Green tea consumption, primary treatment outcome and survival after a diagnosis of ovarian cancer.

Abstract

Background: Drinking green tea prior to a diagnosis of ovarian cancer has been associated with improved survival; however, research on post-diagnosis consumption is limited. We investigated whether consuming green tea during primary chemotherapy was associated with improved treatment response and whether green tea drinking pre-diagnosis or post-treatment was associated with survival.

Methods: We used data from the Ovarian Cancer Prognosis and Lifestyle study, an Australian prospective cohort of 958 women with epithelial ovarian cancer. Tea consumption was self-reported at baseline and at 3 monthly intervals following diagnosis. Logistic regression was used to estimate ORs and 95% CIs for the association between green tea consumption during primary treatment and outcome. Flexible parametric survival models were used to estimate HRs and 95% CIs for the associations between green tea pre-diagnosis and post-treatment and survival. Black and herbal tea were included as negative controls.

Results: No association was seen between green or black tea consumption during chemotherapy and treatment response. There was a suggestion that drinking at least one cup/day of green tea in the pre-diagnosis or post-treatment periods was associated with improved overall survival (pre-diagnosis: HR=0.78, 95%CI=0.60 to 1.00; post-treatment: HR=0.84, 95%CI=0.66 to 1.04), but not progression-free survival. Conversely, herbal tea consumption post-treatment was associated with improved progression-free but not overall survival.

Conclusions: We confirmed previous results suggesting green tea may be associated with better ovarian cancer survival but cannot rule out the possibility that residual confounding may be influencing these associations. Randomised trials are required to confirm any potential benefit.