Clinical significance of the "palpable mass" in patients with muscle-infiltrating bladder cancer undergoing cystectomy after pre-operative radiotherapy. Between 1976 and 1985, 132 patients with T2/T3/T4a bladder cancer underwent cystectomy after pre-operative radiotherapy (46 Gy: 67 patients; 20 Gy: 65 patients). After a median time of 41 months, 62 patients were alive; 51 had died from recurrent bladder cancer and 19 from intercurrent disease without recurrence of their malignancy. Distant metastases developed in 40 patients, accompanied in 5 cases by local recurrence. Local recurrence was the first sign of relapse in 11 patients. In 3 patients the localisation of the relapse remained unknown. The corrected 5-year survival rate was 60%. T category and a palpable bladder tumour were independent pre-treatment prognostic factors in a Cox regression analysis, together with the interval between initial diagnosis and cystectomy. The presence of a palpable tumour before the start of treatment was associated with a particularly poor prognosis in T3/T4a tumours, whereas the survival of patients with non-palpable T3/T4a tumours was similar to that of patients with T2 bladder cancer. Another important prognostic factor was post-irradiation stage reduction (no residual muscle infiltration in the cystectomy specimen). Significantly more patients with non-palpable bladder tumours experienced post-radiation stage reduction than did those with a palpable tumour. However, the prognostic value of stage reduction was statistically significant only in patients with palpable bladder tumours. 