Abstract
We evaluated the optimal biopsy rate during a multicenter endoscopic screening for gastric cancer. According to our definition, the optimal biopsy rate is one in which the number of misdiagnosed cancers is low (i.e., cancer detection rate is high) and the screening efficiency is highest (i.e., the positive predictive value is highest). By analyzing 17,280 cases examined at institutions in Kanazawa in 2008 and 2009, the cases were classified according to the biopsy rates, which were divided into the following 5 ranges: <5%, ≥5 to <10%, ≥10 to <15%, ≥15 to <20%, and ≥20%.
The cancer detection rate and positive predictive value (PPV) according to the biopsy rates were as follows: 0.23% and 9.18% (biopsy rate, <5%), 0.36% and 5.16% (≥5 to <10%), 0.58% and 4.92% (≥10 to <15%), 0.32% and 2.00% (≥15 to <20%), and 0.59% and 2.21% (≥20%), respectively.
Generally, when the biopsy rate is higher, the PPV is lower, but the cancer detection rate is also higher. In this study, we found when the biopsy rate was increased beyond the ≥10 to <15%, the cancer detection rate did not increase: the highest PPV among the 3 higher ranges was found at biopsy rate ≥10 to <15%, therefore the optimal biopsy rate was found to be ≥10 to <15%.
