Following the American Cancer Society guideline for cancer survivors and obesity-related cancer survival.

In 2022, the American Cancer Society updated its guideline for cancer survivors. However, the impact of post-diagnosis adherence on mortality risk for those with obesity-related cancers remains unclear. This study followed nonsmoking participants from the Cancer Prevention Study-II Nutrition Cohort diagnosed with obesity-related cancers between 1992 and 2002 through 2020. Post-diagnosis adherence to ACS guidelines-body mass index (BMI), physical activity, diet, and alcohol consumption-was scored on a scale from 0 to 8. Cox proportional hazards regression models were used to calculate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Among 3,742 cancer survivors (mean age 67.6 years) with a median follow-up of 15.6 years, 2,430 deaths occurred. Survivors with a score of 6-8 had a 24% lower risk of all-cause mortality (HR, 0.76; 95% CI, 0.68-0.85), a 33% lower risk of cardiovascular disease mortality (HR, 0.67; 95% CI, 0.54-0.83), and a 21% lower risk of cancer-specific mortality (HR, 0.79; 95% CI, 0.64-0.97) compared to those with a score of 0-3. Higher BMI and physical activity scores were associated with lower all-cause mortality. Compared to survivors with a consistently low ACS guideline score (<5) both before and after diagnosis, those with a consistently high score (≥5) had lower all-cause and cardiovascular disease mortality. Additionally, survivors who improved their score from low to high had lower all-cause mortality. A lifestyle aligned with the ACS nutrition and physical activity guideline is associated with lower mortality risk among nonsmoking survivors of obesity-related cancers.