Late rectal function after prostate brachytherapy.

Abstract

Using a patient-administered quality of life instrument, to evaluate the effect of permanent prostate brachytherapy on late rectal function. One hundred eighty-nine prostate brachytherapy patients were mailed the Rectal Function Assessment Score (R-FAS), with a prestamped return envelope. The R-FAS consists of nine questions and a scoring range of 0-27, with higher scores indicative of poorer bowel function. One hundred eighty-seven (98.4%) surveys were returned. The median follow-up was 66.3 months (range 54-92 months). Clinical, treatment, and dosimetric parameters evaluated for bowel dysfunction included patient age, diabetes, hypertension, tobacco consumption, clinical T-stage, elapsed time since implant, prostate ultrasound volume, planning target volume, hormonal status, supplemental external beam radiation therapy (EBRT), isotope, average, median and maximum rectal doses, total implanted seed strength, values of the minimum dose received by 90% of the prostate gland (D(90)), and the percent prostate volume receiving 100%, 150%, and 200% of the minimum prescribed dose (V(100/150/200)). The R-FAS score for the evaluated cohort was 3.92, which represented a slight improvement from the 1999 survey score of 4.15 (p = 0.29). Of the evaluated clinical, treatment, and dosimetric parameters, the number of preimplant bowel movements, a history of tobacco consumption, and the median rectal dose correlated with the R-FAS. Although lower rectal doses were noted with Pd-103, isotope did not predict for bowel function. Only 12% (23/187) of patients reported their bowel function to be worse after implantation. Patient perception of overall rectal quality of life was inversely related to the use of supplemental EBRT (p = 0.007). Minor bowel changes are noted following prostate brachytherapy. The vast majority of patients did not report any deterioration in bowel function. In addition, the R-FAS continue to improve with time.