Systematic Review With Meta-analysis

Bariatric Surgery Reduces the Incidence of Hepatocellular Carcinoma

Daryl Ramai; Jameel Singh; Janice Lester; Shahab R. Khan; Saurabh Chandan; Nicola Tartaglia; Antonio Ambrosi; Gaetano Serviddio; Antonio Facciorusso


Aliment Pharmacol Ther. 2021;53(9):977-984. 

In This Article

Abstract and Introduction


Background: Obesity is a risk factor for non-alcoholic steatohepatitis (NASH) and increases the risk of several cancer types including cancers of the liver. Bariatric surgery can provide durable weight loss, but little is known about the later development of hepatocellular carcinoma (HCC) after surgery.

Aim: To determine whether bariatric surgery reduces the risk of HCC.

Methods: We performed a comprehensive literature search of major databases (from inception to November 2020) to identify studies which assess the incidence and risk of HCC following bariatric surgery. Pooled data were assessed using a random-effects model expressed in terms of odds ratio (OR), incidence rate ratio and 95% confidence interval (CI).

Results: Nine studies (two abstracts and seven full texts) were included for meta-analysis which involved 19 514 750 patients (18 423 546 controls and 1 091 204 bariatric patients). Pooled unadjusted odds ratio (OR) was 0.40 (95% CI: 0.28–0.57) which favoured bariatric surgery, though with high heterogeneity (I2: 79%). Using an adjusted model derived from matched cohorts (five studies) yielded an OR of 0.63 (95% CI: 0.53–0.75) with moderate heterogeneity (I2: 38%). The pooled rate/1000 person-years was 0.05 (95% CI: 0.02–0.07) in bariatric surgery patients and 0.34 (95% CI: 0.20–0.49) in the control group with an incidence rate ratio of 0.28 (95% CI: 0.18–0.42).

Conclusion: Bariatric surgery is associated with a decreased risk of HCC.


Obesity is defined as having a body mass index (BMI) over 30 kg/m2, and represents a growing global health epidemic.[1] Currently, more than half a billion of the world's adult population are obese.[2] In the United States, from 1999–2000 to 2017–2018, the age-adjusted prevalence of obesity has increased from 30.5% to 42.4%.[3] Obesity has been associated with increased risk of malignancy, systemic disease and mortality.[4]

Obesity increases the risk of gastrointestinal malignancies including liver, colorectal and oesophageal cancers.[5] Bariatric surgery is an evidence-based approach for treating obesity which offers long-lasting weight loss.[6] Bariatric surgery has also been shown to improve diabetes, fatty liver disease and cardiovascular conditions.[7–9] Currently, there are three main bariatric surgical procedures including gastric bypass, gastric banding and sleeve gastrectomy.[10]

However, there is limited knowledge on how bariatric surgery influences cancer risk, with some conflicting results.[11–14] We aim to assess the impact of bariatric surgery on the incidence of hepatocellular carcinoma (HCC) in comparison to a matched control group of patients who have not undergone such surgery using a systemic review and meta-analysis.