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

Abstract

Background 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. Methods We 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. Results Totally, 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. Conclusions AAT 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.

Aggravation of Hemorrhoids in Patients With Cervical Cancer Undergoing Radiotherapy: A Nationwide Population-based Study

“…The symptoms of acute proctitis are diarrhea and tenesmus and those of chronic proctitis are bleeding and painful defecation (10). However, if hemorrhoids are exacerbated, bleeding and pain appear early in the RT period (5,6). Therefore, the differential diagnosis of hemorrhoid aggravation and radiation-induced proctitis is essential to ensure that proper treatment choices are made, and it should be determined whether acute anal symptoms are due to hemorrhoid aggravation or lower rectal wall problems.…”

“…Radiation proctitis is a typical side-effect associated with pelvic RT (3,4). In particular, in patients with hemorrhoids, RT may aggravate anal symptoms such as pain or bleeding (5,6). In general, radiation proctitis tolerance is around 50 Gy (7).…”

“…The anal canal is known to tolerate prescribed whole-pelvic RT doses of 45-50 Gy (7). However, in patients with hemorrhoids, since the outer wall of the anal canal is weak, there is a possibility that hemorrhoids may worsen at lower doses (5,6). Furthermore, only a small number of studies have examined the relationship between hemorrhoid aggravation and RT dose (5,8,9).…”

Radiotherapy-Induced Digestive Injury: Diagnosis, Treatment and Mechanisms

“…On the basis of the dosevolume effect, radiotherapy-induced injury can be assessed by radiation dose and/or volume calculations. In this way, rectal toxicity (30,31), acute gastrointestinal toxicity (32,33), anal toxicity, and salivary gland injury were reported (34)(35)(36)(37)(38)(39)(40)(41)(42)(43) and precisely predicted (44). Conversely, Kim et al found that a higher dose was not associated with cervical esophageal cancer radiotherapy-induced stenosis (45).…”

Guidelines for radiotherapy of prostate cancer (2020 edition)

“…Currently, radiotherapy and ADT are combined by starting radiotherapy 2–3 months after ADT (it can be extended appropriately for patients with large prostate volume) to reduce the prostate volume, stabilize its size, and reduce radiation damage to the surrounding organs 39,40 …”