Abstract P1-10-09: Are patients with breast cancer undergoing adjuvant treatment able to follow an exercise program with a moderate to high intensity?
Authors: May AM , Boer JH , Velthuis M , Steins Bisschop CN , Los M , Erdkamp F , ten Bokkel Huinink D , Bloemendal HJ , Rodenhuis C , de Roos MAJ , Verhaar M , van der Wall E , Peeters PHM 
Published: May 2016

PURPOSE: We recently showed in a randomized trial, the Physical Activity during Cancer Treatment (PACT) study, that an 18-week exercise program reduced complaints of fatigue and improved physical fitness in newly diagnosed breast cancer patients undergoing adjuvant treatment. The beneficial effects were probably underestimated due to high levels of physical activity in the control group that received usual care only. Another possibility for dilution of the effect might be limited participation of the intervention group in the supervised exercise program or low compliance, i.e., an adjustment of the prescribed exercise protocol. We set out to study participation and compliance and to find determinants of reduced compliance.

METHODS: 102 patients in the PACT study were randomized into the intervention group that received a supervised exercise program 2 times a week for 18 weeks (36 sessions in total). Each session had a duration of 60 minutes and included a pre-specified period of aerobic interval exercises of specific intensities as well as muscle strength exercises. Sessions were supervised by physiotherapists, intensity was based on individual fitness characteristics and results were kept in a log.

We computed attendance (percentage of total sessions attended) and compliance (adherence to the prescribed duration and intensity of the aerobic part and to the muscle strength part of each attended session). We computed for each woman the percentage of sessions the women complied with the protocol, and report median percentages for compliance with the aerobic exercises, duration and intensity, and with the muscle strength exercises separately. Determinants of low compliance that were included in linear regression models were: age, behavioral, physical and psychosocial factors.

RESULTS: For 92 patients exercise logs were available. Patients were, on average, 50.2±7.8 years of age, all patients received chemotherapy and 70% received radiotherapy. Participation was high: patients participated in 83% (interquartile range 69-91%) of the sessions offered. Overall, also compliance was high: in 88% (63-97%) and 84% (65-94%) of all attended sessions patients were able to complete the aerobic (duration) and muscle strength program, respectively, as prescribed in the protocol. Compliance to the high-intensity part of the aerobic program was lower: in 50% (22-82%) of the sessions the intensity of the aerobic exercises was adjusted. Especially patients who received radiotherapy in addition to chemotherapy and patients who were more physically fatigued at baseline had a lower compliance to the high-intensity part of the aerobic exercises (β=-5.3 (confidence interval -9.4;-1.2) and β=-0.6 (-1.0;-0.1), respectively).

CONLUSIONS: Participation in and compliance to an 18-week aerobic and muscle strength exercise program was high. Thus, patients are well capable to exercise during adjuvant treatment for breast cancer. This study shows that preferably high intensity aerobic exercises were adjusted in a significant number of participants rather than the duration or the strength exercises. This has to be taken into account when developing training programs, especially in those patients who receive both, radiotherapy and chemotherapy.

Citation Format: May AM, Boer JH, Velthuis M, Steins Bisschop CN, Los M, Erdkamp F, ten Bokkel Huinink D, Bloemendal HJ, Rodenhuis C, de Roos MAJ, Verhaar M, van der Wall E, Peeters PHM. Are patients with breast cancer undergoing adjuvant treatment able to follow an exercise program with a moderate to high intensity?. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-10-09.