) years. Of these, almost half patients (48.08%) were diagnosed in advanced International Federation of Gynecology and Obstetrics (FIGO) stage (III-IV). Additionally, more than half patients were serous carcinoma (68.14%), poorly differentiated (85.21%), and no residual lesions (78.66%). Patients consumed the highest tertile of dietary campesterol (HR = 0.54, 95% CI = 0.31–0.94, P trend < 0.05), stigmasterol (HR = 0.60, 95% CI = 0.37–0.98), and β-sitosterol (HR = 0.63, 95% CI = 0.40–0.99) were significantly associated with better OS compared with those with the lowest tertile of intake. The curvilinear associations were observed between total phytosterols and β-sitosterol intake and OC survival (P non-linear < 0.05). Significant associations were generally consistent across different subgroups stratified by demographical, clinical, and immunohistochemical characteristics. Moreover, there were significant interactions between phytosterol intake and age at diagnosis, body mass index, as well as expressions of Wilms’ tumor-1 and Progestogen Receptor (all P interaction < 0.05). CONCLUSION: Pre-diagnosis higher campesterol, stigmasterol, and β-sitosterol intake were associated with better survival among OC patients.