Date Published: May 8, 2019
Publisher: Public Library of Science
Author(s): Lenja Witlox, Miranda J. Velthuis, Jennifer H. Boer, Charlotte N. Steins Bisschop, Elsken van der Wall, Wout J. T. M. van der Meulen, Carin D. Schröder, Petra H. M. Peeters, Anne M. May, Giandomenico Roviello.
Maintaining high adherence rates (session attendance and compliance) in exercise programs during breast cancer treatment can be challenging. We aimed to identify adherence rates and predictors to an exercise program during adjuvant breast cancer treatment.
Ninety-two patients with localized breast cancer undergoing chemotherapy were randomly assigned to an 18-week supervised moderate-to-high intensity aerobic and resistance exercise program, including two 1-hour sessions/week. Additionally, participants were asked to be physically active for at least 30 minutes/day on at least three other days. We report median percentages for attendance, compliance with the prescribed duration and intensity of aerobic and muscle strength exercises, and the exercise advice given. Predictors included in univariate and multivariable linear regression models were demographical, tumor- and treatment-related factors, constructs of the theory of planned behavior, psychological and physical factors.
Patients attended 83% (interquartile range: 69–91%) of the supervised sessions. Compliance with the duration of aerobic exercise, high-intensity aerobic exercise (cycling at the ventilatory threshold), muscle strength exercises and the exercise advice were 88%(64–97%), 50%(22–82%), 84%(65–94%) and 61%(33%–79%), respectively. Education, radiotherapy, BMI and physical fatigue were important predictors of adherence to supervised exercise. Beliefs about planned behaviors were important predictors, especially for compliance with the exercise advice.
Attendance to and compliance with an 18-week aerobic and strength exercise program were high. The lowest compliance was found for high-intensity supervised aerobic exercise. The identified predictors should be considered when designing or adapting exercise programs for patients with localized breast cancer to increase adherence.
Current Controlled Trials ISRCTN43801571
In our randomized Physical Activity during Cancer Treatment (PACT) study, we showed that an 18-week exercise program had beneficial effects on fatigue and physical fitness in newly diagnosed breast cancer patients undergoing adjuvant treatment . Several meta-analyses have also reported that supervised exercise interventions during cancer treatment have positive effects on cancer-related fatigue, physical functioning and quality of life [2–6]; however, in general the reported effect sizes were small [1, 7].
This explorative study shows high adherence rates to an 18-week aerobic and muscle strength exercise program in primary breast cancer patients during treatment, both in terms of attendance rates and compliance rates, with the exception of compliance to the high intensity exercises. The attendance rate (83%) was higher than in previous trials investigating the use of exercise programs in breast cancer patients undergoing chemotherapy, whose attendance rates of twice weekly supervised sessions ranged from 71–79% [15–17]. This might be explained by the incorporation of cognitive behavioral aspects into our exercise program or differences in patient characteristics, such as baseline activity levels, which were high in the PACT population. In addition, the intensity of supervision might have differed. In the PACT study, patients either trained in small groups or alone, and the physiotherapists explicitly encouraged the patients to attend the sessions even though they were not feeling well. Note, that physiotherapists are exercise specialists and internationally other allied health trained exercise professionals can adopt and use this intervention.