By Ankur Banerjee

(Reuters Health) – One in three U.S. patients with a cancer diagnosis has recently used non-standard therapies to manage their disease – but many haven’t told their doctors, survey data suggest.

Among patients who said they used so-called complementary and alternative therapies, such as herbal supplements and yoga, nearly 30 percent did not disclose this use to their physicians, researchers wrote in a letter published in JAMA Oncology.

This finding is worrisome, they say. The letter cites an earlier National Cancer Database study that found patients who were using complementary medicine were more likely to stop using conventional cancer therapies – and when that happened, they had poorer outcomes.

The lack of sharing in the current study was not necessarily because patients worried their doctors would respond negatively, lead author Dr. Nina Sanford, of the University of Texas Southwestern in Dallas, told Reuters Health.

Most often, “patients thought their providers did not need to know, or the providers did not ask,” Sanford said by email.

Patients who didn’t share the information also said their physician did not know as much about the therapy, or they were not given enough time to tell about therapy.

People with cancer may have many motivations for seeking complementary and alternative therapies, the authors wrote, including persistent symptoms, psychological distress, or to gain a sense of control over their care.

Dr. David Spiegel of Stanford University School of Medicine in California, who was not involved in the study, concurred, writing in an email to Reuters Health that most often the patients use alternative medicines to help with pain and stress.

“It is always best if doctors ask and discuss the use of such treatments in an open way that invites cooperation, which should include discussions of possible risks and the importance of adherence to standard medical care,” Spiegel said.

For the study, Sanford and colleagues analyzed data from 3,118 adults who participated in the 2012 National Health Interview Survey and reported a history of cancer. Of this group, 1,023 reported use of complementary or alternative therapies in the past year, including 288 who said they did not tell their doctor.

The most popular alternative was herbal supplements, followed by chiropractic or osteopathic manipulation and then massage.

The study authors acknowledge that the U.S. data may not be generalizable to international populations. Furthermore, the data were collected seven years ago.

Still, Sanford said, cancer patients and survivors appear to be increasingly using complementary and alternative medicines and therapies, even though many of the approaches lack research documenting their effectiveness and side effects.

Sanford and colleagues call for development of medical guidelines that encourage doctors to discuss complementary alternative therapies with patients, and also for additional research to asses quality of life, health outcomes and cost implications tied to use of such therapies.

SOURCE: JAMA Oncology, online April 11, 2019.