Factors affecting recurrence and progression in superficial bladder tumours.
Prognostic factors in superficial bladder tumours are highly correlated with each other. In this study, their relative importance is examined and grouping of patients in three different prognostic groups suggested. 576 patients (from EORTC protocols 30790 and 30782) were analysed. They have been followed from 3 months to 8.6 years with a median of 4 years. 76 patients developed an invasive tumour (> or = T2); the shortest time to invasion was 12 weeks, the longest was 6.6 years. Time from invasion to death ranged from 3 weeks to 4.4 years with a median of 2 years. Prognostic factors contributing to recurrence, invasion and survival were investigated: age, sex, size of largest tumour, number of tumours, T-category, G-grade, time from diagnosis (years), prior recurrence rate/year, site of involvement. The relative importance of these factors was measured by performing a multivariate analysis based on Cox's proportional hazards regression model. Based on the most important prognostic factors and their association with invasion and death, an index was computed reflecting the risk of both invasion and death due to malignant disease, respectively. The index was used to assign patients to one of three prognostic groups. Three main factors determined patient's prognosis: tumour size, G-grade and prior recurrence rate/year. The model coefficients for invasion were 0.51 (recurrence rate < 1/year, 1-3/year, > 3/year), 84 (grade 1, 2, 3), 0.48 (size < 1.5, 1.5-3, > 3 cm) and for death due to malignant disease 0.89 (recurrence rate), 0.73 (grade) and 0.44 (size), respectively. Risk groups are suggested based on the index. Additional treatment in patients with superficial transitional cell carcinoma of the bladder may be decided depending on the risk group to which the patient belongs.