Urinary symptom flare following I-125 prostate brachytherapy

Abstract

Purpose: Although acute urinary morbidity after prostate brachytherapy has been well-documented, long-term effects have not been fully characterized. We describe a late complication of I-125 prostate brachytherapy we have termed urinary symptom flare.

Methods and materials: A total of 172 patients who underwent I-125 prostate brachytherapy between 1991 and 1998 completed a pretreatment and at least four follow-up International Prostate Symptom Score (IPSS) forms. Follow-up visits were made 1 month after implant and at 3- to 6-month intervals thereafter. Follow-up periods ranged from 12 to 106 months (median 41.5 months). The number of IPSS forms per patient ranged from 4 to 17 (median 6). A total of 32.6% of patients received both 3 months of neoadjuvant and 3 months of adjuvant hormonal therapy. Postimplant dosimetry revealed D90 values of 5578-25692 cGy (median 17290 cGy). The peak voiding score, indicating the time of the most severe urinary morbidity after brachytherapy, was defined as the highest rise in IPSS recorded after implantation. The nadir score was the lowest IPSS attained after the peak score, generally indicating a return to the patient's preimplant urinary function. A "flare" was defined as a rise in IPSS from the nadir score of at least five points, denoting a late exacerbation of urinary symptoms. Patients with a transient rise in PSA of 0.1 ng/ml or greater were considered to have a PSA bounce.

Results: The mean pretreatment IPSS for the study population was 7.5. The mean peak IPSS was 19.4 and occurred from 0.1 to 25 months (median 1.3 months) after the date of implant. The mean nadir IPSS was 6.7 and occurred from 1.6 to 61.6 months (median 14.3) after brachytherapy. A total of 35.5% of patients (61/172) have experienced a urinary flare of 5 or more points, as measured by the IPSS form. The mean "flare" IPSS was 16.4. The time to develop a flare ranged from 5.8 to 64 months (median 23.9 months). The actuarial risk of developing a flare was 21% by 2 years, 34% by 3 years, 38% by 4 years, and 47% by five years. In 72% of patients (44/61) who developed a flare, the flare subsided to baseline by the next follow-up visit. Of the remaining patients, 3% (2/61) reached a baseline value two follow-up visits later. In 25% of the patients (15/61) who experienced a flare, it occurred during their last follow-up visit. No single factor, including PSA (p = 0.9), stage (p = 0.9), use of hormone therapy (p = 0.9), implanted activity (p = 0.1), ultrasound volume (p = 0.4), dose (p = 0.4), seed number (p = 0.4), or needle number (p = 0.9), had a significant effect on the risk of developing a flare. There was a trend for younger patients (<or=65 vs. >65, p = 0.07) to experience the urinary flare.

Conclusions: Acute symptoms after I-125 prostate brachytherapy appear to peak 1 month after a prostate implant and return to their baseline values at 1 year. A transient late exacerbation of urinary symptoms is common and can occur in up to half of all patients by 5 years. There appears to be no statistically significant association between a late exacerbation in urinary symptoms and clinical or implant parameters.