麻豆传媒

Complementary and alternative medicines (CAMs), used by a number of sarcoma patients both before and during cancer treatments, are frequently associated with drug-drug interactions, according to two new studies.

Both will be presented at the upcoming European Society for Medical Oncology (ESMO) congress, held October 19-23 in Munich.

A survey of 325 patients with biopsy-proven sarcoma (59%), gastrointestinal stromal tumors (23%), and desmoid tumors (18%) found that 51% of participants had used CAMs in their lifetime -- 15% of them strictly during treatment for their disease. Interest in CAM was long-standing for 35% and inspired by their cancer diagnosis for 44%, reported Peter Hohenberger, MD, PhD, of the University of Heidelberg in Germany.

In the survey, 60% of patients recognized having inadequate safety information on CAMs, but showed low concern for any potential risks.

"When we looked at the sources of information on non-conventional practices, oncologists represented only 7%. In our study, patients mentioned repetitively that they were positively surprised about our interest in their use of CAMs," Hohenberger said in a .

Patients' reasons for using CAM included:

• Boost the immune system (78%)
• Help them feel better (76%)
• Cope with cancer treatment (45%)
• Reduce stress (53%)
• Manage symptoms or side effects (36%)

The structured survey was administered by a team from the University Hospital Mannheim in Germany over a 4-month period in 2018. The survey assessed use of treatments including supplementation of vitamins or minerals, Chinese or healing herbs, homeopathy, acupuncture, meditation, yoga, tai chi, or changes in dietary habits.

More women were CAM users than men, roughly one-third used vitamin (mostly vitamin D) and mineral supplementation. Current CAM use was equally divided between herbal medicine and homeopathic approaches at 32% each.

Respondents considered CAM an effective complement to conventional medicine, but many admitted having inadequate knowledge of the risks and benefits of CAM, and at the same time, expressed dissatisfaction with the reimbursement of CAM costs by health insurances.

The second study was a retrospective review conducted from 2014 to 2018 and included 122 soft-tissue and 80 bone sarcoma patients (103 men in all, average age of 50). Patients were treated with chemotherapy (86%) or a tyrosine kinase inhibitor (TKI, 14%).

On average, patients were taking 3 medications, 32% had at least 5 drugs; 17% used CAM, Audrey Bellesoeur, MD, of University Paris Descartes, France, reported.

"In our review, 29% of drug-drug interactions requiring pharmacist interventions were associated with complementary alternative medicines," Bellesoeur said in a .

Risks of interactions with non-conventional drugs are the same as for other co-medications: mainly increased toxicity and loss of efficacy of anti-cancer treatments, but less is known about risks of CAM therapies.

Of 157 medication reviews among 59 patients (24%), 71 required pharmacist intervention -- 34 drugs were discontinued, 16 were replaced, 2 required dose adjustments, and 19 required drug monitoring.

Notably, interventions were more frequent for patients receiving TKI compared with chemotherapy (63% versus 17%, P<0.001) and 29% of these interventions cited CAMs as being the source of the issue.

The 37 potentially severe drug-drug interactions noted were associated in univariate analysis with the following risk factors:

• Number of drugs (P<0.001)
• Performance status (P=0.04)
• Pain (P=0.002)
• Antidepressant use (P<0.001)
• Use of proton pump inhibitors (PPIs, P<0.001)
• TKI use (P<0.001)

The interactions associated with TKI, PPI, and antidepressant use remained significant in multivariate analysis (P<0.02).

"These abstracts highlight three critical issues for cancer patients using or interested in using complementary therapies during cancer treatment," Skyler B. Johnson, MD, of Yale Cancer Center in New Haven, Connecticut, told 麻豆传媒.

He noted that patients getting information from sources other than their oncologists is "problematic," as the opportunity for receiving misinformation greatly increases when non-evidence-based resources are used.

"Many [CAM] therapies are either , disproven, or proven to directly or indirectly interfere with cancer treatments, especially those with bioactive compounds or extreme diets," said Johnson, who was not involved in either study, noting that this is "information not readily available when patients rely on the internet, friends and family, or unscrupulous alternative practitioners."

He noted that the study from Bellesoeur's group not only highlights the potential drug-drug interaction risks of CAMs, but also points to a potential solution.

"The use of a pharmacist to perform medical reconciliations as well as modifications to avoid potential complications during treatment is a novel and patient-centered approach to improving cancer treatment outcomes that should be investigated further," he said.

Johnson suggested that patients should use all physician-recommended therapies, and if they are inclined to pursue complementary therapies, an emphasis on mind therapies that will improve quality of life should strongly be encouraged -- massage, meditation, yoga, tai chi, etc. He said that use of systemic CAMs should be avoided.

This reflects evidence collected so far in the , which ESMO has noted support the benefits of physical exercise, mindfulness-based stress reduction programs, hypnosis, yoga, and acupuncture in supportive care but not other systemic therapies.

In a statement for ESMO, Markus Joerger, MD, PhD, of Cantonal Hospital in St. Gallen, Switzerland, said: "Cancer centers must also invest in integrative medicine that combines medical anti-cancer treatments with non-conventional therapies. The average oncologist has poor knowledge of these alternative methods; this is mostly due to a lack of studies and databases in the field. More efforts are needed to understand how to deliver mixed treatments safely and to build up experience to better advise our patients."

Further, to promote consensus on the meaning of integrative oncology, ESMO encourages use of the more precise definition of complementary and integrative medicine (CIM) when referring to all complementary treatments being used side-by-side with conventional therapies in controlled settings rather than the acronym CAMs, which traditionally also includes treatments used instead of scientifically based medicine, he added.

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