Radiation colitis and proctitis

Radiation in Gastroenterology

The benefit of radiation is immense in the field of gastroenterology. Radiation is used daily in different gastrointestinal imaging and diagnostic and therapeutic interventional procedures. Radiotherapy is one of the primary modalities of treatment of gastrointestinal malignancies. There are various modalities of radiotherapy. Radiotherapy can injure malignant cells by directly damaging DNA, RNA, proteins, and lipids and indirectly by forming free radicals. External beam radiation, internal beam radiation and radio-isotope therapy are the major ways of delivering radiation to the malignant tissue. Radiation can also cause inflammation, fibrosis, organ dysfunction, and malignancy. Patients with repeated exposure to radiation for diagnostic imaging and therapeutic procedures are at slightly increased risk of malignancy. Gastrointestinal endoscopists performing fluoroscopy-guided procedures are also at increased risk of malignancy and cataract formation. The radiological protection society recommends certain preventive and protective measures to avoid side effects of radiation. Gastrointestinal complications related to radiation therapy for oncologic processes, and exposure risks for patients and health care providers involved in diagnostic or therapeutic imaging will be discussed in this review.

Response Evaluation Following Radiation Therapy With 18F-FDG PET/CT: Common Variants of Radiation-Induced Changes and Potential Pitfalls

Radiation therapy (RT) is one of the cornerstones in cancer treatment and approximately half of all patients will receive some form of RT during the course of their cancer management. Response evaluation after RT and follow-up imaging with ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) can be complicated by RT-induced acute, chronic or consequential effects. There is a general consensus that ¹⁸F-FDG PET/CT for response evaluation should be delayed for 12 weeks after completing RT to minimize the risk of false-positive findings. Radiation-induced late side effects in normal tissue can take years to develop and eventually cause symptoms that on imaging can potentially mimic recurrent disease. Imaging findings in radiation induced injuries depend on the normal tissue included in the irradiated volume and the radiation therapy regime including the total dose delivered, dose per fraction and treatment schedule. The intent for radiation therapy should be taken in consideration when evaluating the response on imaging, that is palliative vs curative or neoadjuvant vs adjuvant RT. Imaging findings can further be distorted by altered anatomy and sequelae following surgery within the radiation field. An awareness of common PET/CT-induced changes/injuries is essential when interpreting ¹⁸F-FDG PET/CT as well as obtaining a complete medical history, as patients are occasionally scanned for an unrelated cause to previously RT treated malignancy. In addition, secondary malignancies due to carcinogenic effects of radiation exposure in long-term cancer survivors should not be overlooked. ¹⁸F-FDG PET/CT can be very useful in response evaluation and follow-up in patients treated with RT, however, variants and pitfalls are common and it is important to remember that radiation-induced injury is often a diagnosis of exclusion.

Therapeutics in Radiation-induced Proctopathy: A Systematic Review

Malignant neoplasms are increasingly prevalent in the daily clinical practice. Up to 61% of patients with pelvic malignancies undergo pelvic radiotherapy in different doses, which may cause intestinal damage, and the rectum is the segment most frequently affected due to its fixed position in the pelvis. Currently, there are several strategies to minimize the effects of radiation on the tissues surrounding the neoplastic site; despite those strategies, radiotherapy can still result in serious damage to organs and structures, and these injuries accompany patients throughout their lives. One of the most common damages resulting from pelvic radiotherapy is acute proctitis.The diagnosis is confirmed by visualizing the rectal mucosa through rigid or flexible rectosigmoidoscopy and colonoscopy. The objective of the present study was to review the forms of radiation-induced proctopathytherapy, and to evaluate the results of each method to propose a standardization for the treatment of this pathology. Despite the prevalence of radiation-induced proctopathy, there is no definitive standardized treatment strategy so far. The first approach can be tried with local agents, such as mesalazine and formalin. For refractory cases, control can usually be achieved with argon plasma coagulation, hyperbaric oxygen, and radiofrequency ablation therapies. Regarding the study of radiation-induced proctopathy, there is a lack of robust studies with large samples and standardized therapies to be compared. There is a lack of double-blinded, randomized controlled studies to determine a definitive standard treatment algorithm.

Patient-related risk factors for late rectal bleeding after hypofractionated radiotherapy for localized prostate cancer: a single-center retrospective study

Background

Several studies have reported patient-related risk factors for late rectal bleeding following conventionally fractionated radiotherapy for prostate cancer. We investigated patient-related risk factors for late rectal bleeding after hypofractionated radiotherapy.

Methods

A total of 231 patients with local or locally advanced prostate cancer treated with hypofractionated radiotherapy (70 or 67.2 Gy in 28 fractions) were evaluated retrospectively. All patients received intensity-modulated radiotherapy with daily image guidance. The relationships between late rectal bleeding and risk factors like diabetes, hypertension, cirrhosis, and anticoagulant use were analyzed.

Results

During a median follow-up of 23 months, the crude rates of grade ≥ 1, grade ≥ 2, and grade ≥ 3 late rectal bleeding were 23.8%, 16.9%, and 9.5%, respectively. Cirrhosis and anticoagulant use predicted an increased risk of grade ≥ 3 rectal bleeding in multivariable analyses (hazard ratio [HR] 14.37, 95% confidence interval [CI] 3.09–66.87, P = 0.001, and HR 2.93, 95% CI 1.14–7.55, P = 0.026, respectively). The non-anticoagulant group had a significantly superior 5-year freedom from grade ≥ 3 bleeding compared to the anticoagulant group in a propensity-weighted log-rank analysis (88.0% vs. 76.7%, P = 0.041). A receiver operating characteristic curve analysis revealed that rectal bleeding was minimized in the anticoagulant group if the equivalent dose at fractionation of 2 Gy (EQD2) V77 Gy of the rectum was < 4.5% or if the EQD2 V8.2 Gy was < 71.0%.

Conclusions

Patients taking anticoagulants or those with cirrhosis had a significantly higher risk of severe late rectal bleeding than other patients after hypofractionated radiotherapy for prostate cancer in the present study. The bleeding risk could be lowered by minimizing hotspots in patients taking anticoagulants.

Radiation Proctitis and Management Strategies

Radiotherapy (RT) is a treatment modality that uses high-energy rays or radioactive agents to generate ionizing radiation against rapidly dividing cells. The main objective of using radiation in cancer therapy is to impair or halt the division of the tumor cells. Over the past few decades, advancements in technology, the introduction of newer methods of RT, and a better understanding of the pathophysiology of cancers have enabled physicians to deliver doses of radiation that match the exact dimensions of the tumor for greater efficacy, with minimal exposure of the surrounding tissues. However, RT has numerous complications, the most common being radiation proctitis (RP). It is characterized by damage to the rectal epithelium by secondary ionizing radiation. Based on the onset of signs and symptoms, post-radiotherapy RP can be classified as acute or chronic, each with varying levels of severity and complication rates. The treatment options available for RP are limited, with most of the data on treatment available from case reports or small studies. Here, we describe the types of RT used in modern-day medicine and radiation-mediated tissue injury. We have primarily focused on the classification, epidemiology, pathogenesis, clinical features, treatment strategies, complications, and prognosis of RP.

Personalized Radiation Attenuating Materials for Gastrointestinal Mucosal Protection

Cancer patients undergoing therapeutic radiation routinely develop injury of the adjacent gastrointestinal (GI) tract mucosa due to treatment. To reduce radiation dose to critical GI structures including the rectum and oral mucosa, 3D-printed GI radioprotective devices composed of high-Z materials are generated from patient CT scans. In a radiation proctitis rat model, a significant reduction in crypt injury is demonstrated with the device compared to without (p < 0.0087). Optimal device placement for radiation attenuation is further confirmed in a swine model. Dosimetric modeling in oral cavity cancer patients demonstrates a 30% radiation dose reduction to the normal buccal mucosa and a 15.2% dose reduction in the rectum for prostate cancer patients with the radioprotectant material in place compared to without. Finally, it is found that the rectal radioprotectant device is more cost-effective compared to a hydrogel rectal spacer. Taken together, these data suggest that personalized radioprotectant devices may be used to reduce GI tissue injury in cancer patients undergoing therapeutic radiation.

Management of Long-Term Toxicity From Pelvic Radiation Therapy

Pelvic radiation therapy is an integral component in the treatment of various gastrointestinal, gynecologic, and genitourinary cancers. As survival rates from these malignancies improve, the prevalence of toxicity secondary to pelvic radiation has increased. Gastrointestinal toxicities are the most common complications and greatly impact quality of life. Toxicities can present in acute or late stages; although symptoms may be similar during both, the management may differ. Acute toxicities represent an inflammatory reaction in response to the radiation exposure, whereas late toxicities may arise as a result of small vessel disease, ischemia, and fibrosis. Currently, there are no large clinical trials and only limited guidelines on the management of late gastrointestinal radiation toxicities. Therapy is generally approached in a stepwise manner from medical to endoscopic to surgical methods. Several endoscopic therapies, such as the treatment of radiation proctitis with argon plasma coagulation and dilation of radiation bowel strictures, may prevent the need for surgical intervention, which may be associated with high morbidity and mortality. Given that late toxicities can occur years after radiation therapy, they are often difficult to recognize and diagnose. Successful management of late toxicities requires recognition, an understanding of the underlying pathophysiology, and a multidisciplinary approach. More dedicated research could clarify the prevalence of gastrointestinal pelvic radiation toxicities, permit a better understanding of the efficacy and safety profile of current therapies, and allow for the development of novel therapeutic approaches.

Gastrointestinal side effects of cancer treatments

Cancer survival rates have significantly improved over the last number of years due to advancements in cancer therapies. Unfortunately this has come at a cost. Therapeutic side effects are feared complications of therapy that may result in decreased quality of life and early cessation of the therapy, which can have knock-on effects on outcomes. This article outlines the main gastrointestinal side effects seen with radiation therapy, chemotherapy and immunotherapy, and discusses appropriate investigation and management.

Multi-slice spiral CT evaluation of chronic radiation colitis and rectitis

The aim of the present study was to retrospectively analyse the multi-slice spiral CT (MSCT) findings of radiation colitis and rectitis (RC&R). A total of 23 cases of RC&R detected by helical CT were included. The CT findings and clinical and endoscopy data of the patients were reviewed. The primary tumours included cancers of the cervix (n=17), rectum (n=4), ovaries (n=1) and bladder (n=1). The total dose of radiation per patient was 46-60 Gy (mean, 49.7 Gy) delivered over 5 weeks. The CT manifestations included different degrees of increased thickness of the intestinal wall (n=20, 87.0%), with a maximum thickness of 16.6 mm. On enhanced CT, the target sign was observed (n=16, 69.9%), with an obviously enhanced mucosa and/or serosa and the following changes observed: Oedema and increased density of the mesentery (n=15, 65.2%); increased density of the subcutaneous fat, and blurred and oedematous pelvic wall muscles (n=4, 17.4%), with the obturator internus and levator ani muscles being most commonly affected; narrowed intestinal lumen (n=3, 13.0%); and a small amount of ascitic fluid (n=2, 8.7%) located in the paracolic sulci and bladder or Douglas pouch. The 23 patients underwent colonoscopy and were diagnosed with RC&R. The major manifestations included telangiectasia and mucosal hyperaemia (n=21, 91.3%). MSCT of chronic RC&R (CRC&R) was associated with certain characteristic findings, which, combined with a medical history of radiotherapy and the clinical manifestations, may prove to be of value in the diagnosis of CRC&R.

Radiation enteritis: Diagnostic and therapeutic issues

Abdominal pelvic radiation therapy can induce acute or chronic lesions in the small bowel wall, called radiation enteritis. Treatment of acute radiation enteritis is essentially symptomatic; symptoms regress when radiation is discontinued. Conversely, late toxicity can occur up to 30 years after discontinuation of radiation therapy, posing diagnostic problems. Approximately one out of five patients treated by radiation therapy will present clinical signs of radiation enteritis, including obstruction, malabsorption, malnutrition and/or other complications. Management should be multidisciplinary, centered mainly on correction of malnutrition. Surgery is indicated in case of complications (i.e., abscess, perforation, fistula) and/or resistance to medical treatment; intestinal resection should be preferred over internal bypass. The main risk in case of iterative resections is the short bowel syndrome and the need for definitive nutritional assistance.

Endoscopical and pathological dissociation in severe colitis induced by immune-checkpoint inhibitors

Checkpoint inhibitors have improved the survival of patients with advanced tumors and show a manageable toxicity profile. However, auto-immune colitis remains a relevant side effect, and combinations of anti-PD1/PDL1 and anti-CTLA-4 increase its incidence and severity. Here, we report the case of a 50-year-old patient diagnosed with stage IV cervical cancer that relapsed following radical surgery, external radiation/brachytherapy and standard chemotherapy. She was subsequently treated with Nivolumab and Ipilimumab combination and developed grade 2 colitis presenting a dissociation between endoscopic and pathological findings. At cycle 10 the patient reported grade 3 diarrhea and abdominal discomfort, without blood or mucus in the stools. Immunotherapy was withheld and a colonoscopy was performed, showing normal mucosa in the entire colon. Puzzlingly, histologic evaluation of randomly sampled mucosal biopsy of the distal colon showed an intense intraepithelial lymphocyte infiltration with crypt loss and some regenerating crypts with a few apoptotic bodies set in a chronically inflamed lamina propria, consistent with the microscopic diagnosis of colitis. Treatment with methylprednisolone 2 mg/kg was initiated which led to a decrease in the number of stools to grade 1. Additional investigations to exclude other causes of diarrhea rendered negative results. The patient experienced a major partial response and, following the resolution of diarrhea, she was re-challenged again with immunotherapy, with the reappearance of grade 2 diarrhea, leading to permanent immunotherapy interruption. We conclude and propose that performing random colonic biopsies should be considered in cases of immune checkpoint-associated unexplained diarrhea, even when colonoscopy shows macroscopically normal colonic mucosa inflammatory lesions.

Clostridium difficile colitis: CT findings and differential diagnosis

Clostridium difficile infection (CDI) is a severe and potentially deadly infectious colitis whose incidence is dramatically increasing in the last decades, with more virulent strains. CDI should be suspected in case of unexplained diarrhea and abdominal pain in patients with a recent history of antibiotic use and healthcare exposures; diagnosis is based on a combination of clinical and laboratory findings with demonstration of C. difficile toxins by stool test. The advantages of contrast-enhanced computed tomography (CECT) are the noninvasiveness and the ability to evaluate both the colonic wall and the adjacent soft tissues. Considerable overlap exists between the CECT findings of CDI and those of colitis of other origins, such as typhlitis, ischemic colitis, graft-versus-host disease, radiation colitis and inflammatory bowel diseases; however, some features may help distinguish between these conditions. This paper provides a comprehensive overview of the imaging features of Clostridium difficile colitis and its mimics, with a view to assist the radiologist in reaching the correct diagnosis.

LncRNA WWC2-AS1 functions AS a novel competing endogenous RNA in the regulation of FGF2 expression by sponging miR-16 in radiation-induced intestinal fibrosis

BACKGROUND

Recently, long non-coding RNAs (lncRNAs) were considered as important gene expression regulators involving various biological processes. In this study, we explored the role of lncRNAs in the pathogenesis of radiation-induced intestinal fibrosis (RIF).

METHODS

LncRNAs were screened by microarray (Human LncRNA Array v3.0, Arraystar, Inc.) and the differentially expressed lncRNAs in RIF and non-RIF were analyzed by bioinformatics methods. The expression of WWC2-AS1/miR-16/FGF2 axis was compared on mRNA and protein level between human intestinal CCD-18Co fibroblasts cell lines and subepithelial SEMFs in response to radiation treatment. The significance of WWC2-AS1 in regulating FGF2 associated proliferation, migration, invasion and fibrosis of CCD-18Co and SEMFs by exposure to radiation was analyzed by shRNA (WWC2-AS1 shRNA) knock-down of endogenous WWC2-AS1.

RESULTS

WWC2-AS1 and FGF2 level was significantly higher while miR-16 was down-regulated in radiation-treated intestinal tissues. WWC2-AS1 more potently boosted FGF2 expression via reducing miR-16, and WWC2-AS1 shRNA remarkably inhibited FGF2 associated proliferation, migration, invasion and fibrosis of radiation treatment in vitro, further demonstrating physical interaction between miR-16 and WWC2-AS1 in radiation-induced fibrosis progress.

CONCLUSIONS

WWC2-AS1 was highly expressed in RIF, may function as a ceRNA in the regulation of FGF2 by binding miR-16. Targeting WWC2-AS1 thus may benefit radiation-induced fibrosis treatment.

Prone Positioning on a Belly Board Decreases Rectal and Bowel Doses in Pelvic Intensity-Modulated Radiation Therapy (IMRT) for Prostate Cancer

The presence of normal tissues in the irradiated volume limits dose escalation during pelvic radiotherapy (RT) for prostate cancer. Supine and prone positions on a belly board were compared by analyzing the exposure of organs at risk (OARs) using intensity modulated RT (IMRT). The prospective trial included 55 high risk, localized or locally advanced prostate cancer patients, receiving definitive image-guided RT. Computed tomography scanning for irradiation planning was carried out in both positions. Gross tumor volume, clinical and planning target volumes (PTV) and OARs were delineated, defining subprostatic and periprostatic rectal subsegments. At the height of the largest antero-posterior (AP) diameter of the prostate, rectal diameters and distance from the posterior prostate wall were measured. IMRT plans were generated. Normal tissue exposure and structure volumes were compared between supine and prone plans using paired t-test. In the volumes of the prostate, PTV, colon and small bowel, no significant differences were found. In prone position, all rectal volumes, diameters, and rectum-prostate distance were significantly higher, the irradiated colon and small bowel volume was lower in dose ranges of 20-40 Gy, and the exposure to all rectal segments was more favorable in 40-75 Gy dose ranges. No significant difference was found in the exposure of other OARs. Prone positioning on a belly board is an appropriate positioning method aiming rectum and bowel protection during pelvic IMRT of prostate cancer. The relative reduction in rectal exposure might be a consequence of the slight departure between the prostate and rectal wall.

Expression of vascular endothelial growth factor and its correlation with clinical symptoms and endoscopic findings in patients with chronic radiation proctitis

AIM

The aim of this study was to assess the expression of vascular endothelial growth factor (VEGF) as a key proangiogenic factor and determine whether there is any correlation between its expression and clinical symptoms or endoscopic changes in patients with chronic radiation proctitis (ChRP).

METHOD

Fifty patients who had all undergone radiotherapy for prostate, cervical or uterine cancer were included in the study (37 women, 13 men). There was a control group of 20 patients (9 women, 11 men). The Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer (RTOG/EORTC) scoring system was used for grading the severity of the proctitis. Endoscopic scoring of late rectal mucosal damage was performed using Gilinsky's classification. Serum levels of VEGF were analysed by the enzyme-linked immunosorbent assay method.

RESULTS

Most patients presented with Grade 1 symptoms. Endoscopic assessment showed that most patients had Grade 1 late rectal mucosal damage. The predominant endoscopic finding was the presence of telangiectasia. Assessment of VEGF correlation between the control group and the degrees of endoscopic changes showed statistically significant differences for all three degrees (P < 0.0001, P = 0.0251 and P = 0.0005, respectively). Due to the small numbers of patients with Grades 2 and 3 symptoms using the RTOG/EORTC scoring system, they were grouped with Grades 1 and 4 respectively forming two groups for statistical purposes. VEGF expression differed significantly between controls and group I and between controls and group II (P = 0.0001, P = 0.0009, respectively).

CONCLUSION

A significant increase in VEGF expression was found to correlate with clinical symptoms and endoscopic rectal mucosa changes in patients with ChRP, suggesting that it may play an important role in pathological angiogenesis.

Role of Angiogenesis in Chronic Radiation Proctitis: New Evidence Favoring Inhibition of Angiogenesis Ex Vivo

BACKGROUND

Chronic radiation proctitis (CRP), a common complication after radiotherapy for pelvic malignancies, compromises patient quality of life. Vascular damage and aberrant angiogenesis in the mucosal layer are essential histological features, but changes to the submucosal layer are unclear. Thus, we evaluated the histological characteristics and distribution changes of key angiogenic factors in full-layered human CRP samples.

METHODS

Thirty paraffin-embedded CRP and twenty-nine non-CRP tissues were used to evaluate histopathological changes. Immunohistochemistry with anti-CD34 antibody was performed to calculate microvascular density (MVD). Frozen tissues from eight CRP patients and five non-CRP controls were collected and analyzed by antibody array, which contained sixty human angiogenesis-related factors. Quality controls with positive and negative controls were performed during antibody array analysis. Two differentially expressed factors were confirmed by ELISA.

RESULTS

CRP lesions showed vasculopathy, fibrosis, mucosal ulceration, edema, and inflammatory cell infiltration. Human angiogenesis antibody array and ELISA confirmed the increased angiostatin in CRP lesions. Immunohistochemical staining showed dispersed distribution of angiostatin throughout the mucosal and submucosal layers in CRP lesions, while angiostatin accumulated within the vessel lumens in non-CRP tissues. MVD significantly decreased in the submucosal layer of CRP, suggesting a potential association with increased angiostatin.

CONCLUSIONS

Angiostatin increased and had a distinct distribution in CRP lesions. Compensatory telangiectasia in the mucosa, vessel stenosis, and reduced MVD might attenuate blood flow in the submucosa and contribute to CRP progression. Restoration of vascular functionality by promoting angiogenesis in the submucosal layer may help alleviate CRP in clinical practice.

Imaging of acute anorectal conditions with CT and MRI

Anorectal disorders are a common cause of presentation to the emergency department (ED). While the most frequently encountered anorectal conditions, such as hemorrhoids and anal fissures, are relatively benign and do not require imaging for diagnosis or management, there are multiple potentially life threatening anorectal conditions for which imaging is an important component of evaluation, diagnosis, and management. Although computed tomography (CT) is the most commonly used imaging modality for evaluation of anorectal pathology in the ED, magnetic resonance imaging (MRI) has an increasingly important role in the detection, characterization and management of specific anorectal conditions. This pictorial essay will review the imaging anatomy of the anorectum, summarize imaging protocols, and discuss the clinical presentation, imaging appearance, and differential diagnosis of anorectal conditions that may present to the emergency department, including infectious, inflammatory, malignant and vascular conditions.

Iatrogenic pathology of the intestines

Many drugs and chemical agents can cause enteritis and colitis, producing clinical gastrointestinal side effects, the most common of which are diarrhoea, constipation, nausea and vomiting. Significant histological overlap exists between some patterns of medication or chemical injury and various disease entities. A particular medication may cause multiple patterns of injury and may mimic common entities such as coeliac disease, Crohn's disease, infectious enteritis and colitis. Thus, given the common absence of specific histopathological features, the diagnosis often relies upon thorough clinicopathological correlation. This review concentrates on selected examples of medication-induced injury of the intestinal tract in which the pathology can be recognized, particularly on biopsies, with a focus on newly described medication-induced gastrointestinal effects.

The potential of mesenchymal stem cells in the management of radiation enteropathy

Although radiotherapy is effective in managing abdominal and pelvic malignant tumors, radiation enteropathy is still unavoidable. This disease severely affects the quality of life of cancer patients due to some refractory lesions, such as intestinal ischemia, mucositis, ulcer, necrosis or even perforation. Current drugs or prevailing therapies are committed to alleviating the symptoms induced by above lesions. But the efficacies achieved by these interventions are still not satisfactory, because the milieus for tissue regeneration are not distinctly improved. In recent years, regenerative therapy for radiation enteropathy by using mesenchymal stem cells is of public interests. Relevant results of preclinical and clinical studies suggest that this regenerative therapy will become an attractive tool in managing radiation enteropathy, because mesenchymal stem cells exhibit their pro-regenerative potentials for healing the injuries in both epithelium and endothelium, minimizing inflammation and protecting irradiated intestine against fibrogenesis through activating intrinsic repair actions. In spite of these encouraging results, whether mesenchymal stem cells promote tumor growth is still an issue of debate. On this basis, we will discuss the advances in anticancer therapy by using mesenchymal stem cells in this review after analyzing the pathogenesis of radiation enteropathy, introducing the advances in managing radiation enteropathy using regenerative therapy and exploring the putative actions by which mesenchymal stem cells repair intestinal injuries. At last, insights gained from the potential risks of mesenchymal stem cell-based therapy for radiation enteropathy patients may provide clinicians with an improved awareness in carrying out their studies.

The protective effects of apocynin on ionizing radiation-induced intestinal damage in rats

BACKGROUND AND AIMS

Radiation colitis typically emerges during radiotherapy of intra-abdominal malignancies. While the underlying mechanism remains unclear, it is considered that free oxygen radicals act like cellular mediators to cause colonic damage. Apocynin (APO) prevents oxidative stress and apoptotic cell death by inhibiting NADPH oxidase, and preventing the formation of free oxygen radicals. The aim of the present study was to investigate the protective effect of APO, a strong antioxidant and antiinflammatory agent, on radiation induced colonic oxidative damage in rats.

MATERIALS AND METHODS

Rats were randomly divided into four groups (n = 8/group). Group I (control group); Group II (Group RAD) received a single dose of 800 cGy ionizing radiation to the whole abdomen with a linear accelerator (LINAC); Group III (Group APO) received a single dose of 20 mg/kg of APO intraperitoneally for five days; Group IV (Group APO+RAD) received APO for five days before radiation exposure (similar to Group III), (similar to Group II).

RESULTS

APO treatment prior to radiation led to protection in the biochemical and histopathological parameters.

CONCLUSIONS

Our study shows that APO treatment before radiation improves radiation induced colonic injury in rats, by decreasing oxidative stress and apoptosis.

Radiation proctopathy

Radiation therapy is a widely utilized treatment modality for pelvic malignancies, including prostate cancer, rectal cancer, and cervical cancer. Given its fixed position in the pelvis, the rectum is at a high risk for injury secondary to ionizing radiation. Despite advances made in radiation science, up to 75% of the patients will suffer from acute radiation proctitis and up to 20% may experience chronic symptoms. Symptoms can be variable and include diarrhea, bleeding, incontinence, and fistulization. A multitude of treatment options exist. This article summarizes the latest knowledge relating to radiation proctopathy focusing on the vast array of treatment options.

Formalin therapy for hemorrhagic radiation proctitis

BACKGROUND

Radiotherapy within pelvis is a vital component of curative therapy for urological, gynecological and rectal malignances. Rectum is especially vulnerable to secondary radiation injury resulting in proctitis. The most common and life-threatening symptom is rectal hemorrhage. Formalin application into the rectum causes local cauterization of telangiectatic mucosal vessels. The aim of our study was to assess the efficacy of local formalin application in patients with hemorrhagic radiation proctitis.

METHODS

A solution of 4.0% formalin was used in the treatment of 20 patients with clinical and proctoscopic evidence of radiadion proctitis. Treatment involved direct application of 4.0% formalin into the rectum. All patients were followed-up in terms of complete resolution of symptoms or recurrences of bleeding.

RESULTS

A total of 20 patients with a mean age of 69.7 (range, 57-80) years were followed for 51.2 (range, 1-93) months. The mean duration of symptoms was 4.5 (range, 1-10) months and the interval between the end of radiotherapy and symptoms was mostly between 5 and 30 months. Patients required an average of 2 (range, 1-5) formalin treatments. Of the 20 patients, 10 had complete resolution of their symptoms after their first treatment. In 10 patients bleeding recurred and they were offered another formalin instillation and/or 5-ASA suppositories and argon therapy. Complete resolution of symptoms was achieved in all patients.

CONCLUSIONS

Topical formalin instillation is effective, safe, and well-tolerated method for the patients with radiation proctopathy. This therapy may be repeated in case of recurrent bleeding and combined with other methods of treatment.

Radiation enteritis

Radiation enteritis continues to be a major health concern in recipients of radiation therapy. The incidence of radiation enteritis is expected to continue to rise during the coming years paralleling the unprecedented use of radiotherapy in pelvic cancers. Radiation enteritis can present as either an acute or chronic syndrome. The acute form presents within hours to days of radiation exposure and typically resolves within few weeks. The chronic form may present as early as 2 months or as long as 30 years after exposure. Risk factors can be divided into patient and treatment-related factors. Chronic radiation enteritis is characterized by progressive obliterative endarteritis with exaggerated submucosal fibrosis and can manifest by stricturing, formation of fistulae, local abscesses, perforation, and bleeding. In the right clinical context, diagnosis can be confirmed by cross-sectional imaging, flexible or video capsule endoscopy. Present treatment strategies are directed primarily towards symptom relief and management of emerging complications. Recently, however, there has been a shift towards rational drug design based on improved understanding of the molecular basis of disease in an effort to limit the fibrotic process and prevent organ damage.

Radiation-induced small bowel disease: latest developments and clinical guidance

Ionizing radiation is commonly used to treat a number of malignancies. Although highly effective and now more targeted, many patients suffer side effects. The number of cancer survivors has increased and so there are more patients presenting with symptoms that have arisen as a result of radiotherapy. Radiation damage to small bowel tissue can cause acute or chronic radiation enteritis producing symptoms such as pain, bloating, nausea, faecal urgency, diarrhoea and rectal bleeding which can have a significant impact on patient's quality of life. This review outlines the pathogenesis of radiation injury to the small bowel along with the prevention of radiation damage via radiotherapy techniques plus medications such as angiotensin-converting enzyme inhibitors, statins and probiotics. It also covers the treatment of both acute and chronic radiation enteritis via a variety of medical (including hyperbaric oxygen), dietetic, endoscopic and surgical therapies.

Chronic radiation enteritis and malnutrition

Radiation enteritis is defined as the loss of absorptive capacity of the intestine following irradiation, which is most commonly seen after radiotherapy for pelvic and abdominal malignancies. It is divided into acute and chronic forms and usually presents with diarrhea and malabsorption. Malnutrition is a common complication of chronic radiation enteritis (CRE). We reviewed the etiology, prevalence, symptoms, diagnosis and management of CRE and CRE with malnutrition in this article. Functional short bowel syndrome as a cause of malnutrition in CRE is also considered. The diagnostic work-up includes serum markers, endoscopy, cross-sectional imaging and the exclusion of alternative diagnoses such as recurrent malignancy. Management options of CRE include dietary manipulation, anti-motility agents, electrolyte correction, probiotics, parenteral nutrition, surgical resection and small bowel transplantation. Treatment may also be required for coexisting conditions including vitamin B12 deficiency, bile acid malabsorption and depression.

Endoscopic findings of rectal mucosal damage after pelvic radiotherapy for cervical carcinoma: correlation of rectal mucosal damage with radiation dose and clinical symptoms

PURPOSE

To describe chronic rectal mucosal damage after pelvic radiotherapy (RT) for cervical cancer and correlate these findings with clinical symptoms and radiation dose.

MATERIALS AND METHODS

Thirty-two patients who underwent pelvic RT were diagnosed with radiation-induced proctitis based on endoscopy findings. The median follow-up period was 35 months after external beam radiotherapy (EBRT) and intracavitary radiotherapy (ICR). The Vienna Rectoscopy Score (VRS) was used to describe the endoscopic findings and compared to the European Organization for Research and Treatment of Cancer (EORTC)/Radiation Therapy Oncology Group (RTOG) morbidity score and the dosimetric parameters of RT (the ratio of rectal dose calculated at the rectal point [RP] to the prescribed dose, biologically effective dose [BED] at the RP in the ICR and EBRT plans, α/β = 3).

RESULTS

Rectal symptoms were noted in 28 patients (rectal bleeding in 21 patients, bowel habit changes in 6, mucosal stools in 1), and 4 patients had no symptoms. Endoscopic findings included telangiectasia in 18 patients, congested mucosa in 20, ulceration in 5, and stricture in 1. The RP ratio, BEDICR, BEDICR+EBRT was significantly associated with the VRS (RP ratio, median 76.5%; BEDICR, median 37.1 Gy3; BEDICR+EBRT, median 102.5 Gy3; p < 0.001). The VRS was significantly associated with the EORTC/RTOG score (p = 0.038).

CONCLUSION

The most prevalent endoscopic findings of RT-induced proctitis were telangiectasia and congested mucosa. The VRS was significantly associated with the EORTC/RTOG score and RP radiation dose.

Radiation-induced distal ileal obstruction complicating ileostomy closure

BACKGROUND

Radiation enteropathy is a recognized complication in patients who undergo neoadjuvant radiotherapy for locally advanced rectal cancer. Routine formation of defunctioning loop ileostomy in these patients may mask the development of stricturing, terminal ileal and radiation enteropathy which later may complicate the ileostomy closure. Our aim was to assess the preventive techniques and key warning signs.

METHODS

We present two cases of ileostomy closure in patients with occult, radiation-induced, terminal ileal stricture and review the relevant literature.

RESULTS

The first case was complicated by dehiscence of the ileal anastomosis due to undiagnosed, downstream stenosis of the irradiated terminal ileum. A similar terminal ileal stricture was diagnosed in the second case by contrast fluoroscopy enabling an elective ileocolic anastomosis. The literature indicates the importance of identifying such problems prior to loop ileostomy closure.

CONCLUSIONS

Contrast studies before loop ileostomy closure are valuable in limiting the complications of radiation-induced distal ileal obstruction in selected patients.

Gene expression analysis in chronic postradiation proctopathy

PURPOSE

Radiotherapy is one of the important treatment modalities for tumors of pelvic organs. The fixed location of the rectum and its anatomic relationship with other pelvic organs makes it prone to radiation injury resulting in chronic radiation proctopathy in 5% to 20% of patients. Endothelial dysfunction has been associated with a number of pathophysiological processes. Endothelial cells synthesize and release various factors that regulate angiogenesis, inflammatory responses, hemostasis, as well as vascular tone and permeability.

METHODS

Rectum tissue samples from 20 patients with established chronic radiation proctopathy were analysed for the expression of genes related to oxidative stress, tissue hypoxia, angiogenesis, and inflammation [endoglin (ENG), activin receptor-like kinase 1 (ALK1), platelet endothelial cell adhesion molecule 1 (PECAM), vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), hypoxia-inducible factor 1 (HIF-1), and interleukin-1 beta (IL-1β)].

RESULTS

Overexpression of HIF-1, VEGF, FGF2, and IL-1β was detected in affected tissue. For the first time, a significant suppression of activin receptor-like kinase 1 and ENG could be revealed.

CONCLUSION

The data provided here allow further insight into the pathogenesis of radiation-induced rectum injury. Radiation-induced damage is not confined to a single event but involves complex signaling between different pathways, enhancing and maintaining the processes that lead to mucosal damage. The results indicate that postradiation tissue hypoxia is critical for fibrosis, which involves changes in the expression of profibrotic and angiogenic factors in rectal tissue.

Endoscopic assessment of inflammatory bowel disease: colonoscopy/esophagogastroduodenoscopy

Endoscopy plays an important role in the initial diagnosis of IBD, including the evaluation of disease severity, activity, and extent. The implications of complete mucosal healing further confirm the function of endoscopy in the follow-up of IBD patients. The use of therapeutic endoscopy, for example stricture dilatation, can avoid the need for bowel resection. Modalities such as capsule endoscopy, EUS, NBI, CE, and other emerging techniques are likely to have an increasing role in the management of IBD, particularly in the area of dysplasia surveillance and treatment.

Efficacy and safety of single-session argon plasma coagulation in the management of chronic radiation proctitis

BACKGROUND

Chronic radiation proctitis (CRP) manifests as rectal bleeding 12 to 24 months after pelvic radiotherapy. No criterion standard of treatment has been established, although argon plasma coagulation (APC) has increasingly become the treatment of choice. Previous studies have applied APC over multiple sessions, necessitating increased numbers of treatments.

OBJECTIVE

To assess the safety and efficacy of large-volume APC application in the treatment of CRP with the intention of a single-session treatment protocol.

DESIGN

Prospective study.

SETTING

Tertiary referral hospital.

PATIENTS

Over an 8-year period, consecutive patients with CRP with rectal bleeding were prospectively enrolled.

INTERVENTION

Large-volume APC application to affected rectal mucosa.

MAIN OUTCOME MEASUREMENTS

Number of treatments, bleeding scores, complications.

RESULTS

Fifty patients (mean age 72.1 years; range 51-87 years) were treated; 45 were men (prostate cancer). The mean period between radiotherapy and initial APC treatment was 23 months (range 4-140 months). Seventeen (34%) patients had grade A endoscopic severity, 23 (46%) grade B, and 10 (20%) grade C. Other therapies failed in 16 (32%) patients. The mean number of treatments was 1.36 (range 1-3) with a mean follow-up of 20.6 months (range 6-48 months). Sixty-eight percent of patients were successfully treated after 1 session and 96% after 2 sessions. Bleeding scores improved in all patients (P < .001). Seventeen (34%) patients experienced short-term, self-limiting complications; 1 (2%) patient experienced a long-term complication.

LIMITATIONS

Nonrandomized study.

CONCLUSIONS

Large-volume APC treatment was successful in the treatment of CRP, including those in whom other therapies had previously failed, and resulted in a decreased number of treatments compared with other published studies. The benefits were offset by an increased incidence of short-term complications but no increase in long-term complications.