Heavy, Consistent Alcohol Intake Increases Risk of Colorectal Cancer

The risk of colorectal cancer may increase with consistent heavy alcohol intake and higher average lifetime alcohol drinking, though cessation may reduce the risk of adenoma, according to a study published in Cancer.

Among the 12,327 patients in the trial who had a negative baseline colorectal cancer screen, 812 had an incident colorectal adenoma. Current drinkers with the highest average lifetime alcohol intake did not have higher adenoma risk when compared with those with the lowest average lifetime alcohol intake. An inverse association was noted for former drinkers who had an average lifetime alcohol intake of less than one drink per week (OR, 0.78; 95% CI, 0.59-1.02); notably, the association for nonadvanced adenoma reached statistical significance (OR, 0.58; 95% CI, 0.39-0.84). This effect was not modified or changed based on the patient’s sex (likelihood ratio test, p = .25).

With a median follow-up time of 15.4 years in 88,092 patients, 1679 incident colorectal cancer cases occurred. Regarding colorectal cancer risk, a positive association between current drinkers who had the highest average lifetime alcohol drinking compared with current drinkers who had the lowest average lifetime intake was observed in the multivariable-adjusted model, with 14 or more drinks per week compared with less than one drink (HR, 1.25; 95% CI, 1.01-1.53; P = .003). Further, a higher risk of rectal cancer was noted among current drinkers who consume 14 or more drinks per week vs those who drink less than 1 (HR, 1.95; 95% CI, 1.17-3.28). The positive HR estimate for 14 or more alcoholic drinks per week was strengthened in the control arm when stratified by trial arm (HR, 1.39; 95% CI, 1.06-1.82).

An inverse association for colorectal cancer risk was also observed between current drinkers who consume from seven to less than 14 drinks compared with current drinkers who consume less than 1 per week (HR, 0.79; 95% CI, 0.64-0.97). The strongest association for drinkers who consume from 7 to less than 14 drinks vs less than 1 drink was observed for distal colon cancer (HR, 0.64; 95% CI, 0.42-1.00; P for heterogeneity = .30), as well as in the screening arm (HR, 0.71; 95% CI, 0.51-0.98).

The effect of alcohol was not modified by sex (likelihood ratio test, p = .10). Both the overall and by trial arm HR estimates were similar when the first 2 years of follow-up were excluded and when body mass index was not adjusted for.

Heavy alcohol intake patterns correlated with demographic and lifestyle factors, such as male sex and current smoker status. Current, consistent heavy drinkers had 91% higher risk of colorectal cancer compared with current, consistent light drinkers (HR, 1.91; 95% CI, 1.17-3.12). Those who were moderate drinkers at some point in their life (HR, 0.95; 95% CI, 0.81-1.12), as well as former moderate-to-heavy drinkers (HR, 0.89; 95% CI, 0.69-1.15), did not have an increased risk of colorectal cancer.

“[W]e observed that current drinkers who had the highest, compared with the lowest, average lifetime intake and consistent heavy drinkers, compared with consistent light drinkers (below dietary guidelines), had higher risks of colorectal cancer, particularly for rectal cancer,” stated lead study author Caitlin P. O’Connell, MPH, from the Division of Cancer Epidemiology and Genetics of the Metabolic Epidemiology Branch at the National Institutes of Health, and coauthors, in the study with coinvestigators.¹

A total of 154,887 patients between the ages of 55 and 74 years, with no history of prostate, lung, colorectal, or ovarian cancers, were enrolled into the PLCO Cancer Screening Trial between 1993 and 2001. The final CRC analytic cohort included a total of 88,092 patients and the final incident adenoma analytic cohort included 12,327 patients.

Patients were assigned to either the screening arm of the trial (n = 77,443) and received flexible sigmoidoscopy at baseline and three years or five years later, or the control arm and received standard of care.

All patients completed a risk factor questionnaire at baseline, which identified demographic, medical, and lifestyle information. They also completed a dietary history questionnaire at baseline or approximately 3 years after baseline.

“Future research, including consortium efforts and new cohort studies with data on lifetime alcohol intake, is needed to strengthen evidence on the role of alcohol drinking reduction and cessation in the development of colorectal adenoma and colorectal cancer,” the authors concluded.

Reference

O’Connell CP, Berndt SI, Chudy-Onwugaje K, et al. Association of alcohol intake over the lifetime with colorectal adenoma and colorectal cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Cancer. 2026;132(3):e70201. doi:10.1002/cncr.70201