Exercise adherence and contamination in a randomized control trial of a home-based walking program among patients receiving active cancer treatment

State of the problem. Adherence has significantly affected the efficacy of a RCT to test exercise interventions. While a few studies have reported exercise pattern and adherence issues among cancer patients receiving active cancer treatment, little is known about the correlates of exercise adherence and exercise contamination in a RCT among patients receiving active cancer treatment.Methods. This study is a secondary analysis of data. The parent study is a randomized controlled clinical trial of a home-based walking intervention among patients receiving active cancer treatment. Exercise was measured by daily exercise logs.Results. 126 patients finished the study: 68 in the intervention group and 58 in the control group. The typical participants were Caucasian, 60 years old (28--80), partnered, and well-educated. Over half of the participants had prostate cancer and were receiving radiation therapy. Participants decreased their exercise levels over the study period this was especially true for exercise non-adherents. In the intervention group, participants exercised about 113 minutes and 4 sessions weekly 67.65% of these participants adhered to exercise assignment. In the control group, participants exercised about 48 minutes and 1 session weekly 12.07% of these participants did not adhere to group assignment. Independent predictors of exercise adherence are physical fitness, pre-treatment fatigue level, treatment-related mood disturbance, and marital status (p < 0.01) Past exercise history significantly predicted exercise contamination (p < 0.00).Conclusions. Study findings not only provide important information for future researchers conducting RCTs involving exercise for cancer patients receiving active treatment, but may also guide oncology clinicians in their patient care. Specifically, future researchers may be able to stratify samples based on the pre-treatment variables which are found to be significantly associated with the outcome variables in this study and therefore reduce the confounding effects of the variables. Oncology clinicians may use study findings to appropriately tailor intervention strategies which encourage exercise adherence among patients receiving active cancer treatment so that these patients can receive the known benefits of exercise.