Complementary and alternative medicine use in cancer: A systematic review.

•CAM use by cancer patients can be a safety concern due to risks of interactions with anti-cancer therapy.•This systematic review has identified prevalence, predictors and reasons for CAM use by cancer patients.•Prevalence of CAM use was found to be 51% in cancer patients.•Young, female, higher educated and higher earning cancer patients were found more likely to use CAM.•The most common reason (thematic analysis) for CAM use was to treat or cure their cancer.