Rates of clinical tumor growth were studied in 47 patients with 50 primary advanced gastric cancers (Borrmann type; 1:9, 2:27, and 3:14 lesions). Long term serial changes in tumor size on X-ray films were evaluated retrospectively. Three lesions studied in this series showed fairly constant and simple exponential growth. For 46 tumors, the mean volume doubling time (VDT) was 8.7±2.6 months (5-17 months). These gastric cancers seemed to be moderately growing. Four tumors had VDTs of 26 to 34 months and might be slow growing. One lesion with mainly submucasal progression might not be rapid growing. Prediction of the size of missed lesions on X-ray films provides early detection of "gastritis-like-stomach cancers".