Endoscopy biopsy is not efficiency enough for diagnosis of mucinous colorectal adenocarcinoma

BACKGROUND: Endoscopy biopsy (EB) is the standard diagnostic method for colorectal cancer (CRC), whereas its accuracy and efficiency in mucinous adenocarcinoma (MAC) initial diagnosis is unclear. METHODS: The initial EB and postoperative specimen (PS) pathological diagnosis of MAC from two centers were retrospectively collected and analyzed. The accuracy and efficiency of initial EB compared with PS pathological diagnosis were analyzed. The potential factors which would affect the initial EB diagnosis of MAC were analyzed. RESULTS: 280 and 78 eligible cases were enrolled in this study from two centers respectively. The initial EB diagnosis accuracy for MAC were 84.62% and 83.33%. However, among the cases of PS diagnosis with MAC, the diagnostic efficiency of initial EB was only 36.49% and 32.50% respectively. Lower tumor differentiation and more EB number were associated with an increased probability for the EB diagnosis of MAC, but only tumor differentiation was an independent diagnositic factor for EB in the two cohorts. CONCLUSIONS: The accuracy of initial EB with MAC is high, but the diagnostic efficiency was extremely low. Tumor differentiation and EB number were associated with the diagnosis efficiency of MAC before surgery. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12672-021-00443-4.