Risk of squamous cell carcinoma and adenocarcinoma of the esophagus in patients with Achalasia: A long-term prospective cohort study in Italy

INTRODUCTION: Epidemiological studies assessing relative risk and incidence rate of esophageal cancer in patients with achalasia are scarce. We performed a long-term prospective cohort study to evaluate the risk of both squamous cell carcinoma and adenocarcinoma of the esophagus in these patients. METHODS: Between 1973 and 2018, patients with primary achalasia were followed by the same protocol including upper endoscopy with esophageal biopsies. Standardized incidence ratios (SIRs) with 95% confidence interval (CI) were used to estimate the relative risk of esophageal cancer in patients with achalasia compared with the sex- and age-matched general population. RESULTS: A cohort of 566 patients with achalasia (46% men, mean age at diagnosis: 48.1 years) was followed for a mean of 15.5 years since the diagnosis of achalasia. Overall, 20 patients (15 men) developed esophageal cancer: 15 squamous cell carcinoma and 5 adenocarcinoma. The risk of esophageal cancer was significantly greater than the general population (SIR 104.2, 95% CI 63.7-161), and this for both squamous cell carcinoma (SIR 126.9, 95% CI 71.0-209.3) and adenocarcinoma (SIR 110.2, 95% CI 35.8-257.2). The excess risk was higher in men than women. Annual incidence rate of esophageal cancer was only 0.24% and was higher for squamous cell carcinoma (0.18%) than adenocarcinoma (0.06%). DISCUSSION: Patients with achalasia have an excess risk of developing both squamous cell carcinoma and adenocarcinoma of the esophagus; however, this prospective cohort study confirms that the annual incidence of esophageal cancer is rather low. These findings may have implications for endoscopic surveillance of patients with achalasia.