Unavoidable Human Errors of Tumor Size Measurement during Specimen Attachment after Endoscopic Resection: A Clinical Prospective Study

OBJECTIVE Objective evaluation of resected specimen and tumor size is critical because the tumor diameter after endoscopic submucosal dissection affects therapeutic strategies. In this study, we investigated whether the true tumor diameter of gastrointestinal cancer specimens measured by flexible endoscopy is subjective by testing whether the specimen is correctly attached to the specimen board after endoscopic submucosal dissection resection and whether the size differs depending on the endoscopist who attached the specimen. METHODS Seventy-two patients diagnosed with early gastric cancer who satisfied the endoscopic submucosal dissection expanded-indication guideline were enrolled. Three endoscopists were randomly selected before every endoscopic submucosal dissection. Each endoscopist separately attached the same resected specimen, measured the maximum resection diameter and tumor size, and removed the lesion from the attachment board. RESULTS The resected specimen diameters of the 3 endoscopists were 44.5 ± 13.9 mm (95% Confidence Interval (CI): 23-67), 37.4 ± 12.0 mm (95% CI: 18-60), and 41.1 ± 13.3 mm (95% CI: 20-63) mm. Comparison among 3 groups (Kruskal Wallis H- test), there were significant differences (H = 6.397, P = 0.040), and recorded tumor sizes were 38.3 ± 13.1 mm (95% CI: 16-67), 31.1 ± 11.2 mm (95% CI: 12.5-53.3), and 34.8 ± 12.8 (95% CI: 11.5-62.3) mm. Comparison among 3 groups, there were significant differences (H = 6.917, P = 0.031). CONCLUSIONS Human errors regarding the size of attached resected specimens are unavoidable, but it cannot be ignored because it affects the patient's additional treatment and/or surgical intervention. We must develop a more precise methodology to obtain accurate tumor size. TRIAL REGISTRATION University hospital Medical Information Network UMIN No. 000012915.