Lifestyle behaviour change and cancer-related fatigue among colorectal cancer survivors

Samenvatting

Cancer-related fatigue is a multifactorial symptom, which can be influenced by demographic, medical, psychosocial, behavioural, and biological factors. There is a lack of understanding of the underlying mechanisms and causes of cancer-related fatigue. Anemia might be one of the contributing factors to cancer-related fatigue. In Chapter 2, we showed that anemia, assessed from hematocrit levels in blood, was present in 16% of colorectal cancer (CRC) survivors two years after diagnosis. Lower blood levels of hematocrit were associated with higher prevalence and severity of cancer-related fatigue over time.

Observational data suggest an association between healthy lifestyle behaviours, particularly consuming a healthy diet and sufficient physical activity, and lower severity of cancer-related fatigue among CRC survivors. However, evidence from intervention studies with CRC survivors who experience cancer-related fatigue is scarce. Therefore, we designed a program, which aimed to improve lifestyle among CRC survivors who completed treatment and who experience cancer-related fatigue (Chapter 5). The effectiveness of this program was tested in a randomized controlled trial (RCT) (Chapter 5).

To design the lifestyle program, we conducted a literature review to identify determinants of healthy lifestyle behaviours in CRC survivors that we could target in the program (Chapter 3). We observed that, amongst others, several intrapersonal factors (e.g., motivation, self-efficacy) and disease-related symptoms were important determinants of lifestyle behaviours in CRC survivors post-treatment. In Chapter 4, we conducted a literature review to examine, amongst others, which behaviour change techniques were most promising in lifestyle interventions for effectively reducing cancer-related fatigue in cancer survivors who finished primary treatment. The technique ‘Generalisation of the target behaviour (i.e., implementing the newly learned behaviour in the own context)’ was the only technique identified as most promising for effectively reducing cancer-related fatigue through lifestyle change. This preparatory work led to the development of a lifestyle program, with a core focus on sustained behaviour change, tailored to CRC survivors who completed treatment. The lifestyle program was person-centred with regards to: 1) Lifestyle and personal characteristics, 2) Determinants of behaviour, and 3) Preference, opportunities, and barriers.

In Chapter 6, we showed that lifestyle change is possible in CRC survivors with cancer-related fatigue as we saw favourable lifestyle changes in the intervention group, while the control group did not show changes to the same extent. However, the six-month lifestyle program was not effective in reducing cancer-related fatigue or improving health-related quality of life. In Chapter 7, we showed that the person-centred lifestyle program did not result in changes in the secondary outcomes: physical fitness, hemoglobin levels and blood pressure among CRC survivors with cancer-related fatigue.

Based on the findings of this dissertation and evidence from previously conducted trials with CRC survivors, a change in lifestyle behaviour does not appear to result in less cancer-related fatigue among CRC survivors who completed treatment and who experience cancer-related fatigue. However, it is feasible to improve lifestyle behaviours among this group. This is beneficial as healthy dietary behaviours and sufficient physical activity are associated with lower all-cause mortality and CRC-specific mortality in CRC survivors.