Esophageal achalasia: a risk factor for carcinoma. A systematic review and meta-analysis.

Achalasia of the cardia is associated with an increased risk of esophageal carcinoma. The real burden of achalasia at the malignancy genesis is still a controversial issue. Therefore, there are no generally accepted recommendations on follow-up evaluation for achalasia patients. This study aims to estimate the risk of esophageal adenocarcinoma and squamous cell carcinoma in achalasia patients. We searched for association between carcinoma and esophageal achalasia in databases up to January 2017 to perform a systematic review and meta-analysis. A total of 1,046 studies were identified from search strategy, of which 40 were selected for meta-analysis. A cumulative number of 11,978 esophageal achalasia patients were evaluated. The incidence of squamous cell carcinoma was 312.4 (StDev 429.16) cases per 100,000 patient-years at risk. The incidence of adenocarcinoma was 21.23 (StDev 31.6) cases per 100,000 patient-years at risk. The prevalence for esophageal carcinoma was 28 carcinoma cases in 1,000 esophageal achalasia patients (CI 95% 2, 39). The prevalence for squamous cell carcinoma was 26 cases in 1,000 achalasia patients (CI 95% 18, 39) and for adenocarcinoma was 4 cases in 1,000 achalasia patients (CI 95% 3, 6).The absolute risk increase for squamous cell carcinoma was 308.1 and for adenocarcinoma was 18.03 cases per 100,000 patients per year. To the best of our knowledge, this is the first meta-analysis estimating the burden of achalasia as an esophageal cancer risk factor. The high increased risk rate for cancer in achalasia patients points to a strict endoscopic surveillance for these patients. Also, the increased risk for developing adenocarcinoma in achalasia patients suggests fundoplication after myotomy, to avoid esophageal reflux and Barret esophagus, a known risk factor for adenocarcinoma.