(HealthDay News) — Individuals who undergo bariatric surgery may be at increased risk for developing colon cancer years later, according to a study published online Dec. 4 in the International Journal of Cancer.
Wenjing Tao, from the Karolinska University Hospital in Solna, Sweden, and colleagues compared the incidence of colorectal cancer for adults with obesity in Denmark, Finland, Iceland, Norway, or Sweden in 1980 to 2015 who had and had not undergone bariatric surgery.
The researchers found that 9.9 percent of the 502,772 cohort participants with an obesity diagnosis underwent bariatric surgery. After bariatric surgery, there was an increase in the overall standardized incidence ratio (SIR) of colon cancer (SIR, 1.56; 95 percent confidence interval [CI], 1.28 to 1.88), with SIRs higher ≥10 years after surgery. In surgical versus nonsurgical participants, the overall hazard ratio (HR) of colon cancer was 1.13 (95 percent CI, 0.92 to 1.39) and the HR was 1.55 (95 percent CI, 1.04 to 2.31) 10 to 14 years after bariatric surgery. The risk for rectal cancer was not significantly increased with bariatric surgery (SIR, 1.14; 95 percent CI, 0.83 to 1.52; HR, 1.08; 95 percent CI, 0.79 to 1.49); with longer follow-up periods, there was an increase in risk estimates.
“An increased risk of colorectal cancer following bariatric surgery might merit surveillance of patients undergoing such surgery,” the authors write.