Patient-reported long-term rectal function after permanent interstitial brachytherapy for clinically localized prostate cancer.

PURPOSE: To evaluate the effect of permanent interstitial brachytherapy with or without supplemental therapies on long-term rectal function using a patient-administered quality-of-life instrument.

METHODS AND MATERIALS: One hundred thirty four of the initial 219 prostate brachytherapy patients who remain alive and have participated in a prospective evaluation of rectal function were mailed the rectal function assessment score (R-FAS). Of the 134 patients, 3 have a colostomy because of colorectal cancer, 2 failed to respond, and 129 (99.2% of eligible patients) returned a completed R-FAS. R-FAS ranges from 0 to 27 with lower scores indicative of better bowel function. Median followup was 14 years. Multiple clinical, treatment, and dosimetric parameters were evaluated for impact on bowel function.

RESULTS

For the current cohort, R-FAS was 3.35, which was comparable to the 1999 (4.29), 2002 (3.92), and 2006 (4.00) surveys. In the 2011 survey, 10 (7.8%), 17 (13.1%), and 102 (78.3%) patients reported bowel function to be worse, improved, or unchanged after brachytherapy. No patient has developed a rectal ulcer or fistula. The number of preimplant bowel movements, tobacco, and diabetes mellitus correlated with R-FAS. Consistent with the previous thee surveys, patient's perception of overall rectal quality of life was inversely related to the use of supplemental external beam radiation.

CONCLUSIONS

Long-term rectal function after prostate brachytherapy is favorable with a small number of patients reporting deterioration in bowel function. The judicious use of supplemental external beam radiation with particular attention to rectal doses may further improve long-term function.