Long-term urinary toxicity after 3-dimensional conformal radiotherapy for prostate cancer in patients with prior history of transurethral resection.

PURPOSE: To report on the long-term urinary morbidity among prostate cancer patients with a prior history of a transurethral resection of the prostate (TURP) treated with high-dose 3-dimensional conformal radiotherapy (3D-CRT). METHODS AND MATERIALS: Between 1988 and 1997, 1100 patients with clinically localized prostate cancer were treated with 3D-CRT. Of these, 120 patients (8%) were identified as having had a prior TURP and are the subjects of this analysis. The median age was 71 years (range: 49-83 years). The clinical stages of the patients were T1c: 33 (28%); T2a: 38 (32%); T2b: 15 (13%); and T3: 34 (27%). Neoadjuvant androgen ablation therapy was given to 39 (33%). The median radiation dose prescribed to the planning target volume was 75.6 Gy (range: 64.8-81 Gy). The median elapsed time from TURP to initiation of 3D-CRT was 69 months (range: 4-360 months). The median follow-up time was 51 months (range: 18-109 months).
RESULTS: Five patients of the 120 with a prior history of TURP (4%) developed a urethral stricture after 3D-CRT which was corrected with dilatation. The 5-year actuarial likelihood of >/= Grade 2 late urinary toxicities was 9%. No Grade 4 urinary toxicities were observed in this group of patients. Among 110 patients who were completely continent of urine prior to 3D-CRT, 10 (9%) developed stress incontinence requiring 1 pad daily for protection or experienced occasional leakage (not requiring pad protection). The 5-year incidence of >/= Grade 1 stress incontinence was 18% in patients who developed acute >/= Grade 2 GU symptoms during the course of 3D-CRT compared to 7% for patients who experienced Grade 1 or no acute urinary symptoms (p = 0.05). The radiation dose (>/=75.6 Gy vs. <75.6 Gy), the number of prior TURP procedures, or the volume of resected tissue at the time of TURP had no significant impact on the long-term urinary morbidity outcome. A multivariate analysis demonstrated that the presence of Grade 2 acute urinary symptoms was the only predictor of >/= Grade 1 stress incontinence after 3D-CRT in this group of patients.
CONCLUSIONS: Despite prior TURP, the incidence of >/= Grade 3 urinary toxicities is low. Nevertheless, especially among patients with a prior history of TURP who experience Grade 2 acute urinary symptoms during radiation treatment, a higher risk of stress incontinence is observed.