Tea consumption and epithelial ovarian cancer risk: a systematic review of observational studies

Ovarian cancer is the seventh most common type of cancer in the United States and is often not diagnosed until late stages. Thus, identifying potential risk factors and prevention strategies is particularly important. This systematic review analyzes existing evidence on the association between tea consumption and epithelial ovarian cancer risk in human observational studies. PubMed was searched through September 30, 2010 for eligible articles; 16 articles met the inclusion criteria for this systematic review. Five studies found overall tea intake to be associated with a decreased epithelial ovarian cancer risk, 1 found a borderline decreased risk, 9 found no association, and 1 found a borderline increased risk. Overall, it does not appear that tea consumption increases risk of ovarian cancer, but there is insufficient evidence at this point to conclude that it is protective against ovarian cancer. Many of the studies included in this review had important limitations, especially related to the lack of detailed data collected on tea consumption. Further research is needed and should focus on more detailed assessment of type of tea consumed, frequency, and duration of tea intake. Future studies should also explore potential differences in the association between tea intake and ovarian cancer risk among subpopulations.