Complementary and Alternative Medicine (CAM) Use in Patients Undergoing Radiotherapy: Sex-specific Prevalence and Associations of Use Based on the S3 Guideline Complementary Medicine in Oncology Questionnaire.

Background/aim: This study aimed to assess the sex-specific prevalence and patterns of complementary and alternative medicine (CAM) use in patients undergoing radiotherapy, using the standardized questionnaire developed as part of the S3 Guideline on Complementary Medicine in Oncology.

Patients and methods: Between August and December 2022, 112 out of 697 eligible cancer patients receiving radiotherapy were prospectively enrolled and completed a structured questionnaire assessing CAM use. The questionnaire included 38 CAM methods classified according to their potential for interactions.

Results: Female participants generally used more CAM methods than male participants (median methods: 3 vs. 1, p<0.001). The most frequently used CAM methods were vitamin D (46.4%), sports/exercise (33%) and vitamin A/C/E or beta-carotene (25%). At least one of the listed CAM methods was used by 79.5%. At least three of the listed CAM methods were used by 52 (46.4%) patients. Thirty-six (32.1%) and 54 (48.2%) patients used CAM methods with known or potential interactions, while 76 (67.9%) used methods with no known interactions. In addition, a higher number of female patients used uncertain methods or medications compared to males (p=0.022). The desire for counseling was very similar between both sexes, with no significant difference (p=0.973).

Conclusion: The high rate of CAM utility before radiotherapy, especially among females, and the use of uncertain methods, highlights the need for standardized questionnaires to identify potential interactions. This would help enhance patient safety through structured screening and counseling.