The use of oral antibiotics is linked to an increased colon cancer risk but a reduced risk of cancer in rectum, a large matched case-control study shows. The association between cancer and antibiotic use was seen when antibiotics had been used more than 10 years before diagnosis.
The cancer risk is dose-dependent for any antibiotics, although the risk increases most with anti-anaerobic antibiotics and especially penicillin. Penicillin significantly increases the risk of cancer in the proximal colon.
Zhang et al. Oral antibiotic use and risk of colorectal cancer in the United Kingdom, 1989-2012: a matched case-control study. Gut 2019; 0:1-8. Doi:10.1136/gutjnl-2019-318593