307. A REVIEW OF 31 SUPERFICIAL ESOPHAGEAL CANCER CASES WITHOUT HISTORY OF HABITUAL DRINKING OR SMOKING OBSERVED IN OUR HOSPITAL

In Japan, alcohol consumption, smoking, and genetic an aldehyde dehydrogenase 2 polymorphisms are risk factors for most esophageal squamous cell carcinomas(ESCC). However, only a limited number of cases have been observed without these risk factors in daily practice. This study aimed to evaluate the endoscopic findings of 31 lesions in 29 patients with ESCC who underwent endoscopic submucosal dissection (ESD) at our hospital without a history of habitual alcohol consumption or smoking (hereafter referred to as ‘risk factors’). Patients and Methods: We retrospectively examined the endoscopic findings, final diagnoses, and patient and lesion backgrounds of 31 lesions from 29 patients of ESCC without risk factors who underwent ESD from January 2017 to December 2022 at our hospital. A total of 27 women and two men, median age 72 (44–87) years, were included; 10 patients were on proton pump inhibitors, 12 patients had a history of cancer, and 12 patients had a family history of cancer in the first degree. Additionally, three patients had multiple heterochronic lesions, one patient had a speckled esophagus, and two patients had grade B gastroesophageal reflux disease according to the revised Los Angeles classification. Occupied site; Ut/Mt/Lt = 4/24/3, circumferential; anterior/posterior/left/right wall = 0/16/10/5, macroscopic type; 0-IIa/0-IIb/0-IIc/mixed type = 4/10/15/2, median lesion length 17(5–45) mm, wall depth; EP/LPM/MM/SM1 = 11/18/1/1/1, all vascular invasions were negative. A total of 22 lesions had white-tone mucosa on their surface, suggesting superficial keratinization or hyperkeratinization. The lesions were diverse in shape. Additionally, seven lesions were observed which tended to run longitudinally with long axial lengths, all located on the posterior wall of Mt, and white adherent material was observed in six lesions. Iodine staining was performed in 30 lesions, all of which were unstained, and six of them had indistinct borders with inflammatory changes in the background. A total of three patients had synchronous/heterochronic multiple esophageal cancers. The white adherents running longitudinally in the posterior wall of the Mt and its white tone in patients with no risk factors suggest the possibility of previously unrecognized lesions and the need for close endoscopic examination, along with iodine staining and biopsy.