[Normal tissue tolerance to external beam radiation therapy: anal canal]

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

BACKGROUND/AIM

Anal canal toxicity tends to be ignored in pelvic radiotherapy (RT). However, patients with hemorrhoids can be troubled by lower radiation dose. We tried to determine whether a correlation exists between hemorrhoids and anal symptoms in patients with cervical cancer undergoing RT.

PATIENTS AND METHODS

The insurance claim data of patients who underwent definitive treatment for cervical cancer from 2015 to 2019 were analyzed. Adverse events including bleeding, proctitis, and hemorrhoids, were documented for 1 year after treatment completion. Odds ratios (ORs) were estimated by unconditional Poisson regression and adjusted for age, treatments, chemotherapy, and comorbidities.

RESULTS

Details of 67,114 insured cervical cancer patients treated between 2015 and 2019 were obtained. Among them, 5,919 patients with follow-up data for at least one year, treated with curative intent, were analyzed. The OR of the definitive radiotherapy group (DRT group) for anal bleeding was 10.57 higher than that of the operation alone group (surgical group) (p<0.01). Newly developed hemorrhoids gradually increased in the surgical group (3.17%), the postoperative radiotherapy group (5.38%), and the DRT group (7.58%). The OR of the DRT group for newly developed hemorrhoids was 2.38 higher than that of the surgical group (p<0.01), and ORs increased to 1.99 and 1.61 in patients that received chemotherapy and patients with diabetes, respectively (p<0.01).

CONCLUSION

Pelvic RT increased anal bleeding and symptomatic hemorrhoids. In particular, chemotherapy and diabetes also increased the risk. If patients with hemorrhoids receive pelvic RT, attention is required to prevent hemorrhoid aggravation.

Late Gastrointestinal Tolerance After Prostate Radiotherapy: Is the Anal Canal the Culprit? A Narrative Critical Review

INTRODUCTION

Late gastro-intestinal toxicities (LGIT) secondary to pelvic radiotherapy (RT) are well described in the literature. LGIT are mainly related to rectal or ano-rectal irradiation; however, involvement of the anal canal (AC) in the occurrence of LGIT remains poorly described and understood.

MATERIALS AND METHODS

The aim of this work was to explore the potential role of the AC in the development of LGIT after prostate irradiation and identify predictive factors that could be optimized in order to limit these toxicities. This narrative literature review was realized using the Pubmed database. We identified original articles published between June 1997 and July 2019, relating to LGIT after RT for localized prostate cancer and for which AC was identified independently. Articles defining the AC as part of an anorectal or rectal volume only were excluded.

RESULTS

A history of abdominal surgery or cardio-vascular risk, anticoagulant or tobacco use, and the occurrence of acute GIT during RT increases the risk of LGIT. A dose-effect relationship was identified between dose to the AC and development of LGIT. Identification and contouring of the AC and adjacent anatomical structures (muscles or nerves) are justified to apply specific dose constraints. As a limitation, our review mainly considered on 3DCRT which is no longer the standard of care nowadays; we did not identify any reports in the literature using moderately hypofractionated RT for the prostate and AC specific dosimetry.

CONCLUSION

These results suggest that the AC may have an important role in the development of LGIT after pelvic RT for prostate cancer. The individualization of the AC during planning should be recommended in prospective studies.

Predictive factors of rectal hemorrhage in patients with localized prostate cancer who underwent low-dose-rate brachytherapy

BACKGROUND

This study aimed to evaluate the association between clinical covariates or the prescribed radiation dose for the prostate and rectal hemorrhage in patients with prostate cancer (PCa) who received iodine-125 low-dose-rate brachytherapy (LDR-BT group) or the combination of LDR-BT and external beam radiation therapy (CMT group).

METHODS AND MATERIALS

In this retrospective study, we reviewed the clinical records of 298 consecutive PCa patients with clinical stage T1c/T2 who underwent LDR-BT between August 2004 and August 2016 at a single institution. The prescribed minimum peripheral doses were 145 Gy for the LDR-BT group and 104 Gy for the CMT group. The dosimetric parameters analyzed were minimal dose received by 90% of the prostate gland, biologically effective dose, and rectal volume receiving 100% (RV100) or 150% of the prescribed dose. The endpoint of this study was the onset of any-grade clinical rectal hemorrhage after treatment.

RESULTS

The median follow-up period was 6.8 years. The 5-year overall survival rate was found to be 98.3%, and two patients (0.7%) reported biochemical recurrence during follow-up period. A total of 33 patients (11%) experienced rectal hemorrhage. However, ≥ grade 2 rectal hemorrhage occurred in eight patients (2.7%). On multivariate analysis, CMT, RV100 ≥ 0.66 mL, and hemorrhoids before treatment were identified as predictors of rectal hemorrhage after radiation therapy.

CONCLUSIONS

Maximal reduction of the rectal dose seems very important to prevent serious rectal hemorrhage. In addition, we should consider the risk of rectal toxicities in patients with abnormalities in the rectal mucosa, especially hemorrhoids.

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

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 Current Treatment of Squamous Cell Carcinoma of the Anus

In this review, a summary of our current understanding of squamous cell carcinoma of the anus (SCCA) and the advances in our knowledge of SCCA regarding screening, prevention, the role of the immune system, current treatment and the potential for novel targets are discussed. The present standard of care in terms of treatment is 5-fluorouracil (5-FU) and mitomycin C (MMC) concurrently with radiation, which results in a high level of disease control for small early cancers. Preservation of the anal sphincter is achieved in the majority, although anorectal function is often impaired. Although evidence from prospective studies to support a change in the treatment strategy is lacking, patients with HPV-negative SCCA appear to be less responsive to chemoradiation (CRT) and relapse more frequently. In contrast, HPV-positive tumours usually fare better, but oncological outcomes are modified by smoking and immune incompetence. There is current interest in escalating the radiotherapy dose for larger, more advanced tumours, and de-escalating treatment for HPV-positive tumours. The use of novel immunological treatments to target the underlying different molecular pathways of HPV-positive cancers is exciting.

Dosimetric planning study for the prevention of anal complications after post-operative whole pelvic radiotherapy in cervical cancer patients with hemorrhoids

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.

Acute anal toxicity after whole pelvic radiotherapy in patients with asymptomatic haemorrhoids: identification of dosimetric and patient factors

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 anal canal as a risk organ in cervical cancer patients with hemorrhoids undergoing whole pelvic radiotherapy

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.

External beam radiotherapy ± chemotherapy in the treatment of anal canal cancer: a single-institute long-term experience on 100 patients

One-hundred patients treated with curative radiotherapy (RT) ± chemotherapy (CT) for an anal canal carcinoma (T1-4N0-3M0) were retrospectively analyzed. Five- and 10-year local control (LC) rates were 73% and 67%, respectively. Acute and late G3-G4 toxicity rates were 32% and 12%, respectively. Two patients underwent a colostomy for a G4 anal toxicity. This study confirms the outcomes of RT ± CT in the treatment of anal canal cancer. Concomitant CT and LC statistically influenced Overall Survival and Colostomy-Free Survival. CT also statistically reduced the risk of nodal relapse. High rates of acute skin toxicity impose tailored volumes and techniques of irradiation.

Scrotal irradiation in primary testicular lymphoma: review of the literature and in silico planning comparative study

We examined adjuvant irradiation of the scrotum in primary testicular lymphoma (PTL) by means of a literature review in MEDLINE, a telephone survey among Dutch institutes, and an in silico planning comparative study on scrotal irradiation in PTL. We did not find any uniform adjuvant irradiation technique assuring a safe planning target volume (PTV) coverage in published reports, and the definition of the clinical target volume is unclear. Histopathologic studies of PTL show a high invasion rate of the tunica albuginea, the epididymis, and the spermatic cord. In retrospective studies, a prescribed dose of at least 30 Gy involving the scrotum is associated with best survival. The majority of Dutch institutes irradiate the whole scrotum without using a planning computed tomography scan, with a single electron beam and a total dose of 30 Gy. The in silico planning comparative study showed that all evaluated approaches met a D(95%) scrotal dose of at least 85% of the prescription dose, without exceeding the dose limits of critical organs. Photon irradiation with 2 oblique beams using wedges resulted in the best PTV coverage, with a mean value of 95% of the prescribed dose, with lowest maximum dose. Adjuvant photon or electron irradiation of the whole scrotum including the contralateral testicle with a minimum dose of 30 Gy is recommended in PTL. Computed tomography-based radiation therapy treatment planning with proper patient positioning and position verification guarantees optimal dose coverage.

[Intensity-modulated radiation therapy for anal carcinoma]

Anal canal carcinoma are highly curable by irradiation, combined with chemotherapy in locally advanced disease, with preservation of sphincter function. The clinical target volume for the nodes is extended, often including the inguinal nodes, which is not usual for other pelvic tumours. Acute and late effects are correlated with the volume and dose delivered to organs at risk, i. e. small bowel, bladder and increased by concomitant chemotherapy. Intensity modulated irradiation (IMRT) makes it possible to optimize the dose distribution in this "complex U shaped" volume, while maintaining the dose distribution for the target volumes. The conversion from conformal irradiation to IMRT necessitates good knowledge of the definition and skills to delineate target volumes and organs at risk, including new volumes needed to optimize the dose distribution. Dosimetric and clinical benefits of IMRT are described, based on early descriptions and evidence-based publication. The growing development of IMRT in anal canal radiotherapy must be encouraged, and long-term benefits should be soon published. Radiation oncologists should precisely learn IMRT recommendations before starting the technique, and evaluate its early and late results for adverse effects, but also for long-term tumour control.