Can the outcome of transurethral resection of the prostate be predicted preoperatively?

To establish a formula for predicting the outcome of transurethral resection of the prostate using noninvasive parameters of preoperative evaluation.

The data of 54 men with a mean age of 57 years (range 43 to 78) were retrospectively analyzed. The International Prostate Symptom Score, quality-of-life score of the International Prostate Symptom Score questionnaire, maximal flow rate (Qmax) recorded during uroflowmetry, age, prostate volume calculated by transrectal ultrasonography, postvoid residual urine volume, and results of pressure-flow studies were evaluated to find a formula that would predict the outcome of transurethral resection of the prostate. The patients were evaluated by uroflowmetry, postvoid residual urine volume determination, and International Prostate Symptom Score questionnaire at 3 months postoperatively. Four different success criteria were investigated with the calculated equations.

According to the discriminant analysis, two new scores were calculated as S(1) = (0.169 x age) - (0.0075 x Qmax) and S2 = (0.168 x age) - (0.095 x Qmax) - (0.007 x detrusor pressure at Qmax). For the four success criteria, the optimal cutoff, obtained from the receiver operating characteristic curves of S(1) and S(2), was 8.83 and 9.21, respectively. A statistically significant difference was not found between S1 and S2. The S1 formula had a sensitivity between 71.8% and 85.2%, specificity between 71.4% and 86.7%, and positive predictive value between 72.2% and 92.9% for the four different criteria using two simple variables (Qmax of uroflowmetry and age).

Because urodynamic parameters did not add benefit to the formula consisting of age and Qmax of uroflowmetry with considerable sensitivity and specificity, performing urodynamic studies might not be useful for predicting the outcome of transurethral resection of the prostate.