- Factors such as a diet high in processed meat and low in fiber, obesity, and physical inactivity have been linked to colorectal cancer risk.
- A recent study found that consistently drinking large amounts of alcohol and larger averages for lifetime alcohol consumption might also increase the risk for colorectal cancer.
- The results suggest another possible danger related to the heavy use of alcohol throughout one’s life.
Research continues to unfold regarding colorectal cancer and its relationship to alcohol use. A
The findings indicated that heavy lifetime drinking and heavy drinking in general may increase the risk of colorectal cancer.
Hence, the study suggests that quitting drinking may decrease the risk for non-advanced colorectal adenomas, highlighting a possible benefit of stopping alcohol consumption.
For this research, the authors used data from the prospective
The authors explain that they wanted to see how lifetime drinking related to risk for colorectal cancer and incidence of colorectal adenoma.
When they analyzed colorectal cancer, they included 88,092 participants. Researchers were more restrictive in whom they could include in their analysis of colorectal adenoma incidence. However, they excluded certain participants from both outcomes, such as those who had missing data on lifetime alcohol use.
Researchers evaluated lifetime alcohol use based on participants’ dietary history questionnaires. Participants provided information on how often they drank in four age ranges, such as their alcohol consumption when they were between the ages of 18 and 24. They could answer based on certain categories, such as answering that they drank six or more drinks per day. Participants also provided data on alcohol use over the past year.
Researchers categorized participants as current, former, or never drinkers and further divided participants into four categories for average lifetime drinking: “less than one, from one to less than seven, from seven to less than 14, and 14 or more drinks per week.”
Researchers also explain that they defined drinking patterns across adulthood. Past and current drinking was classified as light, moderate, or heavy based on sex-specific United States Dietary Guidelines, and drinking status was as never, former, or current.
In all, there were 812 cases of colorectal adenoma, among 12,327 participants, with additional data on where the tumors were located and their severity. Researchers did not find a link between current drinkers with the highest average lifetime alcohol intake and a greater risk for adenoma compared to current drinkers who had the lowest average lifetime alcohol intake.
However, the results suggested that people who quit drinking were at a lower risk for non-advanced adenomas, compared to current drinkers with the lowest average lifetime alcohol intake.
Regarding colorectal cancer, there were 1,679 cases that occurred, and the median follow-up time was 14.5 years. Results of the analysis suggested that current drinkers with the highest average lifetime alcohol intake were at a higher risk for colorectal cancer and, more specifically, rectal cancer than current drinkers who had the lowest average alcohol intake.
On the flip side, the results suggested that participants with an average lifetime alcohol intake of seven to less than 14 drinks weekly were actually at a lower risk for colorectal cancer compared to current drinkers with the lowest average lifetime alcohol intake, with the lowest risk being for distal colon cancer.
Participants who currently and consistently drank heavy amounts of alcohol “had 91% higher risk of CRC [colorectal cancer] compared with current, consistent light drinkers.”
The authors also suggest their findings indicate that current drinkers who drank at a moderate level at some point or points in their lives and former moderate-to-heavy drinkers did not have a higher risk for developing colorectal cancer.
Study author
“We found that compared to drinking <1 drink/week (“light”), drinking 14 or more drinks/week (2+ drinks/ day), on average throughout adulthood was associated with a higher risk of colorectal, namely rectal, cancer. In contrast, we observed no difference in colorectal cancer risk between average light drinkers and former drinkers, suggesting that risk may return to that of light drinkers even among former moderate to heavy drinkers.”
“Furthermore, we found that former drinkers, compared to light drinkers, were at lower risk of developing non-advanced colorectal adenomas,” she added.
One limitation of this research is participant reporting, such as alcohol intake, which may not be accurate. Researchers acknowledge that they expected some misclassification of participants’ reports on alcohol intake. It’s possible that cases of colorectal cancer were missed.
The study received funding from the National Institute of Health, the National Cancer Institute, and the Maryland Department of Health’s Cigarette Restitution Fund Program.
Researchers note that they had a limited number of adenoma cases and that any odds ratios based on data from less than 50 people “should be considered exploratory.”
Regarding the relationship with moderate alcohol intake, researchers acknowledge it could be because of residual confounding. Participants in the screening arm of the original trial also had screening in which polyps were removed and additional follow-up given, so researchers admit that screening is a possible intervention and could have affected the association. The association was stronger in the screening group.
The study also had some limitations because there were not enough data points, especially when the results were broken down into smaller groups for analysis.
The researchers further note that the participants from the PLCO study were mostly white and tended to have better health and education than individuals of similar ages in the U.S. general population, so the results may not be generalizable. There’s a possibility of chance findings because researchers conducted multiple tests. Finally, the researchers point out that because the study only observed people without controlling all factors, some hidden factors might still affect the results.
Richard Calderone, DO, MPH, FAAP, a board certified osteopathic physician specializing in general public health and internal medicine, who was not involved in the study, further noted the following limitations of the research to Medical News Today:
“This study found that moderate drinkers had a lower risk of distal colon cancer compared to light drinkers. The authors acknowledged that this may be due to residual confounding rather than a true biological benefit of alcohol, however this still creates a counseling challenge for our patients.”
Calderone also touched on one aspect the study may have overlooked: binge drinking.
“This study was designed to report average daily alcohol consumption over a week. It did not investigate/control for periods of abstinence combined with binge drinking (typically defined as 4 drinks for women and 5 drinks for men within a period of hours) during a given week. Therefore, the impact of the drinking pattern remains unknown, as constant, lower-dose exposures may pose a different risk when compared to limited, higher-dose exposures.”
— Richard Calderone, DO, MPH, FAAP
“This study design did not consider an individual’s alcohol intake prior to age 18. However, growing evidence demonstrates an increased risk of malignancy with early alcohol exposure—a potential influence not accounted for in these results,” he added.
The results do highlight the possible dangers of alcohol and imply the benefit of stopping alcohol use. Loftfield discussed the following clinical implications:
“Current advice on alcohol drinking for prevention of colorectal and other cancer types is to minimize intake or ideally to not drink at all. Our findings do not change this advice. However, our study provides new evidence indicating that drinking cessation may lower risk of non-advanced adenoma.”
More reasons to stop drinking alcohol“Furthermore, we found that colorectal cancer risk among former drinkers, including former moderate to heavy drinkers, as well as occasionally moderate or heavy drinkers, was similar to that among those who always consumed below recommended limits. Together, these findings support a role for drinking cessation and reduction in CRC [colorectal cancer] prevention.”
— Erikka Loftfield, PhD, study author
Anton Bilchik, MD, PhD, a surgical oncologist, chief of medicine, and Director of the Gastrointestinal and Hepatobiliary Program at Providence Saint John’s Cancer Institute in Santa Monica, CA, who was also not involved in the study, noted that “This study provides hope that it is never too late to reduce alcohol consumption since this can lead to fewer colon polyps and potentially cancer reduction.”
