Post-diagnosis dietary and lifestyle factors and mortality outcomes among colorectal cancer patients: a meta-analysis

Background While dietary and lifestyle factors are well-studied for colorectal cancer (CRC) prevention, less evidence exists on their impact on CRC survival. Methods PubMed and Embase were searched from inception to September 2024. Summary relative risk (SRR) and 95% confidence interval (CI) were estimated using the DerSimonian-Laird random-effects model. Results Lower all-cause mortality was observed with unprocessed red meat (SRR 0.74, 95%CI 0.57-0.94), whole grains (SRR 0.77, 95%CI 0.66-0.90), coffee (SRR 0.65, 95%CI 0.55-0.77), milk (SRR 0.82, 95%CI 0.71-0.93), low-fat dairy (SRR 0.77, 95%CI 0.64-0.94), total calcium (SRR 0.76, 95%CI 0.61-0.94), alcohol intake under 45 g/day (J-shaped association), and physical activity (SRR 0.55, 95%CI 0.44-0.69). Higher all-cause mortality was observed with refined grains (SRR 1.55, 95%CI 1.03-2.33), high-fat dairy (SRR 1.34, 95%CI 1.05-1.71), smoking (current (SRR 1.49, 95%CI 1.24-1.78), former (SRR 1.18, 95%CI 1.04-1.34)), and television watching (SRR 1.28, 95%CI 1.06-1.55). Risk increased linearly with body mass index (BMI) greater than 27 kg/m2, but also increased towards lower BMI. For CRC-specific mortality, most of the results were largely consistent, with calcium supplement showing an inverse association (SRR 0.66, 95%CI 0.47-0.94). Conclusions Factors related to CRC survival share differences as well as similarities with established factors related to CRC prevention. To optimize CRC survival, CRC patients may be recommended to adopt a diet rich in whole grains, coffee, milk, and dietary calcium; but to avoid excessive alcohol, refined grains, high-fat dairy, sugar sweetened beverage, smoking, and sedentary lifestyle; and to engage in regular physical activity while maintaining a healthy weight.