International Session 35　　Parathyroid

Background] Patients with hypopharyngeal cancer frequently present with synchronous malignancies such as esophageal cancer.In esophageal cancer, synchronous colorectal cancer is also relatively common.At our institution, preoperative colonoscopy is routinely performed before extended resection for advanced hypopharyngeal cancer.This study aimed to evaluate the clinical significance of this practice.[Methods] We retrospectively reviewed patients with advanced hypopharyngeal cancer who underwent preoperative colonoscopy between September 2013 and December 2024.[Results] A total of 71 patients with hypopharyngeal cancer underwent preoperative colonoscopy.Colorectal tumors were detected in 25 patients (35． 3％) , including 6 cases of colorectal cancer(8． 5％) .Notably, 4 of the 6 colorectal cancers(66． 7％)were not detected on PET-CT.Clinical characteristics were compared between patients with and without colorectal lesions.[Conclusions] Preoperative colonoscopy identified a notable number of synchronous colorectal cancers in advanced hypopharyngeal cancer, indicating that colorectal cancer should be recognized as a potential synchronous malignancy in this population.