Optimal number of endoscopic biopsies in diagnosis of advanced gastric and colorectal cancer.

Endoscopic biopsy is necessary to confirm a histopathologic diagnosis. Currently, 6 to 8 biopsies are recommended for diagnosis of a suspected malignant lesion. However, multiple biopsies may result in several problems, such as an increased risk of bleeding, procedure prolongation, and increased workload to pathologists. The aim of this study was to clarify the optimal number of endoscopic biopsy specimens required in diagnosis of advanced gastrointestinal cancer. Patients who were diagnosed with advanced gastrointestinal cancer during endoscopy were included. Five specimens were obtained sequentially from viable tissue of the cancer margin. Experienced pathologists evaluated each specimen and provided diagnoses. A total of 91 patients were enrolled. Fifty-nine subjects had advanced gastric cancer, and 32 had advanced colon cancer. Positive diagnosis rates of the first, second, and third advanced gastric cancer specimens were 81.3%, 94.9%, and 98.3%, respectively, while positive diagnosis rates of advanced colon cancer specimens were 78.1%, 87.5%, and 93.8%. Further biopsies did not increase positive diagnosis cumulative rates. This study demonstrated that three specimens were sufficient to make correct pathologic diagnoses in advanced gastrointestinal cancer. Therefore, we recommend 3 or 4 biopsies from viable tissue in advanced gastrointestinal cancer to make a pathologic diagnosis during endoscopy.