Physical activity and sedentary behavior patterns after early-onset colorectal cancer diagnosis.

74 Background: Sedentary lifestyle and physical inactivity are established risk factors for colorectal cancer diagnosed among adults younger than age 50 years (early-onset CRC). However, patterns of physical activity (PA) and sedentary behavior (SB) in patients after an early-onset CRC diagnosis are less understood. Methods: The Reproductive Health After Cancer Diagnosis and Treatment (REACT) Study is a patient-partnered, cross-sectional study in cooperation with 23 community partners and patient advocates that recruited adults with a first primary cancer (diagnosis age: 18-49 years) over an 8-week period (October to December 2021). Patient-reported sociodemographic, cancer and cancer impact, PA and SB questions were prospectively collected via questionnaire. Frequency, duration and intensity of leisure-time, work-related and transportation-related PA were summed as minutes per week (min/wk). Time spent on SB was calculated by hours spent sitting on a typical day. Diagnosis age- and year-adjusted Spearman correlation coefficients were calculated between PA and SB by cancer treatment status. Results: A total of 131 patients were diagnosed with a first primary early-onset CRC between 2016 and 2021 (median [IQR] age, 40.0 [35-45] years; 82.4% female) in REACT. One hundred thirteen patients (86.3%) were concerned about their physical fitness or getting enough exercise after cancer diagnosis—of whom 62.8% (n=71 of 113) were somewhat or very concerned about their physical fitness/exercise. Among 80 patients with early-onset CRC and complete PA/SB data (86.3% female), 28.8% were not adherent to PA guidelines for aerobic activity (≥150 min/wk) and 56.3% reported long sedentary time (>6 hr/day). The proportion of patients across PA/SB groups also statistically significantly differed by treatment status among those diagnosed between 2019 and 2021 (p=0.049), but not between 2016 and 2018 (p=0.25). While PA was not significantly correlated with SB for early-onset CRC patients who were not actively undergoing treatment (r=-0.16, p =0.32), there was a statistically significant moderate inverse correlation between PA with SB among early-onset CRC patients under active cancer treatment (r=-0.58, p =0.004). Conclusions: One in every 2 early-onset CRC patients reported long sedentary time and one in every 4 early-onset CRC patients in this study did not meet the Physical Activity Guidelines for Americans. With over 80% of patients expressing concern about their physical activity and exercise after an early-onset CRC diagnosis, and differences in PA/SB patterns observed by treatment status, these findings warrant prospective, longitudinal studies of objectively-measured PA and SB among young patients in order to support tailored strategies (e.g., exercise prescriptions) that improve patient health and outcomes across the CRC continuum.