Factors predicting for urinary morbidity following 125iodine transperineal prostate brachytherapy

Abstract Purpose To assess factors related to the risk of acute urinary retention and other morbidity indices in patients undergoing transperineal seed implantation of the prostate. Materials and methods One hundred and seventy-three consecutive patients treated with 125 Iodine transperineal interstitial permanent prostate brachytherapy (TIPPB) were evaluated. Various demographic, pathological, symptomatic, urodynamic and dosimetric values were assessed in relation to the incidence of acute urinary retention as well as the International Prostate Symptom Score (IPSS) dynamics. Patients were routinely placed on α-blockade postimplant. Dosimetry was based on CT scan one month postimplant. Results Acute urinary retention developed in thirty-four patients (19.7%), at a median time of four days. Peak urinary flow rate was the only independent factor which varied significantly between those suffering retention and those not (median of 16 and 19.5 ml/s respectively, P =0.005). Median preimplant IPSS was 4.0, with a median peak of 16 at 3 months. Actuarial median time to return to baseline IPSS was at 15 months. The peak IPSS above preimplant levels was correlated significantly in multivariate analysis with the number of seeds implanted superior to the physician-nominated anatomical base level of the prostate ( P Conclusions In our series, preimplant urinary flow rate was the most important factor predictive of postimplant acute urinary retention. The patients' risk of having heightened IPSS change following implantation was correlated to a lower preimplant IPSS and an increased number of seeds implanted above the level of the prostatic base, possibly reflecting bladder base rather than urethral irritation in the development of acute urinary morbidity.