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.