Is T1G3 bladder cancer having a definite muscle layer in TUR specimens a highly progressive disease?

Patients with T1G3 bladder cancer are at high risk of progression to muscle-invasive cancer, and early cystectomy is considered as a treatment option in this particular situation. On the other hand, understaging of T1G3 bladder cancer has been gradually proven as second or repeat transurethral resection (TUR) has been widely applied. To evaluate the real rate of progression, we investigated the prognosis of T1G3 bladder cancer in which a muscle layer was histologically confirmed in the TUR specimens.

We retrospectively reviewed 48 patients with primary T1G3 bladder cancer in which a muscle layer in the TUR specimens was confirmed between 1990 and 2006 in our institute. We investigated recurrence and progression in 45 patients, excluding 3 who were immediately treated with radical cystectomy. Fifteen and 12 patients received intravesical treatment with bacillus Calmette-Guérin (BCG) and anticancer agents just after TUR, respectively. The remaining 18 did not have any such treatment.

Recurrence and progression were observed in 21 (47%) and 3 patients (6.7%), respectively, during a median follow-up period of 42.1 months. The 3-year recurrence-free and progression-free survival rates were 54% and 91%, respectively. No significant differences were observed in the rates between the patients with and without BCG treatment in the study.

There is a possibility that the progression rate in patients with T1G3 bladder cancer is not as high as previously reported when only patients whose muscle layer was histologically confirmed were analyzed. An adequate technique for TUR that unmistakably collects the muscle layer may be important to predict the outcome accurately.