Lower Gastrointestinal Morbidity and Management
During the weeks following the implant in a prostate cancer patient, there may be changes in bowel habits in the form of diarrhea or constipation, tenesmus, and rectal pressure 47, 57, 58. These symptoms generally respond to conservative symptomatic management. Late injury includes proctitis, rectal ulceration, fistula formation, and incontinence 59. The most common of these is proctitis, which often presents as a painless bleeding that is usually self-limited. Bleeding from proctitis presents late, about 1 to 2 years after implantation and may be exacerbated by constipation. Conservative management is recommended with stool softeners and local steroid creams or foams. Aggressive measures such as biopsies and laser treatments may precipitate ulceration and fistula formation and should be avoided whenever possible 47, 60.
The incidence of proctitis has been reported to range from 1% to 12% 47, 61. While the 12% proctitis rate reported by Wallner et. al. represents the early experience with CT-based implants, subsequent refinements of the technique indicate that proctitis rates have decreased to 2-6% 47, 62. In a review of 825 patients, Gelblum and Potters identified a 9.4% incidence of proctitis and 6.6% incidence of limited rectal bleeding at a mean time of 8 months post-implant. Four patients developed rectal ulceration with 2 of these patients having had rectal biopsies performed by a gastroenterologist 47. Synder et. al. reporting on Grade 2 proctitis following I-125 implants concluded that the incidence of proctitis was volume dependent for each dose studied 63. The 5 year actuarial risk of grade 2 proctitis was 5% if 1.3cc or less of the rectal volume received the prescription dose of 160Gy, and 17% for >1.3cc (p=0.001). Others have tried to correlate the risk of proctitis relative to the delivered dose and volume of the rectum with less success 61. While there is currently no specific recommendation on dose, intraoperative planning systems allow the operator to measure and limit the rectal dose during the case 31, 64.
The addition of external beam to permanent prostate brachytherapy may be a risk factor