A national study has found that one-third of patients with cancer and cancer survivors reported using complementary and alternative medicine (CAM) in the past year, but 29% of these individuals did not disclose use of CAM to their physician.

Complementary and alternative medicine (CAM) —therapies that are used in addition to or instead of conventional treatments—are frequently used by patients with cancer and cancer survivors in the United States, but there are growing concerns about its use. “A 2018 study found that patients using CAM were more likely to refuse additional conventional cancer treatments and die as a result, but the proportion of participants using CAM in that investigation was very low,” explains Nina N. Sanford, MD. “Data are needed to determine whether patients with cancer and survivors of the disease are disclosing use of CAM to their physicians and the reasons why they may not disclose this information.”

To address this issue, Dr. Sanford and colleagues had a research letter published in JAMA Oncology that used data from the National Health Interview Survey (NHIS) to estimate the proportion of patients with cancer and cancer survivors who used CAM and analyze rates of CAM nondisclosure. In 2012, the NHIS included a supplement on CAM use. Data on CAM use and on patient demographics among those reporting a diagnosis of cancer were obtained through the Integrated Health Interview Series.

Highlighting Key Results

Among the more than 3,000 participants who reported a history of cancer, about one-third indicated that they used CAM in the past 12 months. The most commonly used CAM modality was herbal supplements (about 36%), followed by chiropractic or osteopathic manipulation (25%) and massage. Caucasian race, female sex, non-Hispanic ethnicity, and younger age were factors associated with a higher likelihood of CAM use. “Importantly, nearly 30% of patients with cancer and cancer survivors who engaged in CAM did not disclose this information to their healthcare providers,” says Dr. Sanford. When the study cohort was restricted to patients with cancer who were diagnosed up to 2 years prior to taking the survey, about 33% reported using CAM and nearly 29% did not disclose CAM use to their physician (Table).

The study also examined reasons for not disclosing use of CAM. More than half of respondents reported that it was because their physician did not ask about using such treatments. Another 47% reported that they did not think their physicians needed to know they used CAM. Few CAM users reported feeling that their physician did not know much about CAM. “Most patients did not express concerns about a negative reaction from their physician for using CAM,” Dr. Sanford adds. Patients also did not commonly report being worried that their physician would discourage CAM use or that was discouraged in the past.

Assessing Implications

People with cancer and cancer survivors may have many motivations for seeking CAM. Some may wish to use it to manage persistent symptoms or psychological distress, while others seek to gain a sense of control over their care. According to Dr. Sanford, it is important for physicians to be proactive and ask patients about their CAM use. “A large proportion of patients will not openly disclose using CAM,” she says. “Patients need to be asked directly if they are using CAM and the types they use, because some CAM may be harmful. They also need to be given time and space to further discuss these treatments.” Given the high proportion of patients with cancer and cancer survivors reporting use of CAM, further study is warranted. “In particular, robust studies are needed to understand the efficacy and toxicities of CAM therapies, particularly in combination with conventional cancer treatments,” says Dr. Sanford. “Analyses assessing costs and quality of life in patients who use CAM are also needed. Furthermore, research is necessary to better understand if using CAM is truly associated with refusal of conventional therapy and worse survival. The implications of CAM will likely depend on the specific modality used.”