Abstract 069: Healthy Lifestyle and Risk of Cardiovascular Disease Incidence and Mortality Among Survivors with Stages I-III Colorectal Cancer

Introduction: Colorectal cancer (CRC) is a prevalent cancer and a leading cause of cancer deaths in the US. CRC survivors have a high risk of developing cardiovascular disease (CVD), which accounts for nearly 20% of their total mortality, likely due to shared risk factors including lifestyle. Hypothesis: We hypothesized that maintaining a healthy lifestyle after a CRC diagnosis is associated with a lower risk of CVD incidence and mortality. Methods: We analyzed data from 2,737 survivors with stages I-III CRC in the Nurses’ Health Study and Health Professional Follow-up Study. A lifestyle score, ranging from 0 to 5, was calculated for participants based on diet quality, smoking status, alcohol intake, physical activity, and body mass index. We calculated cumulative averaged scores before and after CRC diagnosis and used Cox proportional hazards regression to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD incidence and mortality. We further examined changes in pre- and post-diagnostic lifestyle in relation to CVD outcomes and assessed potential effect modification by age, tumor characteristics, and medical history. Results: Over a median follow-up of 13.3 years after CRC diagnosis, we documented 449 incident CVD cases, including 201 coronary heart disease and 104 stroke cases, and 307 CVD-specific deaths. After adjustment for demographics, medical history, tumor characteristics, and pre-diagnostic lifestyle score, one unit increase in post-diagnostic score was associated with a 13% lower CVD incidence (HR [95% CI]: 0.87 [0.77-0.98]; p-trend: 0.03) and 29% lower CVD mortality (0.71 [0.61-0.83]; <0.0001). When stratified by tumor stage, the inverse association with CVD incidence was observed for stage I (0.74 [0.60-0.92]) but not stages II-III CRC (1.12 [0.93-1.35]; p-interaction: 0.005); whereas no differential associations were found for CVD mortality. Survivors who maintained a healthy lifestyle (score ≥4) pre- and post-diagnosis had a 28% lower risk of CVD incidence (0.72 [0.57-0.92]) and a 48% lower risk of CVD mortality (0.52 [0.39-0.70]) compared to those with a constantly poor lifestyle (score <4). Conclusions: In conclusion, a healthy lifestyle after CRC diagnosis was associated with a substantially lower risk of CVD incidence and mortality, highlighting the role of a healthy lifestyle in improving survivorship. These findings offer valuable insights for integrating lifestyle interventions into CRC oncology care.