Pathophysiology and Natural History of Anorectal Sequelae Following Radiation Therapy for Carcinoma of the Prostate

Purpose To characterize the prevalence, pathophysiology, and natural history of chronic radiation proctitis 5 years following radiation therapy (RT) for localized carcinoma of the prostate. Methods and Materials Studies were performed in 34 patients (median age 68 years; range 54-79) previously randomly assigned to either 64 Gy in 32 fractions over 6.4 weeks or 55 Gy in 20 fractions over 4 weeks RT schedule using 2- and later 3-dimensional treatment technique for localized prostate carcinoma. Each patient underwent evaluations of ( 1 ) gastrointestinal (GI) symptoms (Modified Late Effects in Normal Tissues Subjective, Objective, Management and Analytic scales including effect on activities of daily living [ADLs]); ( 2 ) anorectal motor and sensory function (manometry and graded balloon distension); and ( 3 ) anal sphincteric morphology (endoanal ultrasound) before RT, at 1 month, and annually for 5 years after its completion. Results Total GI symptom scores increased after RT and remained above baseline levels at 5 years and were associated with reductions in ( 1 ) basal anal pressures, ( 2 ) responses to squeeze and increased intra-abdominal pressure, ( 3 ) rectal compliance and ( 4 ) rectal volumes of sensory perception. Anal sphincter morphology was unchanged. At 5 years, 44% and 21% of patients reported urgency of defecation and rectal bleeding, respectively, and 48% impairment of ADLs. GI symptom scores and parameters of anorectal function and anal sphincter morphology did not differ between the 2 RT schedules or treatment techniques. Conclusions Five years after RT for prostate carcinoma, anorectal symptoms continue to have a significant impact on ADLs of almost 50% of patients. These symptoms are associated with anorectal dysfunction independent of the RT schedules or treatment techniques reported here.