The University of Maryland Medical Center’s Complementary Medicine website provides an assessment of some recent studies on melatonin as an adjunct treatment for breast cancer. Of course melatonin is best known and has been most researched for its effects on sleep and its potential to address sleep disorders. Most of these investigations have focused on people whose circadian rhythms are disrupted by factors such as jet lag or work schedules, but there have also been studies looking at melatonin as a sleep aid for the elderly or for those with HIV (see other “Melatonin” entries on this Blog).
This excerpt from the UMMC article on Melatonin indicates, however, that this supplement may be eliciting additional interest as an auxiliary to certain cancer treatment regimens. We have highlighted the last sentence in this passage, which repeats one of the crucial guides in using supplements: be sure to consult your health care professional.
“Several studies indicate that melatonin levels may be linked with breast cancer risk. For example, women with breast cancer tend to have lower levels of melatonin than those without the disease. In addition, laboratory experiments have found that low levels of melatonin stimulate the growth of certain types of breast cancer cells, while adding melatonin to these cells inhibits their growth. Preliminary laboratory and clinical evidence also suggests that melatonin may enhance the effects of some chemotherapy drugs used to treat breast cancer. In a study that included a small number of women with breast cancer, melatonin (administered 7 days before beginning chemotherapy) prevented the lowering of platelets in the blood. This is a common complication of chemotherapy, known as thrombocytopenia that can lead to bleeding.
In another study of a small group of women whose breast cancer was not improving with tamoxifen (a commonly used chemotherapy medication), adding melatonin caused tumors to modestly shrink in over 28% of the women. People with breast cancer who are considering taking melatonin supplements should consult their doctors before beginning supplementation.“