Diet and Physical Activity Interventions to Improve Outcomes in Colorectal Cancer Survivors: A Multicenter Randomized Controlled Trial in North Africa.

Abstract

The aim of this study is to evaluate the effectiveness of a culturally adapted lifestyle intervention that combines diet and physical activity (PA) in improving survival outcomes and quality of life among colorectal cancer (CRC) survivors in North Africa. A multicenter, randomized, controlled phase II trial with a 2 × 2 factorial design enrolled 300 nonmetastatic CRC survivors in remission across three oncology centers. Participants were randomly assigned into four groups: combined diet + PA, diet-only, PA-only, or usual care. Interventions were delivered for 12 months, with outcomes assessed at 24 months. Primary end points were changes in dietary behaviors and PA levels; secondary end points included disease-free survival (DFS), overall survival (OS), and quality of life (FACT-G). The primary end points were achieved, with significant improvements in moderate-to-vigorous PA and dietary behaviors at 12 and 24 months across all intervention groups compared with usual care (<i>P</i> < .001), with the greatest and most sustained effects observed in the combined diet and PA arm. At 24 months, the combined intervention group demonstrated a 75% reduction in recurrence risk (hazard ratio [HR], 0.25 [95% CI, 0.08 to 0.78]; <i>P</i> = .01) and an 82% reduction in mortality (HR, 0.18 [95% CI, 0.04 to 0.78]; <i>P</i> = .01) compared with usual care. Diet-only and PA-only arms showed favorable but nonsignificant trends. Quality-of-life scores (FACT-G) improved across all intervention groups, with the greatest gains in the combined intervention arm. Subgroup analyses revealed consistent effects across age, sex, comorbidity status, tumor site, and cancer stage. Structured, culturally adapted lifestyle interventions integrating diet and PA significantly enhance survival and quality of life in CRC survivors, with the greatest benefits observed in the combined intervention group.