Metachronous Cancer Occurring after Endoscopic Resection of Superficial Esophageal Cancer

Esophageal cancer has a relatively high prevalence of local recurrence, which is associated with a poor prognosis. Superficial esophageal cancer has shown a metachronous recurrence rate of 2.6~35.8% with the cumulative overall 3-year and 5-year metachronous cancer incidence being 9.9~15.5% and 20.6~24.5%, respectively. In addition to recurrences in the remnant esophagus, second metachronous primary tumors have been reported to arise in 4.0~37.4% of esophageal cancer survivors. The second primary cancers arising after a diagnosis of esophageal cancer are most commonly detected in the head and neck area, followed by the lungs and stomach. The field cancerization theory explains the high prevalence of head and neck cancer among esophageal cancer patients. The reported risk factors for metachronous esophageal recurrences include scattered-type Lugol staining, circumferential endoscopic resection of the primary lesion, heavy alcohol use, smoking, inactive aldehyde dehydrogenase-2 genes, alcohol dehydrogenase-1B genes, and young age at diagnosis of the primary cancer. The risk factors for metachronous second primary tumors include heavy alcohol use, smoking, and a previous history of radiation therapy. Consequently, periodic follow-up endoscopy using narrow-band imaging is essential for the screening of metachronous esophageal cancers and second primary tumors after endoscopic resection for superficial esophageal cancer.