Prediction of bladder tumor relapse based on the risk factors and characteristics of the treatment

Objectives. To investigate the possibility of predicting recurrence of bladder tumors based on the clinical and morphological features of the disease and preoperative intravesical instillation of probiotic Aerococcus viridans 167. 190 patients operated for bladder tumors have been observed for a period from 1 to 73 months (mean 35.2 months). In 51 patients one single preoperative intravesical instillation of probiotic Aerococcus viridans 167 was added to a standard treatment. Reported cases of recurrence of tumors were used as a basis for the development of mathematical rules for predicting recurrences. These rules have been used to create a logistic regression and support vector machines. Of 190 patients, in 132 (69,5%) transitional cell carcinoma (TCC) in the stage Ta-T1, in 58 (30,5%) - transitional cell papilloma of the bladder (TCP) was identified. Recurrences were detected in 52 (27.4%) patients, mean time of observation was 14.7 (1-50 months). In patients with TCC recurrence was observed in 36 (37%) of 96 patients not treated with probiotic instillation vs 7 (19%) of 36 after probiotic use (p> 0,05). In TCP group no significant signs of the instillation influence of probiotics on the number of relapses were revealed. Classification rules that can predict the risk of recurrence of bladder tumors based on histological characteristics and application of probiotic were obtained. Preoperative instillation of probiotic Aerococcus viridans 167 in TCC TaT1 patients reduces the recurrence rate from 37% to 19% (p <0,05). Variables "Number of tumors" and "Maximum tumor size," and their relationship are informative prognostic parameters. The rules obtained may be recommended to follow up patients after surgery for timely distinguishing group of patients with increased risk of bladder tumor recurrence.