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 non-users of CAM, according to a new study.
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.
Dr Heather Greenlee, of the Mailman School of Public Health at Columbia University, New York, and co-authors studied a group of 685 women with early-stage breast cancer who were recruited from multiple sites. The women were younger than 70 with non-metastatic 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 summarizing 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% (135 women).
Most of the study participants, 598 women or 87%, 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%) 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 non-initiation reflects long-standing decision-making patterns among study participants.
“Though the majority of women with clinically indicated chemotherapy initiated treatment, 34 of 306 (11%) 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.
“Taken together, the available studies, including the important addition to the literature by Greenlee and colleagues … showing that CAM use may be associated with non-initiation of potentially life-saving adjuvant treatment, highlight the urgent need to train oncologists to enhance their ability to improve patient disclosure of CAM. This can best be done in a patient-centred manner by respectfully exploring patients’ preferences and beliefs about CAM and by providing the best evidence-based information about treatment options in a non-judgmental fashion,” writes Dr Robert Zachariae, of Aarhus University Hospital, Aarhus, Denmark in a linked comment.
Importance: Not all women initiate clinically indicated breast cancer adjuvant treatment. It is important for clinicians to identify women at risk for noninitiation.
Objective: To determine whether complementary and alternative medicine (CAM) use is associated with decreased breast cancer chemotherapy initiation.
Design, Setting, and Participants: In this multisite prospective cohort study (the Breast Cancer Quality of Care [BQUAL] study) designed to examine predictors of breast cancer treatment initiation and adherence, 685 women younger than 70 years with nonmetastatic invasive breast cancer were recruited from Columbia University Medical Center, Kaiser Permanente Northern California, and Henry Ford Health System and enrolled between May 2006 and July 31, 2010. Overall, 306 patients (45%) were clinically indicated to receive chemotherapy per National Comprehensive Cancer Network guidelines. Participants were followed for up to 12 months.
Exposures: Baseline interviews assessed current use of 5 CAM modalities (vitamins and/or minerals, herbs and/or botanicals, other natural products, mind-body self-practice, mind-body practitioner-based practice). CAM use definitions included any use, dietary supplement use, mind-body use, and a CAM index summing the 5 modalities.
Main Outcomes and Measures: Chemotherapy initiation was assessed via self-report up to 12 months after baseline. Multivariable logistic regression models examined a priori hypotheses testing whether CAM use was associated with chemotherapy initiation, adjusting for demographic and clinical covariates, and delineating groups by age and chemotherapy indication.
Results: A cohort of 685 women younger than 70 years (mean age, 59 years; median age, 59 years) with nonmetastatic invasive breast cancer were recruited and followed for up to 12 months to examine predictors of breast cancer treatment initiation. Baseline CAM use was reported by 598 women (87%). Chemotherapy was initiated by 272 women (89%) for whom chemotherapy was indicated, compared with 135 women (36%) for whom chemotherapy was discretionary. Among women for whom chemotherapy was indicated, dietary supplement users and women with high CAM index scores were less likely than nonusers to initiate chemotherapy (odds ratio [OR], 0.16; 95% CI, 0.03-0.51; and OR per unit, 0.64; 95% CI, 0.46-0.87, respectively). Use of mind-body practices was not related to chemotherapy initiation (OR, 1.45; 95% CI, 0.57-3.59). There was no association between CAM use and chemotherapy initiation among women for whom chemotherapy was discretionary.
Conclusions and Relevance: CAM use was high among patients with early-stage breast cancer enrolled in a multisite prospective cohort study. Current dietary supplement use and higher number of CAM modalities used but not mind-body practices were associated with decreased initiation of clinically indicated chemotherapy. Oncologists should consider discussing CAM with their patients during the chemotherapy decision-making process.