Physical activity patterns after diagnosis and survival of prognostic colorectal cancer subgroups.

BACKGROUND: Physical activity (PA) is associated with improved overall survival (OS) among colorectal cancer (CRC) patients, but research on PA changes after diagnosis remains limited. This study examines associations between OS and changes in PA from CRC diagnosis onward, across stage- and treatment-related subgroups. METHODS: Data were analyzed from patients in two large CRC cohorts (PLCRC and COLON) enrolled between August 2010 and December 2022 (follow-up until February 1st, 2024). This included 3395 stage I-IIA patients who underwent surgery only, 2406 stage IIB/C-III patients who received (neo-)adjuvant therapy, and 669 metastatic CRC (mCRC) patients. PA was assessed via the validated SQUASH questionnaire at diagnosis (T0), and at 6, 12, and 24 months post-diagnosis (T6 to T24). Moderate-to-vigorous-intensity recreational activity was quantified by calculating Metabolic Equivalent of Task (MET) hours per week. Associations with OS were examined for change (active [tertile 2 and 3] vs inactive [tertile 1]) between timepoints using multivariable Cox proportional hazards models. RESULTS: Among surgery-only patients, change from inactivity to activity between T0 and T6 was significantly associated with OS (HR = 0.58, 95% CI = 0.35 to 0.96). For (neo-)adjuvantly treated patients, significant associations were observed between T6 and T12 (HR = 0.53, 95% CI = 0.31 to 0.90). Among mCRC patients, a significant association was observed between T6 and T12 (HR = 0.53, 95% CI = 0.29 to 0.99). CONCLUSION: Changing from inactivity to activity is significantly associated with prolonged survival during the early months post-diagnosis for surgery-only CRC patients, and later for those undergoing (neo-)adjuvant therapy or with metastatic disease. Validation is warranted in interventional studies.