Dose-volume analysis of predictors for acute anal toxicity after radiotherapy in prostate cancer patients

Xingsi Peng,Mengzhong Liu,Liru He,Maosheng Lin,Sijuan Huang,Chaonan Qian,Shiliang Liu,Sha Zhou,Jibin Li,Chengguang Lin,Shaomin Huang,Xiaobo Jiang

doi:10.1186/s13014-019-1374-1

Abstract

BackgroundThis study aimed to evaluate the clinical and dosimetric factors predictive of acute anal toxicity (AAT) after radiotherapy in prostate cancer (PCa) patients with or without hemorrhoids.MethodsWe analyzed data from 347 PCa patients (248 cases treated from July 2013 to November 2017 for training cohort and 99 cases treated in 2018 for validation cohort) treated with pelvic radiotherapy at a single institution. Anal canal dose–volume histogram was used to determine the prescribed dose. Univariate and multivariate analyses were used to evaluate the risk of AAT as a function of clinical and dosimetric factors.ResultsTotally, 39.5% (98/248) and 31.3% (31/99) of the PCa patients developed AAT in training and validation cohorts, respectively. The incidence of AAT was much higher in patients with hemorrhoids than in those without hemorrhoids in both training and validation cohorts. Hemorrhoids and volume received more than 20 Gy (V20) were valuated as independent factors for predicting AAT in training cohort. Similar results were also observed in our validation cohort. The combination of hemorrhoids and high anal canal V20 (> 74.93% as determined by ROC curves) showed the highest specificity and positive predictive values for predicting AAT in both training and validation cohorts.ConclusionsAAT occurs commonly in PCa patients with hemorrhoids during and after pelvic radiotherapy. Hemorrhoids and anal canal V20 are independent predictors of AAT. These factors should be carefully considered during treatment planning to minimize the incidence of AAT.

Highlights

Prostate cancer (PCa) is the most frequently diagnosed cancer among men in America and Europe, and its incidence is rapidly increasing in Asian counties, including China [1,2,3,4]
The incidence of anal toxicity (AAT) was much higher in patients with hemorrhoids than in those without hemorrhoids in training cohort (60.4% vs. 12.8%, P < 0.001) and validation cohort (44.2% vs. 17.0%, P = 0.004)
Portal imaging was performed before the initiation of the intensity-modulated radiotherapy (IMRT)/volumetric-modulated arc therapy (VMAT) course, while cone beam CT was performed before each treatment for patients treated with image-guided radiotherapy (IGRT)

Summary

Introduction

Prostate cancer (PCa) is the most frequently diagnosed cancer among men in America and Europe, and its incidence is rapidly increasing in Asian counties, including China [1,2,3,4]. Symptoms of acute anal toxicity (AAT), especially anal pain or bleeding, tend to be ignored because of their relatively lower severities. Anal pain and bleeding are quite common symptoms during pelvic radiotherapy for Asian patients. Two studies from Korea indicated that hemorrhoids are an important risk factor for AAT in patients undergoing pelvic radiotherapy [11, 12]. Both studies only enrolled small numbers of patients (31 and 33 patients, respectively) and included cases with different cancers and different radiation. This study aimed to evaluate the clinical and dosimetric factors predictive of acute anal toxicity (AAT) after radiotherapy in prostate cancer (PCa) patients with or without hemorrhoids

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