Obesity surgery and risk of colorectal and other obesity-related cancers: An English population-based cohort study

• Published in: Cancer epidemiology 2018-04, Vol.53, p.99-104
• Main Authors: Aravani, Ariadni, Downing, Amy, Thomas, James D., Lagergren, Jesper, Morris, Eva J.A., Hull, Mark A.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age; Aged; Aged, 80 and over; Bariatric surgery; Bariatric Surgery - adverse effects; Body mass index; Breast cancer; Cancer; Codes; Cohort analysis; Colon cancer; Colorectal cancer; Datasets; Digestive System Surgical Procedures - adverse effects; Endometrial cancer; Endometrium; Epidemiology; Female; Gastrointestinal surgery; Health risk assessment; Health risks; Hospitals; Humans; Incidence; Kidney cancer; Lung cancer; Male; Medical diagnosis; Medical research; Medicin och hälsovetenskap; Middle Aged; Mortality; Neoplasms - epidemiology; Neoplasms - etiology; Obesity; Obesity - complications; Obesity - surgery; Population; Population studies; Population-based studies; Postoperative Complications; Rectal cancer; Retrospective Studies; Risk; Risk Factors; Surgery; Sweden - epidemiology; Systematic review; Weight control; Womens health; Young Adult
• ISSN: 1877-7821; 1877-783X; 1877-783X
• DOI: 10.1016/j.canep.2018.01.002

•The association between obesity surgery (OS) and cancer risk remains unclear.•Colorectal cancer (CRC) risk is increased in obese individuals.•No evidence of increased CRC risk after OS in this English population study.•Reduced breast cancer risk was apparent after OS.•Renal and endometrial cancer risk is elevated in obese patients. The association between obesity surgery (OS) and cancer risk remains unclear. We investigated this association across the English National Health Service. A population-based Swedish study has previously suggested that OS may increase the risk of developing colorectal cancer (CRC). A retrospective observational study of individuals who underwent OS (surgery cohort) or diagnosed with obesity, but had no OS (no-surgery cohort) (1997–2013) were identified using Hospital Episode Statistics. Subsequent diagnosis of CRC, breast, endometrial, kidney and lung cancer, as well as time ‘at risk’, were determined by linkage to National Cancer Registration & Analysis Service and Office of National Statistics data, respectively. Standardised incidence ratios (SIR) in relation to OS were calculated. 1 002 607 obese patients were identified, of whom 3.9% (n = 39 747) underwent OS. In the no-surgery obese population, 3 237 developed CRC (SIR 1.12 [95% CI 1.08–1.16]). In those who underwent OS, 43 developed CRC (SIR 1.26 [95% CI 0.92–1.71]). The OS cohort demonstrated decreased breast cancer risk (SIR 0.76 [95% CI 0.62–0.92]), unlike the no surgery cohort (SIR 1.08 [95% CI 1.04–1.11]). Increased risk of endometrial and kidney cancer was observed in surgery and no-surgery cohorts. CRC risk is increased in individuals diagnosed as obese. Prior obesity surgery was not associated with an increased CRC risk. However, the OS population was small, with limited follow-up. Risk of breast cancer after OS is reduced compared with the obese no-surgery population, while the risk of endometrial and kidney cancers remained elevated after OS.