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.

Hypofractionated versus conventionally fractionated radiotherapy for prostate carcinoma: final results of phase III randomized trial.

PURPOSE: To evaluate the long-term efficacy and toxicity of a hypofractionated (55 Gy in 20 fractions within 4 weeks) vs. a conventionally fractionated (64 Gy in 32 fractions within 6.5 weeks) dose schedule for radiotherapy (RT) for localized carcinoma of the prostate. METHODS AND MATERIALS: A total of 217 patients were randomized to either the hypofractionated (n=108) or the conventional (n=109) dose schedule. Most patients (n=156) underwent RT planning and RT using a two-dimensional computed tomography method. Efficacy using the clinical, radiologic, and prostate-specific antigen data in each patient was evaluated before RT and at predetermined intervals after RT until death. Gastrointestinal and genitourinary toxicity using the modified Late Effect in Normal Tissue-Subjective Objective Management Analytic (LENT-SOMA) scales was also evaluated before and at intervals after RT to 60 months. RESULTS: The whole group has now been followed for a median of 90 months (range, 3-138). Of the 217 patients, 85 developed biochemical relapse (nadir prostate-specific antigen level+2 µg/L), 36 in the hypofractionated and 49 in the conventional group. The biochemical relapse-free, but not overall, survival at 90 months was significantly better with the hypofractionated (53%) than with the conventional (34%) schedule. Gastrointestinal and genitourinary toxicity persisted 60 months after RT and did not differ between the two dose schedules. Multivariate analyses revealed that the conventional schedule was of independent prognostic significance, not only for biochemical failure, but also for an increased risk of worse genitourinary symptoms at 4 years. CONCLUSIONS: A therapeutic advantage of the hypofractionated compared with the conventional dose schedule for RT of prostate cancer was evident at 90 months in the present study.

Hypofractionated versus conventionally fractionated radiation therapy for prostate carcinoma: updated results of a phase III randomized trial.

PURPOSE: The aim of this study was to compare the toxicity and efficacy of radiation therapy (RT) for localized carcinoma of the prostate, using a hypofractionated (55 Gy/20 fractions/4 weeks) vs. a conventionally fractionated (64 Gy/32 fractions/6.5 weeks) dose schedule. METHODS AND MATERIALS: A total of 217 patients were randomized to either the hypofractionated (108 patients) or the conventional (109 patients) dose schedule, with planning with two-dimensional (2D) CT scan planning methodology in the majority of cases. All patients were followed for a median of 48 (6-108) months. Gastrointestinal (GI) and genitourinary (GU) toxicity was evaluated before RT and after its completion using modified late effects of normal tissue-subjective, objective, management, analytic (LENT-SOMA) scales and the European Organization for Research and Treatment of Cancer sexual function questionnaire. Efficacy of RT based on clinical, radiologic, and prostate-specific antigen data were also evaluated at baseline and after RT. RESULTS: Gastrointestinal and GU toxicity persisted 5 years after RT and did not differ between the two dose schedules other than in regard to urgency of defecation. However, 1-month GI toxicity was not only worse in patients with the hypofractionated RT schedule but also adversely affected daily activities. Nadir prostate-specific antigen values occurred at a median of 18.0 (3.0-54.0) months after RT. A total of 76 biochemical relapses, with or without clinical relapses, have occurred since; of these, 37 were in the hypofractionated and 39 in the conventional schedule. The 5-year biochemical +/- clinical relapse-free and overall survival was 55.9% and 85.3% respectively for all patients, and did not differ between the two schedules. CONCLUSIONS: Radiation therapy for prostate carcinoma causes persistent GI toxicity that is largely independent of the two dose schedules. The hypofractionated schedule is equivalent in efficacy to the conventional schedule.

Anorectal dysfunction increases with time following radiation therapy for carcinoma of the prostate.

OBJECTIVES: To characterize the prevalence and pathophysiology of anorectal dysfunction up to 2 yr following radiation therapy (RT) for localized carcinoma of the prostate. METHODS: Thirty-eight patients, median age 68 (range 60-82) yr with localized prostate carcinoma randomly assigned to one of two radiation dose schedules, underwent evaluation of the following variables of anorectal function before RT, as well as 4-6 wk and 1 and 2 yr after its completion: (1) symptoms, (2) anorectal motility, (3) anorectal sensory function, and (4) anal sphincteric morphology. RESULTS: There was a persistent increase in anorectal symptoms after RT. At 2 yr, bowel frequency, urgency, and fecal incontinence were increased in 50%, 47%, and 26% of patients, respectively. After RT, there were progressive reductions of (1) basal anal pressures, (2) anal pressures in response to squeeze and increased intra-abdominal pressure, (3) rectal compliance, and (4) rectal volumes associated with sensory perception and the desire to defecate. The thickness of the external anal sphincter increased with time after RT. No difference was observed between the patients in the two radiation dose schedules. CONCLUSIONS: Anorectal dysfunction following RT for prostate carcinoma is an underestimated cause of morbidity, which progresses with time. The prevalence and pathophysiology of anorectal dysfunction is similar after treatment with two commonly used radiation dose schedules.

Evidence for efficacy without increased toxicity of hypofractionated radiotherapy for prostate carcinoma: early results of a Phase III randomized trial.

PURPOSE: We performed a randomized trial to compare the GI and urogenital toxicity of radiotherapy (RT) for localized (confined to the organ), early-stage (T1-T2N0M0, TNM classification) carcinoma of the prostate, using a conventional (64 Gy in 32 fractions within 6.5 weeks) vs. a hypofractionated (55 Gy in 20 fractions within 4 weeks) schedule and to determine the efficacy of the respective treatment schedules. METHODS AND MATERIALS: This report is based on an interim analysis of the first 120 consecutive patients in this Phase III trial after a median follow-up of 43.5 months (range 23-62). RT planning was based on two-dimensional CT data, and the treatment was delivered using a three- or four-field 6-23-MV photon technique. GI and urogenital toxicity (symptom questionnaires incorporating the subjective elements of the late effects of normal tissues-subjective, objective, management, analytic classification of late effects and the European Organization for Research and Treatment of Cancer sexual function questionnaire) were evaluated before RT and 1 month, 1 year, and 2 years after RT completion. The efficacy of RT was assessed clinically (digital rectal examination and radiologic imaging) and biochemically (prostate-specific antigen assay) at baseline, and every 3 months for 2 years after RT and every 6 months subsequently. RESULTS: RT, whether conventional or hypofractionated, resulted in an increase in all six symptom categories used to characterize GI toxicity and in four of five symptom categories used to document urinary morbidity 1 month after therapy completion. Sexual dysfunction (based on limited data), which existed in more than one-third of patients before RT, also increased to just more than one-half of patients 1 month after RT. The increase in urinary toxicity after RT was not sustained (diurnal urinary frequency had decreased significantly at 2 years). In contrast, all six symptom categories of GI toxicity remained increased 1 year after RT. Four of the six GI symptom categories (rectal pain, mucous discharge, urgency of defecation, and rectal bleeding) were still increased at 2 years compared with baseline. Except for a slightly greater percentage of patients experiencing mild rectal bleeding at 2 years among those who received hypofractionated RT, no differences were noted in toxicity between the conventional and hypofractionated RT schedule. The mean prostate-specific antigen level was 14.0 +/- 1.0 ng/mL at baseline and declined to a nadir of 1.3 +/- 0.2 ng/mL at a median of 16.8 months (range 0.8-28.3) after RT completion. However, it then rose in 17 patients (8 in the hypofractionated and 9 in the conventional treatment group). Only 8 of these 17 patients were found to have signs of clinical relapse (5 local, 1 regional lymph node, and 2 systemic [bony metastases]) after histopathologic and radiologic reassessment). The remaining 9 patients had biochemical relapse only (defined as three consecutive rises in prostate-specific antigen after nadir). The 4-year biochemical relapse-free survival rate was 85.8% for all patients and did not differ significantly between the two radiation dose schedules (86.2% for the hypofractionated and 85.5% for the conventional fractionation group). CONCLUSION: RT for prostate carcinoma, using a three- or four-field 6-23-MV photon technique without posterior shielding of the lateral fields, is an underestimated cause of persistent GI morbidity. The incidence of clinically significant GI and urogenital toxicity after conventional and hypofractionated RT appears to be similar. Hypofractionated RT for carcinoma of the prostate seems just as effective as conventional RT after a median follow-up approaching 4 years.