The significance of tumour grade in predicting disease progression in stage Ta transitional cell carcinoma of the urinary bladder

Objective To determine the significance of tumour grade in predicting disease progression in stage Ta transitional cell carcinoma (TCC) of the urinary bladder. Patients and methods From August 1975 to January 1991, 140 patients (121 men and 19 women, mean age 64.2 years, range 30-83) with stage Ta TCC of the urinary bladder were treated at the Veterans General Hospital-Taipei by transurethral resection and post-operative adjuvant intravesical chemotherapy. There were 48 patients (34%) with grade 1, 78 patients (56%) with grade 2 and 14 patients (10%) with grade 3 tumours. Disease progression and muscle invasion were assessed during a mean follow-up of 74.3 months and related to grade, urine cytology and the number and location of tumours. Results A total of 10 patients (7%) had tumour recurrence which invaded the muscle, of whom one had grade 1, six had grade 2 and three had grade 3 tumours. The patient with a grade 1 tumour developed muscle invasion within 16 months of surgery. The mean internal to the development of muscle invasion was 49.2 months in patients with grade 2 and 39.4 months with grade 3 tumour. In patients with stage Ta TCC, a grade 3 tumour was more likely to progress to muscle invasion (21%) than was a grade 1 (2.1%; P<0.05) or grade 2 (7.7%; P<0.05) tumour. One patient with a grade 2 and one patient with grade 3 tumour developed distant metastases without muscle invasion. Overall, the disease progression rate was 8.6% (12/140) in stage Ta TCC. Disease progression was more common with grade 3 (28.5%) than with grade 2 (9.0%; P<0.05) and grade 1 (2.1%; P<0.05) tumours. Conclusion Tumour grade may be used to predict disease progression after resection of stage Ta urinary bladder cancer. A higher grade of tumour was associated with a higher incidence of disease progression.