Women with early-stage breast cancer for whom chemotherapy was indicated and who used dietary supplements and multiple types of complementary and alternative medicine (CAM) were less likely to start chemotherapy than nonusers of CAM, according to a new study published online by JAMA Oncology.

Not all women initiate adjuvant treatment for breast cancer despite the survival benefits associated with it.

The decision to initiate chemotherapy involves psychosocial factors, belief systems, and clinical, demographic and provider characteristics.

CAM use among patients with breast cancer has increased in the past two decades but few studies have evaluated how CAM use affects decisions regarding chemotherapy.

Heather Greenlee, N.D., Ph.D., of the Mailman School of Public Health at Columbia University, New York, and coauthors studied a group of 685 women with early-stage breast cancer who were recruited from multiple sites.

The women were younger than 70 with nonmetastatic invasive breast cancer.

The study included five types of CAM (vitamins and/or minerals, herbs and/or botanicals, other natural products, mind-body self-practice, and mind-body practitioner-based practice) and created a CAM index summarising the number of types of CAM used.

Overall, 306 women were clinically indicated to receive chemotherapy based on guidelines and the remaining women were considered to have a discretionary recommendation for chemotherapy.

By 12 months, most of the women — 272 or 89 percent — for whom chemotherapy was indicated initiated treatment.

The group of women for who chemotherapy was discretionary had a much lower rate of initiation of 36 percent (135 women).

Most of the study participants, 598 women or 87 percent, reported CAM use at baseline.

The common CAM types were the use of dietary supplements and mind-body practices.

The median number of CAM modalities used was two and 261 women (38 percent) reported using three or more types of CAM.

The use of mind-body practices was not related to chemotherapy initiation.

However, the use of dietary supplements and a higher CAM index score among women for whom chemotherapy was indicated were associated with a lower likelihood to initiate chemotherapy than nonusers, according to the results.

Authors report there was no association between starting chemotherapy and CAM use among women for whom chemotherapy was discretionary.

The authors note it is important to consider possible alternative explanations for their findings.

Also, it is unclear whether the association between CAM use and chemotherapy noninitiation reflects long-standing decision-making patterns among study participants.

"Though the majority of women with clinically indicated chemotherapy initiated treatment, 34 of 306 (11 percent) did not. A cautious interpretation of results may suggest to oncologists that it is beneficial to ascertain CAM use among their patients, especially dietary supplement use, and to consider CAM use as a potential marker of patients at risk of not initiating clinically indicated chemotherapy," the authors conclude.

Source: JAMA Network