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Abstract: Despite anatomical proximity, prostatic adenocarcinoma with rectal invasion is rare. We describe a case of prostate cancer invading the anal sphincter, treated with radiation therapy (RT). A 78-year-old patient underwent definitive radiotherapy in 2018 because of poorly differentiated adenocarcinoma, Gleason 4 + 3 (7). The initial stage was mrT4N0 on magnetic resonance imaging (MRI) images. The pre-treatment prostate-specific antigen level was 142 ng/mL, and the patient was subjected to androgen deprivation therapy. RT was performed using volumetric modulated arc therapy (VMAT) and a dose of 76 Gy in 38 fractions. After 2 months, MRI showed a complete response. During RT, toxicity was limited to mild gastro-intestinal and urologic symptoms. This report is the first to describe prostate cancer invasion of the anal sphincter and to extend to that condition the use of RT - already regarded as a useful treatment option for inoperable locally advanced high-risk prostate cancer (PC). This study suggests that VMAT can be a safe and effective treatment option for locally advanced high-risk PC patients., (Copyright © 2023 Copyright: © 2023 Journal of Cancer Research and Therapeutics.)

The aim of this article is to review unrecognized toxicities resulting from radiation therapy of digestive neoplasms. Due to their precocious occurrence, acute toxicities are well-known by radiation oncologist, and their treatment well-established. Thus, acute toxicities will not be described in this review. We will focus on incidence, diagnosis, and management of late and uncommon toxicities occurring in the digestive tract and digestive organs. Prevention, by respecting healthy tissues constraints, is the main tool to reduce incidence of those rare complications. Nonetheless, once installed, late toxicities remain a major burden in terms of quality of life and can even be life threatening. Hence, information and education about their diagnosis and management is important., (Copyright © 2021 Société française de radiothérapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.)

Purpose: Changes in fraction size of external beam radiation therapy exert nonlinear effects on subsequent toxicity. Commonly described by the linear-quadratic model, fraction size sensitivity of normal tissues is expressed by the α/β ratio. We sought to study individual α/β ratios for different late rectal effects after prostate external beam radiation therapy., Methods and Materials: The CHHiP trial (ISRCTN97182923) randomized men with nonmetastatic prostate cancer 1:1:1 to 74 Gy/37 fractions (Fr), 60 Gy/20 Fr, or 57 Gy/19 Fr. Patients in the study had full dosimetric data and zero baseline toxicity. Toxicity scales were amalgamated to 6 bowel endpoints: bleeding, diarrhea, pain, proctitis, sphincter control, and stricture. Lyman-Kutcher-Burman models with or without equivalent dose in 2 Gy/Fr correction were log-likelihood fitted by endpoint, estimating α/β ratios. The α/β ratio estimate sensitivity was assessed using sequential inclusion of dose modifying factors (DMFs): age, diabetes, hypertension, inflammatory bowel or diverticular disease (IBD/diverticular), and hemorrhoids. 95% confidence intervals (CIs) were bootstrapped. Likelihood ratio testing of 632 estimator log-likelihoods compared the models., Results: Late rectal α/β ratio estimates (without DMF) ranged from bleeding (G1 + α/β = 1.6 Gy; 95% CI, 0.9-2.5 Gy) to sphincter control (G1 + α/β = 3.1 Gy; 95% CI, 1.4-9.1 Gy). Bowel pain modelled poorly (α/β, 3.6 Gy; 95% CI, 0.0-840 Gy). Inclusion of IBD/diverticular disease as a DMF significantly improved fits for stool frequency G2+ (P = .00041) and proctitis G1+ (P = .00046). However, the α/β ratios were similar in these no-DMF versus DMF models for both stool frequency G2+ (α/β 2.7 Gy vs 2.5 Gy) and proctitis G1+ (α/β 2.7 Gy vs 2.6 Gy). Frequency-weighted averaging of endpoint α/β ratios produced: G1 + α/β ratio = 2.4 Gy; G2 + α/β ratio = 2.3 Gy., Conclusions: We estimated α/β ratios for several common late adverse effects of rectal radiation therapy. When comparing dose-fractionation schedules, we suggest using late a rectal α/β ratio ≤ 3 Gy., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Watchful waiting in patients with rectal cancer with complete clinical response after chemoradiation therapy has gained increased popularity to avoid morbidity and mortality associated with surgery. Irradiation of the pelvis causes bowel dysfunction, but the effect on anorectal sensory function remains obscure in this patient category., Objective: The aim of this study was to characterize the sensory pathways of the gut-brain axis in patients with rectal cancer treated solely with chemoradiation therapy (nonconventional regime/dose) compared with healthy volunteers., Design: This is an explorative study., Settings: Sensory evaluation by rectal distension was performed and cortical evoked potentials were recorded during rapid balloon distensions of the rectum and anal canal. Latencies and amplitudes of cortical evoked potentials were compared, and the relative amplitude of 5 spectral bands from recorded cortical evoked potentials was used as an additional proxy of neuronal processing., Patients: Patients with rectal cancer solely with chemoradiation therapy (n = 13) a median of 3.2 years ago (range, 2.3-5.6 y) and healthy volunteers (n = 13) were included., Main Outcome Measures: Cortical evoked potentials were measured., Results: Patients had 35% lower rectal capacity at a maximum tolerable volume (p = 0.007). We found no differences in rectal cortical evoked potential latencies (p = 0.09) and amplitudes (p = 0.38) between groups. However, spectral analysis of rectal cortical evoked potentials showed a decrease in θ (4-8 Hz) and an increase in β (12-32 Hz) band activity in patients (all p < 0.001). Anal cortical potentials showed an increase in α (8-12 Hz) and β and a decrease in γ (32-70 Hz) band activity (all p < 0.001) in patients compared with healthy volunteers., Limitations: This is an explorative study of limited size., Conclusions: Chemoradiation therapy for distal rectal cancer causes abnormal cortical processing of both anal and rectal sensory input. Such central changes may play a role in symptomatic patients, especially when refractory to local treatments. See Video Abstract at http://links.lww.com/DCR/B270. RESPUESTA NEURONAL ANORMAL A ESTÍMULOS RECTALES Y ANALES, EN PACIENTES TRATADOS POR CÁNCER RECTAL DISTAL, CON QUIMIORRADIOTERAPIA DE DOSIS ALTA, SEGUIDA DE ESPERA VIGILANTE: La espera vigilante en pacientes de cáncer rectal, con respuesta clínica completa después de la quimiorradiación, ha ganado una mayor popularidad en evitar la morbilidad y mortalidad asociadas con la cirugía. La irradiación de la pelvis causa disfunción intestinal, pero el efecto sobre la función sensorial ano-rectal sigue siendo no claro, en esta categoría de pacientes.El objetivo de este estudio, fue caracterizar las vías sensoriales del eje intestino-cerebro en pacientes con cáncer rectal, tratados únicamente con quimiorradiación (régimen / dosis no convencional), en comparación con voluntarios sanos.Es un estudio exploratorio.Se realizó una evaluación sensorial por distensión rectal y se registraron los potenciales evocados corticales, durante las distensiones rápidas con balón en recto y canal anal. Se compararon las latencias y amplitudes de los potenciales evocados corticales, y la amplitud relativa de cinco bandas espectrales registradas, de potenciales evocados corticales, se usaron como proxy adicional del procesamiento neuronal.Pacientes de cáncer rectal, únicamente con terapia de quimiorradiación (n = 13) mediana de 3.2 años (rango 2.3-5.6) y voluntarios sanos (n = 13).Potenciales evocados corticales.Pacientes tuvieron una capacidad rectal menor del 35%, al volumen máximo tolerable (p = 0.007). No encontramos diferencias en las latencias potenciales evocadas corticales rectales (p = 0.09) y amplitudes (p = 0.38) entre los grupos. Sin embargo, el análisis espectral de los potenciales evocados corticales rectales, mostró una disminución en theta (4-8 Hz) aumento en beta (12-32 Hz), y actividad en banda en pacientes (todos p <0.001). Los potenciales evocados corticales anales mostraron un aumento en alfa (8-12 Hz) y beta, disminución en gamma (32-70 Hz), y actividad en banda (todos p <0.001), en pacientes comparados a voluntarios sanos.Este es un estudio exploratorio de tamaño limitado.La quimiorradiación para el cáncer rectal distal, ocasiona procesos corticales sensoriales anormales anales y rectales. Tales cambios centrales pueden desempeñar un papel en pacientes sintomáticos, especialmente cuando son refractarios a tratamientos locales. Consulte Video Resumen en http://links.lww.com/DCR/B270.

Purpose: The aim of this work was to determine how the spatial pattern of dose in the ano-rectal wall is related to late gastro-intestinal toxicity for prostate cancer patients treated with mainly IMRT. Patients and methods: Patients from the DUE-01 multicentre study with patient-reported (prospective) follow-up and available dosimetric data were included. Conventionally fractionated patients received 74-80 Gy and hypofractionated patients received 65-75.2 Gy. A large majority of the patients were treated with intensity-modulated radiotherapy (IMRT). Dose-surface maps (DSMs) for the anal canal and rectum as a single structure, and for the anal canal and the rectum separately, were co-registered rigidly in two dimensions and, for the patients with and without toxicity, respectively, the mean value of the dose in each pixel was calculated. A pixel-wise t -test was used to highlight the anatomical areas where there was a significant difference between the 'mean dose maps' of each group. Univariate models were also fitted to a range of spatial parameters. The endpoints considered were a mean grade ≥1 late fecal incontinence and a maximum grade ≥2 late rectal bleeding. Results: Twenty-six out of 213 patients had fecal incontinence, while 21/225 patients had rectal bleeding. Incontinence was associated with a higher dose in the caudal region of the anal canal; the most relevant spatial parameter was the lateral extent of the low and medium isodoses (5-49 Gy in EQD2). Bleeding was associated with high isodoses reaching the posterior rectal wall. The spatial dose parameters with the highest AUC value (.69) were the lateral extent of the 60-70 Gy isodoses. Conclusions: To avoid fecal incontinence it is important to limit the portion of the anal canal irradiated. Our analysis confirms that rectal bleeding is a function of similar spatial dose parameters for patients treated with IMRT, compared to previous studies on patients treated with three-dimensional conformal radiotherapy.

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.

Background and Purpose: To assess the long-term anorectal function in rectal cancer patients following a watch-and-wait policy after chemoradiotherapy and to investigate the dose-volume effects of radiotherapy on the anorectal function., Methods and Materials: Thirty-three patients with primary rectal cancer who were treated with chemoradiotherapy and a watch-and-wait policy with minimum follow-up of 2  years were included. We assessed the anorectal function using anorectal manometry and patient reported outcomes (Vaizey and LARS score). Dose-volume histograms were calculated for the rectum and anal sphincter complex, and associations between the dose-volume parameters and anorectal function were assessed., Results: D mean to the rectum and anal sphincter complex was 50.5 Gy and 44.7 Gy, respectively. After a median follow-up of 38 (range 23-116) months, 33.3% of the patients reported major LARS. Mean LARS score was 23.4 ± 11.3 and mean Vaizey score was 4.3 ± 4.1. The most frequent complaints were clustering of defaecation and faecal urgency. Trends towards a higher Vaizey and LARS score after higher anal sphincter complex dose were observed, although these associations were not statistically significant., Conclusions: This is the first study to investigate the late dose-volume effects of radiotherapy specifically on the anorectal function in rectal cancer patients. One-third of the patients had major LARS and the most frequent reported complaints were clustering and faecal urgency. Additionally, we observed trends towards worse long-term anorectal function after higher anal sphincter complex radiotherapy dose. However, this should be evaluated on a larger scale. Future efforts to minimise the dose to the sphincters could possibly reduce the impact of radiotherapy on the anorectal function., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Neoadjuvant radio- or chemoradiation (nIRT) therapy is the standard treatment for loco-regional advanced rectal cancer patients of the lower or middle third. Currently, intensity modulated radiation therapy (IMRT) is not the recommended radiation technique even though IMRT has advantages compared to 3D-radiation regarding dose sparing to organs at risk like small bowel and urinary bladder. So far, the benefit of IMRT concerning the anal sphincter complex is not examined. With this study we intended to evaluate the dose distribution on the anal sphincters of rectal cancer patients treated with IMRT in comparison with 3D-techniques., Methods: We selected 16 patients for the IMRT-group and 16 patients for the 3D-group with rectal cancer of the middle third who were treated in our institute. All patients received 45 Gy in a chemoradiation protocol. Patients in both groups were matched regarding stage, primary tumor distance to the anal verge and size of the tumor. We delineated the internal and external anal sphincters, the addition of both sphincters and the levator ani muscle in all patients. Subsequently, we evaluated and compared dose parameters of the different sphincters in both groups and analysed the configuration of the isodoses in the area of the caudal radiation field, respectively., Results: Most of the relevant dose parameters of the caudal sphincters (Dmean, Dmedian, V10-V40) were significantly reduced in the IMRT-group compared to the 3D-group. Accordingly, the isodoses at the caudal edge of the target volume in the IMRT group demonstrated a steep dose fall. The levator ani muscle always was included into the planned target volumes and received the full dose in both groups., Conclusions: The modern VMAT-IMRT can significantly reduce the dose to the anal sphincters for rectal cancer patients of the middle third who were treated with conventional chemoradiation therapy.

Introduction: There is a paucity of data on incidence and mechanisms of long-term gastrointestinal consequences after chemoradiotherapy for anal cancer. Most of the adverse effects reported were based on traditional external beam radiotherapy whilst only short-term follow-ups have been available for intensity-modulated radiotherapy, and there is lack of knowledge about consequences of dose-escalation radiotherapy., Method: A systematic literature review., Results: Two thousand nine hundred and eighty-five titles (excluding duplicates) were identified through the search; 130 articles were included in this review. The overall incidence of late gastrointestinal toxicity was reported to be 7-64.5%, with Grade 3 and above (classified as severe) up to 33.3%. The most commonly reported late toxicities were fecal incontinence (up to 44%), diarrhea (up to 26.7%), and ulceration (up to 22.6%). Diarrhea, fecal incontinence and buttock pain were associated with lower scores in radiotherapy specific quality of life scales (QLQ-CR29, QLQ-C30, and QLQ-CR38) compared to healthy controls. Intensity-modulated radiation therapy appears to reduce late toxicity., Conclusion: Late gastrointestinal toxicities are common with severe toxicity seen in one-third of the patients. These symptoms significantly impact on patients' quality of life. Prospective studies with control groups are needed to elucidate long-term toxicity.

Introduction: Skin bolus may routinely be used in the perineum to build up the surface dose in the treatment of anal cancer (ACC); this may contribute to significant acute skin toxicity. Skin bolus may not be needed with the introduction of modern radiotherapy techniques if these planning techniques would achieve adequate surface dose. Our study is to ascertain if appropriate skin dose can be achieved without the use of bolus when VMAT is used in the treatment of ACC., Methods: The study includes 10 ACC patients treated with VMAT radiotherapy. Optically stimulated luminescence dosimeters (OSLD) are used to evaluate whether the calculated dose for the VMAT planning technique (VMAT-PT) accurately predicted the dose delivered to peri-anal target region without bolus. The OSLD recorded the dose at the anal verge or at the lower most extent of the tumour for each patient over two fractions. The OSLD was read after each of the two fractions, and the average value was reported. The mean dose over a volume centred on the anal marker was calculated in the treatment planning system (TPS)., Results: The mean TPS-calculated dose was 186.1 cGy. The mean of the OSLD-measured doses was 205.7 cGy for a single fraction. The mean of the measured doses was 10.6% higher than the mean of the calculated doses., Conclusions: The calculated dose for the VMAT-PT consistently under-predicted the dose delivered to the peri-anal target region without bolus. Routine use of skin bolus could be avoided with VMAT-PT when the patient is treated in a supine position., (© 2018 The Royal Australian and New Zealand College of Radiologists.)

Background and Purpose: Late anorectal toxicity influences quality of life after external beam radiotherapy (EBRT) for prostate cancer. A daily inserted endorectal balloon (ERB) during EBRT aims to reduce anorectal toxicity. Our goal is to objectify anorectal function over time after prostate intensity-modulated radiotherapy (IMRT) with ERB., Material and Methods: Sixty men, irradiated with IMRT and an ERB, underwent barostat measurements and anorectal manometry prior to EBRT and 6 months, one year and 2 years after radiotherapy. Primary outcome measures were rectal distensibility and rectal sensibility in response to stepwise isobaric distensions and anal pressures., Results: Forty-eight men completed all measurements. EBRT reduced maximal rectal capacity 2 years after EBRT (250 ± 10 mL vs. 211 ± 10 mL; p < 0.001), area under the pressure-volume curve (2878 ± 270 mL mmHg vs. 2521 ± 305 mL mmHg; p = 0.043) and rectal compliance (NS). Sensory pressure thresholds for first sense and first urge (both p < 0.01) increased. Anal maximum pressure diminished after IMRT (p = 0.006)., Conclusions: Rectal capacity and sensory function are increasingly affected over time after radiotherapy. There is an indication that these reductions are affected less with IMRT + ERB compared to conventional radiation techniques., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background and Purpose: Chemoradiotherapy (CRT) is the standard therapy for localized anal cancer (AC), but this treatment is associated with substantial toxicity. However, there is a lack of prospectively collected toxicity and patient reported outcome (PRO) data from larger cohorts. The purpose was to prospectively collect and determine agreement between physician assessed toxicity (CTCAE) and PRO during and after CRT and to compare IMRT, VMAT and proton-based planning in a subgroup of patients., Material and Methods: Patients, treated with CRT for AC, were included between 2015 and 2017. NCI-CTCAE v.4.0, EORTC QLQ-C30 and CR29 data were collected baseline, mid-therapy, end-of therapy and 2-4 weeks posttherapy. Treatment planning with 5- or 6-fixed field IMRT, 2 and 3 arc VMAT, and 3- and 4-field proton plans were compared., Results: One-hundred patients were included. Both CTCAE and PROs related to acute toxicity reached a maximum at end of therapy. Incidences of PROs were markedly higher with only slight to fair agreement to CTCAE, (κ 13-37). Comparative planning revealed dosimetric equality of IMRT and VMAT plans, but superiority of proton plans., Conclusions: The high incidence of PRO scores and weak agreement to CTCAE suggest that PROs are important tools complementary to CTCAE in evaluating patient symptoms during and after CRT. Proton therapy has the potential to lower radiation doses to most organs at risk., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: Sphincter-sparing radiotherapy or chemoradiation (RT/CRT) have become the standard treatments for most patients with anal cancer. Unfortunately, long-term survivors often suffer from severe bowel symptoms indicating sensory dysfunction. The aim of the present study was to characterize the sensory pathways of the brain-gut axis after radiotherapy for anal cancer., Method: Cortical evoked potentials (CEPs) were recorded during repeated, rapid balloon distensions of the rectum and anal canal in 13 patients with anal cancer treated with radiotherapy or chemoradiation and in 17 healthy volunteers. Latencies and amplitudes of rectal CEPs were compared between the groups. CEPs from both rectal and anal distensions were examined using single sweep spectral band analysis to determine the relative amplitude of five spectral bands as a proxy of neuronal processing., Results: Groups were comparable by age (62.4 ± 7.8 vs 58.9 ± 8.9, p < 0.32) and gender. Patients had a mean Wexner fecal incontinence score of 5.5 (±3.8) and median LARS Score of 29 (0-39). Rectal CEP latencies were prolonged in patients (F = 11.7; p < 0.001), whereas amplitudes were similar (F = 0.003; p = 0.96). Spectral analysis of CEPs from rectal distensions showed significant differences between groups in theta (4-8 Hz), alpha (8-12 Hz), beta (12-32 Hz) and gamma (32-70 Hz) bands (all p < 0.001) and CEPs from anal distensions showed significant differences in the alpha, beta and gamma bands (all p ≤ 0.002)., Conclusion: Patients treated with RT/CRT for anal cancer have impaired ano-rectal sensory pathways and abnormal cortical processing. This may play a central role for the pathogenesis of late proctopathy., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Objective: Literature regarding image-guidance and interfractional motion of the anal canal (AC) during anal cancer radiotherapy is sparse. This study investigates interfractional AC motion during anal cancer radiotherapy., Methods: Bone matched cone beam CT (CBCT) images were acquired for 20 patients receiving anal cancer radiotherapy allowing population systematic and random error calculations. 12 were selected to investigate interfractional AC motion. Primary anal gross tumour volume and clinical target volume (CTVa) were contoured on each CBCT. CBCT CTVa volumes were compared to planning CTVa. CBCT CTVa volumes were combined into a CBCT-CTVa envelope for each patient. Maximum distortion between each orthogonal border of the planning CTVa and CBCT-CTVa envelope was measured. Frequency, volume and location of CBCT-CTVa envelope beyond the planning target volume (PTVa) was analysed., Results: Population systematic and random errors were 1 and 3 mm respectively. 112 CBCTs were analysed in the interfractional motion study. CTVa varied between each imaging session particularly T location patients of anorectal origin. CTVa border expansions ≥ 1 cm were seen inferiorly, anteriorly, posteriorly and left direction. The CBCT-CTVa envelope fell beyond the PTVa ≥ 50% imaging sessions (n = 5). Of these CBCT CTVa distortions beyond PTVa, 44% and 32% were in the upper and lower thirds of PTVa respectively., Conclusion: The AC is susceptible to volume changes and shape deformations. Care must be taken when calculating or considering reducing the PTV margin to the anus. Advances in knowledge: Within a limited field of research, this study provides further knowledge of how the AC deforms during anal cancer radiotherapy.

Purpose: To compare GI symptoms, measures of generic and disease specific health related quality of life (HRQoL), anorectal and pudendal nerve function and anal sphincter morphology between (i) patients ≥2 years after 3D conformal radiotherapy (3D-CRT)±high dose rate (HDR) brachytherapy for carcinoma of the prostate and aged matched patients before radiotherapy and (ii) symptomatic and asymptomatic patients ≥2 years after 3D-CRT ± HDR brachytherapy., Material and Methods: Methodology included: (i) modified LENT-SOMA scales for GI symptoms, (ii) EORTC QLQ-C30 and EORTC QLQ-PR25 questionnaires for generic and disease specific HRQoL, (iii) anorectal manometry and terminal motor latency for anorectal and pudendal nerve function and (iv) endorectal ultrasound for anal sphincter morphology. GI symptoms, parameters of HRQoL, anorectal and pudendal nerve function and anal sphincter morphology were compared using Mann-Whitney's U, unpaired t and χ 2 tests., Results: Impairment of HRQoL bowel symptoms in the patients ≥2 years after 3D-CRT ± HDR brachytherapy was associated with worse anorectal motor and sensory function, internal and external anal sphincter morphology and 5× greater prevalence of pudendal nerve dysfunction compared with age matched patients before radiotherapy. Symptomatic patients had worse (i) HRQoL measures including global quality of life and bowel and urinary symptom scores, (ii) rectal bleeding, fecal urgency and incontinence scores and (iii) a 2× higher prevalence of pudendal nerve dysfunction compared with asymptomatic patients. Rectal and anal (i) V 40 Gy >65%, (ii) Dmax >60 Gy, (iii) pudendal nerve Dmax >60 Gy and (iv) Anal V 60 Gy >40% were associated with a greater prevalence of pudendal nerve dysfunction., Conclusions: 3D-CRT ± HDR brachytherapy for prostate carcinoma, impairs late functional measures including HRQoL, anorectal and pudendal nerve function. Rectal, anal and pudendal nerve radiation dose constraints are proposed for reducing the prevalence of pudendal nerve dysfunction.

Background: Sphincter-sparing radiotherapy or chemoradiation are standard treatments for patients with anal cancer. The ultimate treatment goal is full recovery from anal cancer with preserved anorectal function. Unfortunately, long-term survivors often suffer from severe anorectal symptoms. The aim of the present study was to characterize changes in anorectal physiology after radiotherapy for anal cancer., Method: We included 13 patients (10 women, age 63.4 ± 1.9) treated with radiotherapy or chemoradiation for anal cancer and 14 healthy volunteers (9 women, age 61.4 ± 1.5). Symptoms were assessed with scores for fecal incontinence and low anterior resection syndrome. Anorectal physiology was examined with anorectal manometry and the Functional Lumen Imaging Probe., Results: Patients had a median Wexner fecal incontinence score of 5 (0-13) and a median LARS score of 29 (0-39). Compared to healthy volunteers, patients had lower mean (±SE) anal -resting (38 ± 5 vs. 71 ± 6, p < .001) and -squeeze pressures (76 ± 11 vs. 165 ± 15, p < .001). Patients also had lower anal yield pressure (15.5 ± 1.3 mmHg vs. 28.0 ± 2.0 mmHg, p < .001), higher distensibility, and lower resistance to flow (reduced resistance ratio of the anal canal during distension, q = 5.09, p < .001). No differences were found in median (range) rectal volumes at first sensation (70.5 (15-131) vs. 57 (18-132) ml, p > .4), urge (103 (54-176) vs. 90 (32-212), p > .6) or maximum tolerable volume (173 (86-413) vs. 119.5 (54-269) ml, p > .10)., Conclusion: Patients treated with radiotherapy or chemoradiation for anal cancer have low anal resting and squeeze pressures as well as reduced resistance to distension and flow.

Fecal incontinence (FI) is a disabling problem affecting women. Conservative treatment includes dietary modification, antimotility agents, and pelvic floor physical therapy. If conservative medical management is unsuccessful, surgical intervention may be required. Surgical options include rectal sphincteroplasty, bulking agent injection, radiofrequency anal sphincter remodeling, and sacral nerve stimulation therapy. Recently, a new therapy for FI, the FENIX Continence Restoration System (Torax Medical, Inc., Shoreview, MN), has become available. The FENIX device is placed through a perineal incision; however, pelvic radiation and previous anal carcinoma are both contraindications. We report the case of a 62-year-old woman with FI after anal carcinoma. Treatment included surgery, chemotherapy, and pelvic radiation. Initially, she was treated with conservative therapy and sacral nerve stimulation, which were only partially effective. A physical examination showed perineal skin changes consistent with previous radiation, which increased the patient's risk of infection and a nonhealing wound. Therefore, a robotic approach was used to place the FENIX device and improve the patient's quality of life. Our case sets a precedent for expanding the treatment options of FI in patients with previous pelvic radiation and using a robotic approach for the placement of the FENIX device., (Copyright © 2017 American Association of Gynecologic Laparoscopists. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the effect of a shrinking rectal balloon implant (RBI) on the anorectal dose and complication risk during the course of moderately hypofractionated prostate radiotherapy., Methods: In 15 patients with localized prostate cancer, an RBI was implanted. A weekly kilovolt cone-beam computed tomography (CBCT) scan was acquired to measure the dynamics of RBI volume and prostate-rectum separation. The absolute anorectal volume encompassed by the 2 Gy equieffective 75 Gy isodose (V 75Gy ) was recalculated as well as the mean anorectal dose. The increase in estimated risk of grade 2-3 late rectal bleeding (LRB) between the start and end of treatment was predicted using nomograms. The observed acute and late toxicities were evaluated., Results: A significant shrinkage of RBI volumes was observed, with an average volume of 70.4% of baseline at the end of the treatment. Although the prostate-rectum separation significantly decreased over time, it remained at least 1 cm. No significant increase in V 75Gy of the anorectum was observed, except in one patient whose RBI had completely deflated in the third week of treatment. No correlation between mean anorectal dose and balloon deflation was found. The increase in predicted LRB risk was not significant, except in the one patient whose RBI completely deflated. The observed toxicities confirmed these findings., Conclusions: Despite significant decrease in RBI volume the high-dose rectal volume and the predicted LRB risk were unaffected due to a persistent spacing between the prostate and the anterior rectal wall.

Purpose: The phase 3 HYpofractionated irradiation for PROstate cancer (HYPRO) trial randomized patients with intermediate- to high-risk localized prostate cancer to conventionally fractionated (78 Gy in 39 fractions) or hypofractionated (64.6 Gy in 19 fractions) radiation therapy. Differences in techniques and treatment protocols were present between participating centers. This study aimed to compare dose parameters and patient-reported gastrointestinal symptoms between these centers., Methods and Materials: From the trial population, we selected patients (N=572) from 4 treatment centers who received image guided (IG) intensity modulated radiation therapy (IMRT). Center A (n=242) applied planning target volume (PTV) margins of 5 to 6 mm and was considered the reference center. In center B (n=170, 7-mm margins), magnetic resonance imaging (MRI) was integrated in treatment planning. An endorectal balloon (ERB) was applied in center C (n=85, 7-mm margins). Center D (n=75) applied the largest PTV margins of 8 mm. The study protocol provided identical anorectal dose constraints, and local protocols were applied for further treatment optimization. Anorectal dose-surface histograms were compared by applying t tests. Rectal complaints during follow-up (6 months to 4 years) were compared in a generalized linear model, adjusting for age, follow-up, treatment arm, and hormone therapy., Results: Favorable anorectal dose distributions were found for center B (MRI delineation) and center C (ERB application) as compared with centers A and D. These were associated with significantly lower incidences of patient-reported complaints of rectal incontinence, use of incontinence pads, and rectal discomfort in these centers. Furthermore, lower incidences of increased stool frequency (≥4 per day) and mucous loss were observed for center C., Conclusions: Despite comparable IG-IMRT techniques and predefined dose constraints, pronounced differences in dose distributions and toxicity rates were observed. MRI delineation and ERB application were associated with favorable rectal dose parameters and toxicity profiles, whereas a 2- to 3-mm difference in PTV margins did not translate into observed differences. We conclude that choices for treatment optimization of IG-IMRT are important and clinically relevant for patients since these affect symptoms experienced in daily life., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: The objective of the study is to determine the correlations among the variables of dose and the sphincter function (SF) in patients with locally advanced rectal cancer treated with preoperative capecitabine/radiotherapy followed by low anterior resection (LAR) + TME., Methods: We retrospectively reviewed 92 consecutive patients with LARC treated at our center with LAR from 2006 and more than 2 years free from disease. We re-contoured the anal sphincters (AS) of patients with the help of the radiologist. SF was assessed with the Wexner scale (0-20 points, being punctuation inversely proportional to annal sphincter functionality). All questionnaires were filled out between January 2010 and December 2012. Dosimetric parameters that have been studied include V 20 , V 30 , V 40 , V 50 , mean dose (D mean ), minimum dose (D min ), D 90 (dose received by 90% of the sphincter) and D 98 ., Statistical Analysis: The correlations among the variables of dose and SF were studied by the Spearman correlation coefficient. Differences in SF relating to maximum doses to the sphincter were assessed by the Mann-Whitney test., Results: Mean Wexner score was 5.5 points higher in those patients with V 20  > 0 compared to those for which V 20  = 0 (p = 0.008). In a multivariate regression model, results suggest that the effect of V 20 on poor anal sphincter control is independent of the effect of distance, with an adjusted OR of 3.42., Conclusions: In order to improve the SF in rectal cancer treated with preoperative radiotherapy/capecitabine followed by conservative surgery, the maximum radiation dose to the AS should be limited, when possible, to <20 Gy.

The treatment of anal cancer has evolved remarkably in the past 30 years. Definitive chemoradiotherapy is the standard of care, allowing organ preservation and maintenance of continence for most patients. This article reviews recent advances in radiotherapy planning and delivery that have resulted in improvements in treatment-related toxicity. Most notably, the advent and wide adoption of intensity-modulated radiotherapy provides a superior toxicity profile compared with older techniques, while maintaining similar oncologic outcomes. Current areas of active research include optimizing and individualizing treatment intensity and possible integration of biologic agents and immunotherapies in the treatment of anal cancer., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To evaluate the impact of endorectal balloon (ERB) on anorectal dose during postoperative VMAT of prostate cancer., Methods: In ten patients referred for salvage radiotherapy CTs were obtained without ERB and with air-filled ERB of 50ml and 100ml. CTs were repeated weekly (4-6 control CTs) and registered to the respective planning CT. For each planning CT, a VMAT plan was made with defined anorectal dose constraints and propagated on the respective control CTs. The dose volumes V40Gy, V60Gy and V65Gy of the rectal and anal wall (Rwall and Awall, respectively) and the ERB position were obtained from each plan., Results: In plans with ERB, the mean Rwall dose volumes V40Gy, V60Gy and V65Gy were higher by 8%, 5% and 2% (ERB 50ml) and 2%, 3% and 3% (ERB 100ml) in comparison to plans without ERB. The respective Awall dose volume differences were 2%, 0%, -1% (ERB 50ml), and -3%, -2%, -2% (ERB 100ml). The dose volume variability of the Rwall was comparable with and without ERB, but was slightly reduced by ERB for the Awall. The mean ERB position variability was >2mm in anterior-posterior and inferior-superior directions., Conclusion: The use of ERB during post-operative VMAT has no advantages for anorectal dose., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Radical concurrent chemoradiotherapy with 5-fluorouracil and mitomycin C (MMC) remains the standard of care for squamous cell carcinoma of the anus. Phase III trials over 2 decades have used combined radiation doses of 50 to 60 Gy with concurrent fluoropyrimidines, MMC, or cisplatin in various doses and schedules. Modern radiotherapy techniques allow the production of highly conformal plans, decreasing radiation doses to the organs at risk and ensuring a shorter overall treatment time without the need for treatment breaks. These techniques offer the potential to improve compliance and even escalate doses of radiation., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background: To analyze the relationship between mean radiation dose to the bowels and the anal-sphincter and occurrence of 'defecation into clothing without forewarning', a specific and serious fecal incontinence symptom after gynecological radiotherapy. Additional potential risk factors associated with the symptom are explored., Material and Methods: Data were collected for 519 eligible gynecological cancer survivors, treated with pelvic radiotherapy, with a median follow-up of 5.8 years, using a study-specific questionnaire and medical records. Correlations between defecation into clothing without forewarning and mean dose to organs at risk; the anal-sphincter region, the rectum, the sigmoid and the small intestines were investigated, also taking other risk factors into account., Results: Twelve percent reported having had the symptom at least once in the preceding six months. Mean doses >50 Gy to the anal-sphincter region, the rectum, the sigmoid and the small intestines were related to the occurrence of the symptom. Significantly associated risk factors were deliveries with high birth weight, heart failure and lactose and/or gluten intolerance. After adjusting for these factors, mean doses >50 Gy to the anal-sphincter region, the sigmoid and the small intestines remained related to the occurrence of the symptom., Conclusion: Mean doses to the bowels and anal-sphincter region are related to the risk of defecation into clothing without forewarning in long-term gynecological cancer survivors treated with pelvic radiotherapy. Further radiobiological modeling may distinguish which organ(s) contribute most to development of the symptom.

Background: Neoadjuvant chemoradiotherapy (nCRT) in addition to the curative surgery has been the first of treatment for local advanced rectal cancer because of its benefits in local recurrence and sphincter-saving. However, its side effects on anorectal function have been recognized. The histopathological changes on internal anal sphincter (IAS) have been reported, but ultrastructure changes of external anal sphincter (EAS) are unknown. The aim of this study is to detect the alterations on the gross morphology of IAS and ultrastructure of EAS after nCRT., Methods: We collected 34 anal canal specimens of patients undergoing abdominoperineal resection (APR) prospectively. The length and thickness of IAS were measured with vernier caliper. The EAS was dissected for observation with transmission electron microscope (TEM)., Results: Ten patients received nCRT (nCRT group) before surgery and 24 underwent APR directly (control group). The length and thickness of IAS in nCRT group were 22.68 ± 3.56 and 5.39 ± 0.74 mm, respectively. These parameters were 21.28 ± 3.62 and 5.35 ± 1.12 mm in control group, respectively. There were no significant differences in the length and thickness of IAS between the two groups (P>0.05). In nCRT group, the sarcomere and myofibril were arranged disorderly and parts of them that were filled with collagenous fiber, triads, and mitochondria were destroyed severely and the glycogenosome also distributed disorderly. Such alterations of EAS did not occur in control group., Conclusions: The nCRT cannot change the gross morphology of IAS, while it induces serious damages to the ultrastructures of EAS which may adversely affect the anorectal function.

Background Chronic gastrointestinal (GI) morbidity occurs in ≥50% of patients after external beam radiotherapy (EBRT) for carcinoma of prostate (CaP). This prospective, longitudinal study examines which baseline measurements of: 1) homocysteine and micronutrients in plasma; 2) chromosome damage/misrepair biomarkers; and 3) anal and rectal dose volume metrics predict GI morbidity after EBRT. Patients and methods In total, 106 patients with CaP had evaluations of GI symptoms (modified LENT-SOMA questionnaires) before EBRT and at one month, one, two and three years after its completion. Other variables measured before EBRT were: 1) plasma concentrations of homocysteine and micronutrients including caroteinoids and selenium; 2) chromosome damage/DNA misrepair (micronuclei/nucleoplasmic bridge) indices; and 3) mean anal and rectal wall doses and volumes of anal and rectal walls receiving ≥40 Gy and ≥60 Gy. Univariate and multivariate analyzes examined the relationships among: 1) plasma levels of homocysteine and micronutrients; 2) indices of chromosome damage/DNA misrepair; and 3) mean anal and rectal wall doses and volumes of anal and rectal walls receiving ≥40 Gy and ≥60 Gy and total GI symptom scores from one month to three years after EBRT. Results Increased frequency and urgency of defecation, rectal mucous discharge and bleeding after EBRT resulted in sustained rises in total GI symptom scores above baseline at three years. On univariate analysis, total GI symptom scores were significantly associated with: 1) plasma selenium and α tocopherol; 2) micronuclei indices of DNA damage; 3) mean anal and rectal wall doses; and 4) volumes of anal and rectal wall receiving ≥40 Gy and ≥60 Gy (p = 0.08-<0.001). On multivariate analysis, only volume of anal wall receiving ≥40 Gy was significant for increased GI symptoms after EBRT (p < 0.001). Conclusion The volume of anal wall receiving ≥40 Gy predicts chronic GI morbidity after EBRT for CaP.

Purpose: The purpose of this study is to investigate the influence of radiotherapy (RT) on anorectal function and radiation-induced toxicity in patients with prostate cancer., Materials and Methods: Fifty-four patients who were treated with RT for prostate cancer (T1c-4N0-1M0) were evaluated. To assess the changes in anorectal function, two consecutive anorectal manometry readings were performed in patients, before and after 4-6 months of RT. Late gastrointestinal (GI) toxicity was defined as symptoms occurring more than 6 months after RT. The median radiation dose was 70.0 Gy (range, 66.0 to 74.0 Gy). Whole pelvis field RT was performed in 16 patients (29.6%). Grade of late radiation toxicity was defined in accordance to the severity of symptoms (Gulliford's scoring system)., Results: The median follow-up period was 60 months. Resting anal pressure (p=0.001), squeeze pressure (p < 0.001), and urge to defecate volume (p=0.025) were significantly reduced after RT. Fourteen patients (25.9%) experienced late GI toxicities. Among them, nine (16.7%) showed severe (grade ≥ 2) late toxicities. Elevated resting and squeeze external anal sphincter pressure prior to RT and large urge to defecate volumes after RT were associated with the occurrence of late GI toxicities., Conclusion: RT caused symptomatic anorectal dysfunction and resulted in a weakened anal sphincter. Increased urge to defecate volumes after RT were related to late GI toxicities. Elevated resting and squeeze anal sphincter pressure prior to RT rodcan be used to identify patients with an increased risk of late GI toxicities.

Background and Purpose: We evaluated dose distributions in the anorectum and its relation to acute gastrointestinal toxicities using dose surface maps in an image-guided (IG) IMRT and 3D-conformal radiotherapy (3D-CRT) population., Material and Methods: For patients treated to 78 Gy with IG-IMRT (n=260) or 3D-CRT (n=215), for whom acute toxicity data were available, three types of surface maps were calculated: (1) total anorectum using regular intervals along a central axis with perpendicular slices, (2) the rectum next to the prostate, and (3) the anal canal (horizontal slicing). For each toxicity, an average dose map was calculated for patients with and without the toxicity and subsequently dose difference maps were constructed, 3D-CRT and IG-IMRT separately. P-values were based on permutation tests., Results: Dose distributions in patients with grade ⩾2 acute proctitis were significantly different from dose distributions in patients without toxicity, for IG-IMRT and 3D-CRT. At the cranial and posterior rectal site, in areas receiving moderate dose levels (≈25-50 Gy), dose differences up to 10 Gy were identified for IG-IMRT. For pain, cramps, incontinence, diarrhea and mucus loss significant differences were found as well., Conclusions: We demonstrated significant relationships between acute rectal toxicity and local dose distributions. This may serve as a basis for subsequent dose-effect modeling in IG-IMRT, and improved dose constraints in current clinical practice., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Objective: Patients with asymptomatic haemorrhoids are known to be less tolerant of radiation doses lower than known tolerance doses. In the present study, the authors sought to identify the risk factors of acute haemorrhoid aggravation after whole pelvic radiotherapy (WPRT)., Methods: The records of 33 patients with cervical, rectal or prostate cancer with asymptomatic haemorrhoids, which were confirmed by colonoscopy before the start of radiotherapy (RT), were reviewed. Acute anal symptoms, such as anal pain and bleeding, were observed up to 1 month after RT completion. Dosimetric and patient factors were analysed, and subgroup analyses were performed., Results: The median induction dose for acute anal symptoms was 34.1 Gy (range, 28.8-50.4 Gy). Post-operative treatment intent showed more acute anal toxicity of patient factors (p = 0.04). In subgroup analysis, post-operative treatment intent and concurrent chemoradiotherapy were found to be related to acute anal symptoms (p < 0.01). Of the dosimetric factors, V10 tended to be related to acute anal symptoms (p = 0.08)., Conclusion: This study indicates that asymptomatic haemorrhoid may deteriorate after low-dose radiation and that patient factors, such as treatment intent and concurrent chemotherapy, probably influence anal toxicity. In patients with asymptomatic haemorrhoids, WPRT requires careful dosimetry and clinical attention., Advances in Knowledge: The tolerance of anal canal tends to be ignored in patients with pelvic cancer who are undergoing WPRT. However, patients with asymptomatic haemorrhoids may be troubled by low radiation doses, and further studies are required.

The standard treatment of locally advanced (stage II and III) squamous cell carcinoma of the anal canal consists of concurrent chemoradiotherapy (two cycles of 5-fluoro-uracil, mitomycin C, on a 28-day cycle), with a dose of 45 Gy in 1.8 Gy per fraction in the prophylactic planning target volume and additional 14 to 20 Gy in the boost planning target volume (5 days per week) with a possibility of 15 days gap period between the two sequences. While conformal irradiation may only yield suboptimal tumor coverage using complex photon/electron field junctions (especially on nodal areas), intensity modulated radiation therapy techniques (segmented static, dynamic, volumetric modulated arc therapy and helical tomotherapy) allow better tumour coverage while sparing organs at risk from intermediate/high doses (small intestine, perineum/genitalia, bladder, pelvic bone, etc.). Such dosimetric advantages result in fewer severe acute toxicities and better potential to avoid a prolonged treatment break that increases risk of local failure. These techniques also allow a reduction in late gastrointestinal and skin toxicities of grade 3 or above, as well as better functional conservation of anorectal sphincter. The technical achievements (simulation, contouring, prescription dose, treatment planning, control quality) of volumetric modulated arctherapy are discussed., (Copyright © 2015 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.)

Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows significant dose reductions to organs at risk in prostate cancer patients. However, clinical data identifying the benefits of IG-IMRT in daily practice are scarce. The purpose of this study was to compare dose distributions to organs at risk and acute gastrointestinal (GI) and genitourinary (GU) toxicity levels of patients treated to 78 Gy with either IG-IMRT or 3D-CRT., Methods and Materials: Patients treated with 3D-CRT (n=215) and IG-IMRT (n=260) receiving 78 Gy in 39 fractions within 2 randomized trials were selected. Dose surface histograms of anorectum, anal canal, and bladder were calculated. Identical toxicity questionnaires were distributed at baseline, prior to fraction 20 and 30 and at 90 days after treatment. Radiation Therapy Oncology Group (RTOG) grade ≥1, ≥2, and ≥3 endpoints were derived directly from questionnaires. Univariate and multivariate binary logistic regression analyses were applied., Results: The median volumes receiving 5 to 75 Gy were significantly lower (all P<.001) with IG-IMRT for anorectum, anal canal, and bladder. The mean dose to the anorectum was 34.4 Gy versus 47.3 Gy (P<.001), 23.6 Gy versus 44.6 Gy for the anal canal (P<.001), and 33.1 Gy versus 43.2 Gy for the bladder (P<.001). Significantly lower grade ≥2 toxicity was observed for proctitis, stool frequency ≥6/day, and urinary frequency ≥12/day. IG-IMRT resulted in significantly lower overall RTOG grade ≥2 GI toxicity (29% vs 49%, respectively, P=.002) and overall GU grade ≥2 toxicity (38% vs 48%, respectively, P=.009)., Conclusions: A clinically meaningful reduction in dose to organs at risk and acute toxicity levels was observed in IG-IMRT patients, as a result of improved technique and tighter margins. Therefore reduced late toxicity levels can be expected as well; additional research is needed to quantify such reductions., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Purpose: To use a high-quality multicenter trial dataset to determine dose-volume effects for gastrointestinal (GI) toxicity following radiation therapy for prostate carcinoma. Influential dose-volume histogram regions were to be determined as functions of dose, anatomical location, toxicity, and clinical endpoint., Methods and Materials: Planning datasets for 754 participants in the TROG 03.04 RADAR trial were available, with Late Effects of Normal Tissues (LENT) Subjective, Objective, Management, and Analytic (SOMA) toxicity assessment to a median of 72 months. A rank sum method was used to define dose-volume cut-points as near-continuous functions of dose to 3 GI anatomical regions, together with a comprehensive assessment of significance. Univariate and multivariate ordinal regression was used to assess the importance of cut-points at each dose., Results: Dose ranges providing significant cut-points tended to be consistent with those showing significant univariate regression odds-ratios (representing the probability of a unitary increase in toxicity grade per percent relative volume). Ranges of significant cut-points for rectal bleeding validated previously published results. Separation of the lower GI anatomy into complete anorectum, rectum, and anal canal showed the impact of mid-low doses to the anal canal on urgency and tenesmus, completeness of evacuation and stool frequency, and mid-high doses to the anorectum on bleeding and stool frequency. Derived multivariate models emphasized the importance of the high-dose region of the anorectum and rectum for rectal bleeding and mid- to low-dose regions for diarrhea and urgency and tenesmus, and low-to-mid doses to the anal canal for stool frequency, diarrhea, evacuation, and bleeding., Conclusions: Results confirm anatomical dependence of specific GI toxicities. They provide an atlas summarizing dose-histogram effects and derived constraints as functions of anatomical region, dose, toxicity, and endpoint for informing future radiation therapy planning., (Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.)

Objective: Radiation-induced anal toxicity can be induced by low radiation doses in patients with haemorrhoids. The object of this study was to determine the dosimetric benefits of different whole pelvic radiotherapy (WPRT) techniques in terms of dose delivered to the anal canal in post-operative patients with cervical cancer., Methods: The planning CT images of 10 patients with cervical cancer undergoing postoperative radiotherapy were used for comparison of three different plans. All patients had been treated using the conventional box technique WPRT (CV-WPRT), and we tried low-margin-modified WPRT (LM-WPRT), three-dimensional conformal techniques WPRT (CF-WPRT) and intensity-modulated WPRT (IM-WPRT) planning for dosimetric comparison of the anal canal, retrospectively., Results: Mean anal canal doses of the IM-WPRT were significantly lower (p < 0.05) than those of CV-WPRT, LM-WPRT and CF-WPRT, and V10, V20, V30 and V40 to the anal canal were also significantly lower for IM-WPRT (p < 0.05). The proportion of planning target volumes (PTVs) that received ≥98% of the prescribed dose for all plans was >99%, and the proportion that received ≥108% of the prescribed dose for IM-WPRT was <2%. Volumes of bladders and rectums that received ≥30 or ≥40 Gy were significantly lower for IM-WPRT than for three of the four-field WPRT plans (p = 0.000)., Conclusion: IM-WPRT can significantly reduce radiation dose delivered to the anal canal and does not compromise PTV coverage. In patients with haemorrhoids, IM-WPRT may be of value for the prevention of anal complications., Advances in Knowledge: Although tolerance of the anal canal tends to be ignored in patients undergoing post-operative WPRT, patients with haemorrhoids may suffer complications at low radiation doses. The present study shows IM-WPRT can be meaningful in these patients.

Aims and Background: Tolerance of the anal canal tends to be ignored in patients with cervical cancer undergoing whole pelvic radiotherapy. However, patients with hemorrhoids may be troubled with low radiation dose. We tried to analyze the dose-volume statistics of the anal canal in patients undergoing whole pelvic radiotherapy., Methods: The records of 31 patients with cervical cancer who received definite or postoperative radiotherapy at one institution were reviewed. Acute anal symptoms, such as anal pain and bleeding, were evaluated from radiotherapy start to 1 month after radiotherapy completion. Various clinical and dosimetric factors were analyzed to characterize relations with acute anal complications., Results: The anal verge was located an average of 1.2 cm (range -0.6~3.9) below the lower border of the ischial tuberosity and an average of 2.7 cm (range -0.6~5.7) behind the sacral promontory level. The presence of hemorrhoids before radiotherapy was found to be significantly associated with acute radiation-induced anal symptoms (p = 0.001), and the mean induction dose for anal symptoms was 36.9 Gy. No patient without hemorrhoids developed an anal symptom during radiotherapy. Dosimetric analyses of V30 and V40 showed marginal correlations with anal symptoms (p = 0.07)., Conclusions: The present study suggests a relation between acute anal symptoms following radiotherapy and acute hemorrhoid aggravation. Furthermore, the location of the anal verge was found to be variable, and consequently doses administered to the anal canal also varied substantially. Our results caution careful radiation treatment planning for whole pelvic radiotherapy, and that proper clinical management be afforded patients with hemorrhoids during radiotherapy.