Anorectal function after three- versus two-dimensional radiation therapy for carcinoma of the prostate.
OBJECTIVE
To compare the effects of (three-dimensional) 3D vs. two-dimensional (2D) radiation therapy (RT) for carcinoma of the prostate on the prevalence and pathophysiology of anorectal dysfunction.


METHODS
Anorectal symptoms, motility, sensory function, and anal sphincter morphology were evaluated before and up to 2 years after randomly assigned hypofractionated vs. conventionally fractionated RT in 67 patients (median age, 69 years; range, 54-82 years) with localized prostate carcinoma, using either a 3D (n = 29) or 2D (n = 38) treatment technique.


RESULTS
Anorectal symptoms increased 4 to 6 weeks after RT and persisted in both patient groups. At 2 years, abnormalities included increased stool frequency (55% vs. 53%, p = NS), urgency of defecation (72% vs. 47%, p < 0.05), fecal incontinence (28% vs. 26%, p = NS), and rectal bleeding (38% and 42%, p = NS). Anorectal motility and sensory function deteriorated after RT in both groups with reductions in basal anal pressures, anal pressures in response to squeeze, rectal compliance, and rectal volumes associated with the desire to defecate. External but not internal sphincter thickness changed in the treatment groups although in different directions. However no differences in motility or sensory function were detected between the groups. Baseline anorectal motility but not treatment technique and the hypofracionated schedule were of independent prognostic significance for anorectal motor dysfunction and rectal bleeding respectively at 2 years.


CONCLUSIONS
The prevalence and pathophysiology of anorectal dysfunction 2 years after RT for prostate carcinoma was largely independent of the treatment techniques used in this study.
Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide SA, Australia.
Eric K
EK
Yeoh
Richard H
RH
Holloway
Robert J
RJ
Fraser
Rochelle
R
Botten
Addolorata
A
Di Matteo
James W
JW
Moore
Mark N
MN
Schoeman
Dylan L
DL
Bartholomeusz
D000368:Aged; D000369:Aged, 80 and over; D001004:Anus Diseases / Q000175:diagnosis / Q000453:epidemiology; D001315:Australia / Q000453:epidemiology; D015897:Comorbidity; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000175:diagnosis / Q000453:epidemiology*; D020266:Radiotherapy, Conformal / Q000379:methods* / Q000706:statistics & numerical data*; D012002:Rectal Diseases / Q000175:diagnosis / Q000453:epidemiology*; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016896:Treatment Outcome