Oesophageal and Gastric Malignancies after Bariatric Surgery: A Retrospective Global Study

ABSTRACT Background Bariatric surgery can influence the presentation, diagnosis, and management of gastrointestinal cancers. Oesophago-Gastric (OG) malignancies in patients who have had a prior bariatric procedure have not been fully characterised. Objective To characterise OG malignancies after bariatric procedures. Setting University Hospital, United Kingdom. Methods We performed a retrospective, multi-centre observational study of patients with OG malignancies after bariatric surgery to characterise this condition. Results This study includes 170 patients from 75 centres in 25 countries who underwent bariatric procedures between 1985 and 2020. At the time of the bariatric procedure, the mean age was 50.2 ± 10 years and the mean weight 128.8 ± 28.9 kg. Females comprised 57.3% (n=98) of the population. Most (n=64) patients underwent a Roux-en-Y Gastric Bypass (RYGB) followed by Adjustable Gastric Band (AGB) (n = 46) and Sleeve Gastrectomy (SG) (n = 43). Time to cancer diagnosis after bariatric surgery was 9.5 ± 7.4 years and mean weight at diagnosis was 87.4 ± 21.9 kg. The time lag was 5.9 ± 4.1 years after SG compared to 9.4 ± 7.1 years after RYGB and 10.5 ± 5.7 years after AGB. One-third of patients presented with metastatic disease. The majority of tumours were adenocarcinoma (82.9%). Approximately 1 in 5 patients underwent palliative treatment from the outset. Time from diagnosis to mortality was under one year for most patients who died over the intervening period. Conclusions The OGMOS (Oesophago-Gastric Malignancies after Obesity/ Bariatric Surgery) study presents the largest series to date of patients developing OG malignancies after bariatric surgery and attempts to characterise this condition.