Physical activity and exercise during curative oncological treatment : exploring the effects of exercise intensity and behaviour change support, safety, and patients’ and exercise professionals’ experiences

Aims: This thesis aimed to explore the effects of exercise intensity and behaviour change support (BCS), the safety of exercise, and experiences of exercise for both patients and exercise professionals during oncological treatment (e.g. neo/adjuvant chemotherapy, endocrine treatment, radiotherapy). This thesis is based on data from the Phys-Can (Physical training and Cancer) multicentre research program, consisting of a feasibility study, an observation study, and a randomised controlled trial (RCT). Methods: Paper I and II were quantitative studies. Paper I was a RCT with a 2x2 factorial design. Patients newly diagnosed with breast, prostate, or colorectal cancer about to start oncological treatment were randomised to six months of high intensity (HI) or low-moderate intensity (LMI) supervised group based resistance- and home-based endurance training, with or without additional BCS. The primary outcome, cancer related fatigue (CRF), was assessed by the Multidimensional Fatigue Inventory. Multiple linear regression and additional responder analysis for primary outcomes were performed. Paper II was a descriptive and comparative study based on secondary data from the observation study and RCT. Data were presented descriptively, and related factors to adverse events (AEs) were analysed with logistic regressions. Paper III and IV were qualitative studies. Participants were patients with breast, prostate, or colorectal cancer undergoing oncological treatment (Paper III) or coaches supervising exercise for participants in the RCT (Paper IV). Data were collected through semi-structured individual- (Paper III and IV) and focus group interviews (Paper III) and analysed with qualitative content analysis (Paper III) and thematic analysis (Paper IV). Main results and conclusions: The results from this thesis indicate that exercise at HI may not improve CRF in comparison with exercise at LMI in patients undergoing treatment, thus patients can be advised to exercise at either preferred intensity. Also, additional BCS did not improve CRF in relatively motivated patients receiving supervised exercise (Paper I). Furthermore, exercise-related AEs in persons undergoing oncological treatment are minor, of musculoskeletal origin, and with a similar incidence as in healthy populations. However, a higher risk of minor exercise-related AEs was reported in HI groups than in LMI groups. More serious AEs were rare, thus it seems safe to exercise even at HI for these patient groups (Paper II). The results also indicated that patients could experience side effects and concerns regarding the safety of exercising during oncological treatment as barriers to engage in physical activity. Therefore, engaging in physical activity before the onset of side effects from treatment and providing information regarding physical activity to patients could be beneficial (Paper III). Professionals supervising exercise for patients may find it highly rewarding, which is promising for implementation in cancer rehabilitation. However, patients may still receive contradictory information regarding the safety of exercise from health care staff, which can be difficult for exercise professionals to counteract (Paper IV)