Reproducibility of the diagnosis of small adenocarcinoma of the lung and usefulness of an educational program for the diagnostic criteria

Using 32 small adenocarcinomas of the lung including bronchioloalveolar carcinoma (BAC), the reproducibility of diagnosis by the modified diagnostic criteria for small adenocarcinoma (Cancer 75; 2844, 1995) and the effectiveness of an educational program for 27 volunteer general pathologists were examined. The average coincidence rate of the diagnosis before and after the program was 42.4% and 56.6%, respectively. The coincidence rate after the program was significantly higher than that before the program (P < 0.05). In contrast, the average coincidence rate of six lung cancer specialists was 71.4%, and this was significantly higher than that for general pathologists after the program (P < 0.05). When the cases were divided into two groups (in situ adenocarcinoma (BAC and BAC with alveolar collapse) and early invasive adenocarcinoma), the average coincidence rate for the general pathologists after the program increased to 85.3%, which was significantly higher than that before the program (80.3%; P < 0.05). The rate for the specialists was 89%, which was higher than that for the general pathologists after the program but not significantly so. This trial was thought to provide a theoretical background for the histological diagnosis of peripheral type adenocarcinoma of the lung and to justify the existing diagnostic criteria.