As an oncologist, I was often asked by patients: “Doctor, what supplement shall I take to help me beat this cancer?” More often than not, this opens up a can of worms that cannot be easily addressed. I commonly give some general guidelines to my patients. For specific supplements, guidance has to take into account patients’ condition, cancer treatment regimen they are on, and a lot of other details. Many times, when there is no high level of evidence, caution has to be taken for the sake of patient safety.
Recently, an article published by Ambrosone, et al on March 10, 2020 issue of Journal of Clinical Oncology. The study titled “ Dietary Supplement Use During Chemotherapy and Survival Outcomes of Patients With Breast Cancer Enrolled in a Cooperative Group Clinical Trial (SWOG S0221)”. This is an interesting article as the authors analyzed data from SWOG S0221, a large randomized trial in studying the effectiveness of different chemotherapy schedules on early stage breast cancer. Patients enrolled in this trial were queried on their use of supplement at enrollment and during treatment. The study found that the use of antioxidant supplement (vitamins A, C, E, carotenoids, CoQ10) was associated with a trend of increased risk of cancer recurrence and death (p-value did not reach statistical significance). On the other hand, among nonantioxidant supplements, the use of B12 and iron were associated with poor survival and high recurrence, respectively.
Vitamins are often viewed as beneficial, or at least harmless in most lay press. This study deserves attention and brings further awareness that many of the seemingly harmless supplements can be detrimental, particularly when given together with chemotherapy.
As cancer treatment advances, so are the challenges to stay updated in knowledge on complementary therapy and supplements. Many studies indicate the majority of cancer patients take over the counter regimens and often without informing physicians treating their cancer. This study helps raise further awareness to this issue and potential negative effects.