The association between colorectal cancer and prior antibiotic prescriptions: case control study

David Armstrong,Mark Ashworth,Chris Mcgee,Patrick White,Simon De Lusignan,Alex Dregan

doi:10.1038/s41416-019-0701-5

Abstract

BackgroundAntibiotic use over several decades is believed to be associated with colorectal adenomas. There is little evidence, however, for the effect of more recent antibiotic use on frequency of colorectal cancers.MethodsA case control study used the RCGP’s Research and Surveillance Centre cohort of patients drawn from NHS England. In all, 35,214 patients with a new diagnosis of colorectal cancer between 1 January 2008 and 31 December 2018 were identified in the database and were matched with 60,348 controls. Conditional logistic regression was used to examine the association between antibiotic prescriptions and colorectal cancer.ResultsA dose-response association between colorectal cancers and prior antibiotic prescriptions was observed. The risk was related to the number and recency of prescriptions with a high number of antibiotic prescriptions over a long period carrying the highest risk. For example, patients prescribed antibiotics in up to 15 years preceding diagnosis were associated with a higher risk of colorectal cancer (odds ratio (OR) = 1.90, 95% confidence intervals (CI), 1.61–2.19, p < 0.001).ConclusionsAntibiotic use over previous years is associated with subsequent colorectal cancer. While the study design cannot determine causality, the findings suggest another reason for caution in prescribing antibiotics, especially in high volumes and over many years.

Highlights

Antibiotic use over several decades is believed to be associated with colorectal adenomas
The probability of colorectal cancer increased from 47% (OR = 1.47, 95% confidence intervals (CIs), 1.41–1.54, p < 0.001) for one antibiotic prescription to 103% (OR = 2.03, 95% CI, 1.91–2.15, p < 0.001) after more than 10 prescriptions
The study reported here found a strong association between colorectal cancers and prior antibiotic prescriptions

Summary

Introduction

Antibiotic use over several decades is believed to be associated with colorectal adenomas. Analyses of faecal samples from patients with CRC compared with controls have identified over and under representation of some bacterial species in the cancer patients, though results have not been consistent.[8,9,10,11] The increasing list of potentially carcinogenic bacteria provides support for the hypothesis that the development of cancer is driven by mechanisms and/or pathways that are common to many bacterial groups rather than a single organism These observations have led to suggestions that targeted antibiotics, probiotics or prebiotics may have a role to play in CRC prevention or treatment.[12,13]

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Conclusion