Predictive factors for the use of complementary and alternative medicine (CAM) in radiation oncology

Background

In recent years, the demand and use of complementary and alternative medicine (CAM) in malignant diseases has increased noticeably. Since the general knowledge about CAM use is scant, patients often do not communicate their CAM use to the responsible oncologist, and CAM could potentially interact with standard therapies in the German Working group “Trace Elements and Electrolytes in Oncology” performed a multi-center study to identify factors to predict the CAM use in radiotherapy patients giving the patients the information and the support they demand.

Methods

A total of 1013 consecutive patients (53% male) receiving radiotherapy for malignant diseases were interviewed using a standardized structured questionnaire including clinical and pathological tumor parameters as well as the type of CAM, reasons for use and source of CAM therapies. A self-assessment of patients’ personal conditions was performed to evaluate the subjective impact of CAM on quality of life.

Results

A total of 59% patients reported using CAM therapies. CAM use was more common in female patients (66% female, p=0.007), generally higher in advanced stages of disease (<0.05 of all comparisons) and most common in breast cancer patients (91%) followed by patients with Hodgkin's disease (83%), other gynecologic malignancies (60%), renal cell carcinoma (50%), rectal cancer (50%), and prostate cancer (47%). The frequency of CAM use was lowest in head and neck cancer patients (36%). Most frequently reported CAM therapies were vitamins (18%), mistletoe extracts (15%), selenium (10%), and other trace element preparations (7%). Multi-variate logistic stepwise backward regression showed age, gender, tumor type and stage, and smoking behavior to be significant predictors for CAM use. The highest relative risk was calculated for breast cancer patients, followed by patients with Hodgkin's disease. The lowest relative risk was calculated for head and neck cancer patients.

The most often reported source of information and prescription was the general practitioner. A subjective improvement in quality of life that patients considered due to the use of CAM was accounted in 30% of patients.

Conclusions

The current study represents the largest analysis of CAM use in cancer patients. Simplified, the typical CAM user is female, suffering from breast cancer, non-smoker, non-drinker, has an advanced stage of disease and is treated with curative intention. These findings also reflect clinical experience that younger patients with progressive disease and poor prognosis apply “every method available”.

More than half of the patients undergoing RT for cancer are using CAM therapies. In order to identify these patients, to avoid harmful interactions with conventional therapy, and bias in clinical trials, radiation oncologists should include this topic in the standard patient history evaluation. The value or potential hazards of such treatment have yet to be tested in further clinical studies.

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