Role of early proctoscopy in predicting late symptomatic proctitis after external radiation therapy for prostate carcinoma

Purpose: To determine whether acute radiation-proctitis, diagnosed by proctoscopy after radiationtherapy for prostate cancer, can predict late clinical proctitis.Methods and Materials: A prospective study of 130 patients who underwent external radiationtherapy (RT) for stage T1 to T4 prostate cancer between 1997 and 2008 was performed. Treatmentswere conventional (2-dimensional [2D]) in 61 patients and 3D conformal in 69, witha median target dose of 72 Gy (70-74 Gy). Within 1 week after RT, proctoscopy was performedto detect possible acute endoscopic proctitis (AEP). Acute clinical proctitis (ACP) and late clinicalproctitis (LCP) were also evaluated. The median follow-up was 84 months (20-180 months).The influence of AEP and ACP on LCP occurrence was studied using the Cox model controllingfor age, dose, prostatectomy, RT technique (2D vs 3D), and hormone therapy.Results: AEP was detected in 15 patients (11.5%) and ACP in 67 (51.5%); in 13 cases (10%)AEP and ACP occurred simultaneously. Thirty-five cases of LCP were recorded. The 5-yearprobability of developing LCP was highest in patients with AEP and ACP (77%, 95% confidenceinterval [CI] 53%-94%) and lowest in asymptomatic patients (14%, 95% CI 7%-26%;P<.001). Compared to asymptomatic patients, the 5-year probability also was slightly increasedin patients with ACP only (26%, 95% CI 16%-40%; PZ.052). In multivariable analysis, thecombination of AEP and ACP was the main predictor of LCP: compared to asymptomaticpatients, the hazard ratio was 5.6 (2.1-15.2) in patients with AEP plus ACP (PZ.001) and2.1 (0.9-4.9) in those with ACP only (PZ.103).Conclusions: In patients with AEP and ACP, the risk of LCP was more than 5-fold increasedcompared to those who were asymptomatic, while a much smaller increase in risk occurredin patients with ACP only. Early proctoscopy can provide valuable information regarding thelikelihood of late proctitis