The Role of Long-Term Physical Activity in Relation to Cancer-Related Health Outcomes: A 12-Month Follow-up of the Phys-Can RCT

PURPOSE: While moderate-to-vigorous intensity physical activity (MVPA) is associated with various health improvements shortly after completion of exercise interventions, it remains unclear which health benefits can be expected when MVPA levels are maintained in the long term in cancer survivors. We aimed to assess the associations of (1) MVPA level at 12-month follow-up and (2) long-term MVPA patterns (from immediately post-intervention to 12-month follow-up) with different cancer-related health outcomes. METHODS: In the Physical training and Cancer (Phys-Can) RCT, 577 participants diagnosed with breast (78%), prostate (19%), or colorectal (3%) cancer were randomized to 6 months of exercise during curative cancer treatment. Accelerometer-assessed physical activity and outcome data (ie, cancer-related fatigue, health-related quality of life [HRQoL], anxiety and depression, functioning in daily life, cardiorespiratory fitness, sedentary time and sleep) were collected immediately post-intervention and at 12-month follow-up. Based on the sample’s median of MVPA immediately post-intervention (65 minutes/day) and the changes between the 2 measurement points, 4 categories with different long-term MVPA patterns were created: High & Increasing, High & Decreasing, Low & Increasing, and Low & Decreasing. Multiple linear regression analyses were performed for the analyses. RESULTS: A total of 353 participants were included in the analyses. At 12-month follow-up, a higher MVPA level was significantly associated with lower fatigue in 3 domains (general fatigue [β = −.33], physical fatigue [β = −.53] and reduced activity [β = −.37]), higher cardiorespiratory fitness (β = .34) and less sedentary time (β = −.35). For long-term MVPA patterns, compared to the participants in the “Low & Decreasing” category, those in the “High & Increasing” category reported significantly lower fatigue in 3 domains (general fatigue [β = −1.77], physical fatigue [β = −3.36] and reduced activity [β = −1.58]), higher HRQoL (β = 6.84) and had less sedentary time (β = −1.23). CONCLUSION: Our results suggest that long-term physical activity is essential for improving health outcomes post-intervention in cancer survivors. Cancer survivors, including those who reach recommended MVPA levels, should be encouraged to maintain or increase MVPA post-intervention for additional health benefits. TRIAL REGISTRATION: NCT02473003 (10/10/2014)