SIGNIFICANCE OF INVASION TO THE MUSCULARIS MUCOSAE ON THE PROGRESSION OF SUPERFICIAL BLADDER-CANCER

Objective. We tried to determine the significance of invasion to the muscularis mucosae on the progression of superficial bladder cancer. Methods. We subclassified superficial bladder cancer showing lamina propria invasion into two groups: with (pT1b) or without cancer invasion to or near the muscularis mucosae (pT1a). Results. Of 164 bladder cancers, 76 showed no lamina propria invasion and 88 did. In the tumors with lamina propria invasion, 60 were diagnosed as pT1a and 28 as pT1b. The progression rate of pT1b cancer (53.5%) was significantly higher than that of pT1a cancer (6.7%) (P < 0.01). Regardless of size, number, or grade of tumor, the progression rate of pT1b cancer was significantly higher than that of pT1a cancer (P < 0.01). Conclusions. We stress that patients with superficial cancer invading to or near the muscularis mucosae should be followed up carefully after transurethral resection.