Changes in Physical Activity and Mortality Risk among Korean Cancer Survivors: A Population-Based Cohort Study

The impact of changes in physical activity (PA) after cancer diagnosis on prognosis remains unclear. This study evaluated mortality risks according to changes in PA from prior to diagnosis to after diagnosis among cancer survivors.

This population-based retrospective cohort study used the Korean National Health Insurance Service database. The study included 215,191 participants (125,756 men and 89,435 women) diagnosed with cancer between 2009 and 2017. PA, measured as the total of various light-, moderate-, and vigorous-intensity activities, was assessed prior to and after diagnosis. Deaths were ascertained between 2009 and 2019. All-cause and cancer-specific mortality risks were assessed according to PA changes using Cox proportional hazards regression.

Following cancer diagnosis, active patients accounted for 63.30% of men and 55.29% of women, increasing from 54.04% and 43.35% prior to diagnosis. Compared with the consistently inactive group, all-cause mortality risks were significantly lower in patients who became active after diagnosis [adjusted HR (95% confidence intervals): men, 0.82 (0.79, 0.85); women, 0.87 (0.82, 0.93)] and in the consistently active group [men, 0.77 (0.74, 0.80); women, 0.81 (0.76, 0.86)]. Lower mortality risks were observed across cancer stages in men and localized/regional stages in women. PA and all-cause mortality had a dose-response association. PA was inversely associated with all-cause or cancer-specific mortality in men with gastric, colorectal, liver, and lung cancers and women with colorectal cancer.

Being physically active after diagnosis is associated with reduced all-cause mortality among cancer survivors in a dose-response manner, regardless of PA levels prior to diagnosis.

PA should be promoted as a standard component of cancer care to improve prognosis.