Do high radiation doses in locally advanced prostate cancer patients treated with 103Pd implant plus external beam irradiation cause increased urinary, rectal, and sexual morbidity?

Abstract

Purpose To investigate the morbidity of higher radiation doses in prostate cancer patients. Methods and Materials Five hundred eighty-five men treated with seed implantation and external beam irradiation were followed a median of 5 years (range, 2–11). Hormonal therapy (HT) of 9 months duration was used in 504 (86.2%) patients. The biologic effective dose (BED) was calculated using an α/ β of 2. Urinary incontinence (UI) and symptoms (IPSS) were prospectively collected. Rectal morbidity was scored according to the Radiation Therapy Oncology Group (RTOG) scale. Two BED dose groups of ≤220 Gy ( n = 449) and >220 Gy ( n = 136) were used. Comparisons of means were made by Student's t test, and the associations were tested by chi-square analysis (Pearson). Results Urinary retention developed in 36 (6.2%) and was not associated with BED or IPSS. Retention occurred more often with prostate volume >50 cc (17%, p = 0.001). The median change in urinary symptoms (IPSS) was 1. Sixty-one percent with high BED were more likely to have increased postimplant symptoms compared with 39% with lower BED ( p = 0.025; odds ratio [OR], 1.107; 95% confidence interval [CI], 1.10–1.21). UI occurred in 25 patients (4.3%) and was only associated with a postimplant transurethral resection of the prostate (TURP) ( n = 25), 16% vs. 2.3% for no TURP ( p = 0.001; OR, 8; 95% CI, 2.4–27). Of the 373 patients initially potent, 204 (54.7%) maintained potency. Impotence was only associated with age at implant ( p = 0.001) and HT ( p = 0.004). Sixty-two (10.6%) patients had Grade 1–2 and 4 patients had Grade 3–4 (0.7%, 2 ulcers and 2 fistulas) rectal complications. Three of the Grade 3/4 complications occurred with a dose ≤220 Gy. Conclusion A BED >220 Gy does not seem to increase morbidity.