The use of complementary medicines (CAM) in the cancer population is higher than in the general population, some studies estimate as high as 70%. With the emergence of immunotherapy as a cancer treatment option, it is important concomitant medications/CAM are assessed for immune activity that may alter the immune response. As many patients treated with immunotherapy have limited therapeutic options, it is vital that maximal activity of treatment is maintained, however, this must be balanced with the risk of the well described immune-related adverse effects of these agents.
An audit and review of CAM enquiries for patients receiving immunotherapy treatment was undertaken at our centre for the period July 2016–June 2017. CAM were reviewed utilising two evidence-based complementary medicine databases, Natural Medicines and Memorial Sloan Kettering About Herbs, to identify any potential immune activity including immunosuppressive, immunostimulatory and immunomodulatory effects. Recommendations for ceasing CAM were made where immune activity was identified or could not be determined.
Twenty-eight CAM enquiries were received (17 female, 11 male, average age 58 years, 36% skin, 18% lung, 46% other), involving 117 products and 114 different CAM, with an average of 1.5 CAM per product. Of the CAM products, 71 (60%) were identified as having immune activity, 31 (27%) had no identified immune activity and no information could be sourced for 15 (13%) products. Recommendation was made for ceasing 86 (73%) of products which may modify the immune response and could potentially affect treatment efficacy or toxicity risk.
Many CAM have postulated or proven immune activity, to help ensure safe and effective use of immunotherapy in cancer patients with limited treatment options, the use of these CAM should be considered carefully.