Long-term rectal function after permanent prostate brachytherapy

Purpose: To evaluate the effect of prostate brachytherapy with or without supplemental therapies on long-term rectal function by means of a patient-administered quality-of-life instrument. Materials and Methods: As part of an ongoing prospective evaluation, 164 of an initial 209 patients who remain alive were mailed the Rectal Function Assessment Score (R-FAS) with a prestamped return envelope. R-FAS range from 0 to 27 with lower scores being indicative of better bowel function. Of the 162 eligible patients, 161 (99.4%) returned the survey. Median follow-up was 9.0 years (range 8.2-11.2 years). Clinical, treatment, and dosimetric parameters evaluated for bowel function included patient age, diabetes, hypertension, tobacco consumption, clinical T stage, elapsed time since brachytherapy, ultrasound volume, planning target volume, androgen deprivation therapy, supplemental external beam radiation, isotope, rectal dose, prostate D-100/D-150/D-200, and prostate D-90. Results: For the entire cohort, the current R-FAS was 3.59, which represented a nonstatistical improvement from prior surveys in 1999 (4.29) and 2002 (3.92) (P = 0.134). Only 16 patients (9.9%) reported bowel function to be worse after brachytherapy. Of the clinical, treatment, and dosimetric parameters evaluated, only the number of preimplant bowel movements, tobacco use, and diabetes correlated with R-FAS. Despite lower rectal doses with 103 Pd, isotope did not predict for bowel function. Consistent with prior surveys, patient perception of overall rectal quality of life was inversely related to supplemental external beam radiation (P = 0.027). Conclusion: Prostate brachytherapy adversely affects bowel function. However, in most patients the changes are minimal and slowly resolve with time. Overall rectal quality of life is inversely related to supplemental external beam radiation.