The efficacy of octreotide in the therapy of acute radiation-induced diarrhea: a randomized controlled study

Racecadotril Versus Loperamide in Acute Radiation Enteritis: A Randomized, Double-Masked, Phase 3, Noninferiority Trial

PURPOSE

There is currently no gold standard for the management of acute radiation enteritis. We compared the efficacy and safety of Racecadotril, an anti-hypersecretory drug, versus Loperamide, an anti-motility agent, in acute radiation enteritis.

METHODS AND MATERIALS

We conducted a randomized, double-masked, non-inferiority trial at a single research institute. Patients receiving curative radiation for pelvic malignancies, who developed grade 2 or 3 diarrhea (as per Common Terminology Criteria for Adverse Events, v 4.0) were included in the study. Patients in the intervention arm received Racecadotril and placebo. Patients in the control arm received Loperamide and placebo. The primary outcome was the resolution of diarrhea, 48 hours after the start of treatment.

RESULTS

162 patients were randomized between 2019 and 2022. On intention-to-treat analysis, 68/81 patients, 84%, (95% CI, 74.1%-91.2%) in the Racecadotril arm and 70/81, 86.4%, (95% CI, 77.0%-93.0%) in the Loperamide arm improved from grade 2 or 3 diarrhea to grade 1 or 0, (P= .66, χ2 test). The difference in proportion was 2.4% (95% CI: -8.5% to 13.4%). Since the upper boundary of the 95% CI crossed our non-inferiority margin of 10% (13.4%) we could not prove the non-inferiority of Racecadotril over Loperamide. Rebound constipation was more in the Loperamide arm compared to Racecadotril (17.3% vs 6.2%; P = .028) CONCLUSIONS: The non-inferiority of Racecadotril to Loperamide in acute radiation enteritis could not be demonstrated. However, Racecadotril can be the preferred drug of choice in acute radiation enteritis because Racecadotril does not affect bowel motility, achieved a high clinical success rate similar to that of Loperamide, and was associated with lesser side effects.

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.

Protective effects of Brownea grandiceps (Jacq.) against ϒ-radiation-induced enteritis in rats in relation to its secondary metabolome fingerprint

Radiation enteritis is the most common complication of radiotherapy in patients with pelvic malignancies. Thus, the radioprotective activity of the total hydro-alcoholic extract (BGE) and the ethyl acetate soluble fraction (EAF) of Brownea grandiceps leaves was evaluated against ϒ-radiation-induced enteritis in rats. (BGE) and (EAF) were characterized using HPLC-PDA-ESI-MS/MS analysis. The total phenolic and flavonoid contents were also quantified. In vivo administration of (BGE) (400 mg/kg) and (EAF) (200 & 400 mg/kg) prevented intestinal injury and maintained the mucosal integrity of irradiated rats through increasing villi length and promoting crypt regeneration. Also, (EAF) showed more potent antioxidant activity than (BGE) through reduction of MDA level and enhancement of GSH content and catalase enzyme activity. (BGE) and (EAF) down-regulated intestinal NF-κB expression leading to diminished expression of downstream inflammatory cytokine TNF-α. Moreover, (EAF) markedly reduced the expression of profibrotic marker TGF-β1. Seventy-nine compounds were tentatively identified, including flavonoids, proanthocyanidins, polar lipids and phenolic acids. (EAF) showed significantly higher total phenolic and flavonoid contents, as compared to (BGE). Results revealed remarkable radioprotective activity of (BGE) and (EAF), with significantly higher activity for (EAF). The chemical constituents of (BGE) and (EAF) strongly supported their radioprotective activity. To the best of our knowledge, the present study describes for the first time the radioprotective activity of B. grandiceps leaves in relation to its secondary metabolome fingerprint; emphasizing the great promise of B. grandiceps leaves, especially (EAF), to be used as natural radio-protective agent.

Radiation therapy-associated toxicity: Etiology, management, and prevention

Radiation therapy (RT) is a curative treatment for many malignancies and provides effective palliation in patients with tumor-related symptoms. However, the biophysical effects of RT are not specific to tumor cells and may produce toxicity due to exposure of surrounding organs and tissues. In this article, the authors review the clinical context, pathophysiology, risk factors, presentation, and management of RT side effects in each human organ system. Ionizing radiation works by producing DNA damage leading to tumor death, but effects on normal tissue may result in acute and/or late toxicity. The manifestation of toxicity depends on both cellular characteristics and affected organs' anatomy and physiology. There is usually a direct relationship between the radiation dose and volume to normal tissues and the risk of toxicity, which has led to guidelines and recommended dose limits for most tissues. Side effects are multifactorial, with contributions from baseline patient characteristics and other oncologic treatments. Technological advances in recent decades have decreased RT toxicity by dramatically improving the ability to deliver RT that maximizes tumor dose and minimizes organ dose. Thus the study of RT-associated toxicity is a complex, core component of radiation oncology training that continues to evolve alongside advances in cancer management. Because RT is used in up to one-half of all patients with cancer, an understanding of its acute and late effects in different organ systems is clinically pertinent to both oncologists and nononcologists.

A phase 2 trial of the somatostatin analog pasireotide to prevent GI toxicity and acute GVHD in allogeneic hematopoietic stem cell transplant

Background

Allogeneic hematopoietic stem cell transplantation (HCT) is an often curative intent treatment, however it is associated with significant gastrointestinal (GI) toxicity and treatment related mortality. Graft-versus-host disease is a significant contributor to transplant-related mortality. We performed a phase 2 trial of the somatostatin analog pasireotide to prevent gastrointestinal toxicity and GVHD after myeloablative allogeneic HCT.

Methods

Patients received 0.9mg pasireotide every 12 hours from the day prior to conditioning through day +4 after HCT (or a maximum of 14 days). The primary outcomes were grade 3–4 gastrointestinal toxicity through day 30 and acute GVHD. Secondary outcomes were chronic GVHD, overall survival and relapse free survival at one year. Stool and blood samples were collected from before and after HCT for analyses of stool microbiome, local inflammatory markers, and systemic inflammatory and metabolic markers. Results were compared with matched controls.

Results

Twenty-six patients received pasireotide and were compared to 52 matched contemporaneous controls using a 1–2 match. Grade 3–4 GI toxicity occurred in 21 (81%) patients who received pasireotide and 35 (67%) controls (p = 0.33). Acute GVHD occurred in 15 (58%) patients in the pasireotide group and 28 (54%) controls (p = 0.94). Chronic GVHD occurred in 16 patients in the pasireotide group (64%) versus 22 patients in the control group (42%) (p = 0.12). Overall survival at 1 year in the pasireotide group was 63% (95% CI: 47%,86%) versus 82% (95% CI: 72%, 93%) in controls (log-rank p = 0.006). Relapse-free survival rate at one year was 40% (95% CI: 25%, 65%) in the pasireotide group versus 78% (95% CI: 68%, 91%) in controls (log-rank p = 0.002). After controlling for the effect of relevant covariates, patients in the pasireotide group had attenuated post-HCT loss of microbial diversity. Analysis of systemic inflammatory markers and metabolomics demonstrated feasibility of such analyses in patients undergoing allogeneic HCT. Baseline level and pre-to-post transplant changes in several inflammatory markers (including MIP1a, MIP1b, TNFa, IL8Pro, and IL6) correlated with likelihood of survival.

Conclusions

Pasireotide did not prevent gastrointestinal toxicity or acute GVHD compared to contemporaneous controls. Pasireotide was associated with numerically higher chronic GVHD and significantly decreased OS and RFS compared to contemporaneous controls. Pasireotide may provide a locally protective effect in the stool microbiome and in local inflammation as measured by stool calprotectin, stool beta-defensin, and stool diversity index.

Coenzyme Q10 attenuates inflammation and fibrosis implicated in radiation enteropathy through suppression of NF-kB/TGF-β/MMP-9 pathways

Radiation enteropathy is one the most common clinical issue for patients receiving radiotherapy for abdominal/pelvic tumors which severely affect the quality of life of cancer patients due to dysplastic lesions (ischemia, ulcer, or fibrosis) that aggravate the radiation damage. Herein, this study demonstrated the prophylactic role of coenzyme Q10 (CoQ10), a powerful antioxidant, against radiotherapy-induced gastrointestinal injury. Male Sprague Dawley rats were divided into four groups: group 1 was defined as control, and group 2 was the irradiated group. Group 3 and 4 were CoQ10 control and radiation plus CoQ10 groups, respectively. CoQ10 (10 mg/kg) was orally administered for 10 days before 10 Gy whole-body radiation and was continued for 4 days post-irradiation. CoQ10 administration protected rats delivered a lethal dose of ϒ-radiation from changes in crypt-villus structures and promoted regeneration of the intestinal epithelium. CoQ10 attenuated radiation-induced oxidative stress by decreasing lipid peroxidation and increasing the antioxidant enzyme catalase activity and reduced glutathione level. CoQ10 also counteracts inflammatory response mediated after radiation exposure through downregulating intestinal NF-ĸB expression which subsequently decreased the level of inflammatory cytokine IL-6 and the expression of COX-2. Radiation-induced intestinal fibrosis confirmed via Masson's trichrome staining occurred through upregulating transforming growth factor (TGF)-β1 and matrix metalloproteinase (MMP)-9 expression, while CoQ10 administration significantly diminishes these effects which further confirmed the anti-fibrotic property of CoQ10. Therefore, CoQ10 is a promising radioprotector that could prevent intestinal complications and enhance the therapeutic ratio of radiotherapy in patients with pelvic tumors through suppressing the NF-kB/TGF-β1/MMP-9 signaling pathway.

Radioprotection and Radiomitigation: From the Bench to Clinical Practice

The development of protective agents against harmful radiations has been a subject of investigation for decades. However, effective (ideal) radioprotectors and radiomitigators remain an unsolved problem. Because ionizing radiation-induced cellular damage is primarily attributed to free radicals, radical scavengers are promising as potential radioprotectors. Early development of such agents focused on thiol synthetic compounds, e.g., amifostine (2-(3-aminopropylamino) ethylsulfanylphosphonic acid), approved as a radioprotector by the Food and Drug Administration (FDA, USA) but for limited clinical indications and not for nonclinical uses. To date, no new chemical entity has been approved by the FDA as a radiation countermeasure for acute radiation syndrome (ARS). All FDA-approved radiation countermeasures (filgrastim, a recombinant DNA form of the naturally occurring granulocyte colony-stimulating factor, G-CSF; pegfilgrastim, a PEGylated form of the recombinant human G-CSF; sargramostim, a recombinant granulocyte macrophage colony-stimulating factor, GM-CSF) are classified as radiomitigators. No radioprotector that can be administered prior to exposure has been approved for ARS. This differentiates radioprotectors (reduce direct damage caused by radiation) and radiomitigators (minimize toxicity even after radiation has been delivered). Molecules under development with the aim of reaching clinical practice and other nonclinical applications are discussed. Assays to evaluate the biological effects of ionizing radiations are also analyzed.

Efficacy of herbal medicine TJ-14 for acute radiation-induced enteritis: a multi-institutional prospective Phase II trial

The purpose of this multi-institutional Phase II trial study was to prospectively investigate the efficacy of the herbal medicine TJ-14 for acute radiation-induced enteritis (ARE). TJ-14 was administered orally as a first-line treatment for ARE. The primary end point was efficacy at 1 week. The secondary end points were: (i) the efficacy of TJ-14 at 2 and 3 weeks after its administration, (ii) the quality of life score (FACT-G) at 1, 2 and 3 weeks after its administration, and (iii) adverse events. If the efficacy of TJ-14 was observed in eight patients or fewer, its efficacy was rejected. Results: Forty patients receiving pelvic radiotherapy were enrolled. Of these, 22 developed ARE and received TJ-14. Among these, 19 had cervical cancer and 9 received chemoradiotherapy. TJ-14 efficacy was shown in 19 out of the 22 patients (86%). Stool frequency per day at 1 week significantly decreased (mean ± SD: 4.9 ± 2.1 vs 3.7 ± 1.9, P = 0.02). This effect continued at 2 (2.2 ± 1.4, P = 0.004) and 3 weeks (2.1 ± 0.9, P = 0.05). Thirteen out of the 22 patients (59%) continued TJ-14 until the end of radiotherapy. FACT-G score deterioration was not observed after the administration of TJ-14. Grade 1 hypokalemia was observed in 4 patients, and Grade 1 constipation in 3. We concluded that TJ-14 is sufficiently promising to be examined in a Phase III trial. A randomized controlled trial is currently being planned.

Interventions to reduce acute and late adverse gastrointestinal effects of pelvic radiotherapy for primary pelvic cancers

BACKGROUND

An increasing number of people survive cancer but a significant proportion have gastrointestinal side effects as a result of radiotherapy (RT), which impairs their quality of life (QoL).

OBJECTIVES

To determine which prophylactic interventions reduce the incidence, severity or both of adverse gastrointestinal effects among adults receiving radiotherapy to treat primary pelvic cancers.

SEARCH METHODS

We conducted searches of CENTRAL, MEDLINE, and Embase in September 2016 and updated them on 2 November 2017. We also searched clinical trial registries.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of interventions to prevent adverse gastrointestinal effects of pelvic radiotherapy among adults receiving radiotherapy to treat primary pelvic cancers, including radiotherapy techniques, other aspects of radiotherapy delivery, pharmacological interventions and non-pharmacological interventions. Studies needed a sample size of 20 or more participants and needed to evaluate gastrointestinal toxicity outcomes. We excluded studies that evaluated dosimetric parameters only. We also excluded trials of interventions to treat acute gastrointestinal symptoms, trials of altered fractionation and dose escalation schedules, and trials of pre- versus postoperative radiotherapy regimens, to restrict the vast scope of the review.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. We used the random-effects statistical model for all meta-analyses, and the GRADE system to rate the certainty of the evidence.

MAIN RESULTS

We included 92 RCTs involving more than 10,000 men and women undergoing pelvic radiotherapy. Trials involved 44 different interventions, including radiotherapy techniques (11 trials, 4 interventions/comparisons), other aspects of radiotherapy delivery (14 trials, 10 interventions), pharmacological interventions (38 trials, 16 interventions), and non-pharmacological interventions (29 trials, 13 interventions). Most studies (79/92) had design limitations. Thirteen studies had a low risk of bias, 50 studies had an unclear risk of bias and 29 studies had a high risk of bias. Main findings include the following:Radiotherapy techniques: Intensity-modulated radiotherapy (IMRT) versus 3D conformal RT (3DCRT) may reduce acute (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.26 to 0.88; participants = 444; studies = 4; I2 = 77%; low-certainty evidence) and late gastrointestinal (GI) toxicity grade 2+ (RR 0.37, 95% CI 0.21 to 0.65; participants = 332; studies = 2; I2 = 0%; low-certainty evidence). Conformal RT (3DCRT or IMRT) versus conventional RT reduces acute GI toxicity grade 2+ (RR 0.57, 95% CI 0.40 to 0.82; participants = 307; studies = 2; I2 = 0%; high-certainty evidence) and probably leads to less late GI toxicity grade 2+ (RR 0.49, 95% CI 0.22 to 1.09; participants = 517; studies = 3; I2 = 44%; moderate-certainty evidence). When brachytherapy (BT) is used instead of external beam radiotherapy (EBRT) in early endometrial cancer, evidence indicates that it reduces acute GI toxicity (grade 2+) (RR 0.02, 95% CI 0.00 to 0.18; participants = 423; studies = 1; high-certainty evidence).Other aspects of radiotherapy delivery: There is probably little or no difference in acute GI toxicity grade 2+ with reduced radiation dose volume (RR 1.21, 95% CI 0.81 to 1.81; participants = 211; studies = 1; moderate-certainty evidence) and maybe no difference in late GI toxicity grade 2+ (RR 1.02, 95% CI 0.15 to 6.97; participants = 107; studies = 1; low-certainty evidence). Evening delivery of RT may reduce acute GI toxicity (diarrhoea) grade 2+ during RT compared with morning delivery of RT (RR 0.51, 95% CI 0.34 to 0.76; participants = 294; studies = 2; I2 = 0%; low-certainty evidence). There may be no difference in acute (RR 2.22, 95% CI 0.62 to 7.93, participants = 110; studies = 1) and late GI toxicity grade 2+ (RR 0.44, 95% CI 0.12 to 1.65; participants = 81; studies = 1) between a bladder volume preparation of 1080 mls and that of 540 mls (low-certainty evidence). Low-certainty evidence on balloon and hydrogel spacers suggests that these interventions for prostate cancer RT may make little or no difference to GI outcomes.Pharmacological interventions: Evidence for any beneficial effects of aminosalicylates, sucralfate, amifostine, corticosteroid enemas, bile acid sequestrants, famotidine and selenium is of a low or very low certainty. However, evidence on certain aminosalicylates (mesalazine, olsalazine), misoprostol suppositories, oral magnesium oxide and octreotide injections suggests that these agents may worsen GI symptoms, such as diarrhoea or rectal bleeding.Non-pharmacological interventions: Low-certainty evidence suggests that protein supplements (RR 0.23, 95% CI 0.07 to 0.74; participants = 74; studies = 1), dietary counselling (RR 0.04, 95% CI 0.00 to 0.60; participants = 74; studies = 1) and probiotics (RR 0.43, 95% CI 0.22 to 0.82; participants = 923; studies = 5; I2 = 91%) may reduce acute RT-related diarrhoea (grade 2+). Dietary counselling may also reduce diarrhoeal symptoms in the long term (at five years, RR 0.05, 95% CI 0.00 to 0.78; participants = 61; studies = 1). Low-certainty evidence from one study (108 participants) suggests that a high-fibre diet may have a beneficial effect on GI symptoms (mean difference (MD) 6.10, 95% CI 1.71 to 10.49) and quality of life (MD 20.50, 95% CI 9.97 to 31.03) at one year. High-certainty evidence indicates that glutamine supplements do not prevent RT-induced diarrhoea. Evidence on various other non-pharmacological interventions, such as green tea tablets, is lacking.Quality of life was rarely and inconsistently reported across included studies, and the available data were seldom adequate for meta-analysis.

AUTHORS' CONCLUSIONS

Conformal radiotherapy techniques are an improvement on older radiotherapy techniques. IMRT may be better than 3DCRT in terms of GI toxicity, but the evidence to support this is uncertain. There is no high-quality evidence to support the use of any other prophylactic intervention evaluated. However, evidence on some potential interventions shows that they probably have no role to play in reducing RT-related GI toxicity. More RCTs are needed for interventions with limited evidence suggesting potential benefits.

Role of drugs in the prevention and amelioration of radiation induced toxic effects

As the use of radiation technology for nuclear warfare or for the benefits of mankind (e.g. in radiotherapy or radio-diagnosis) is increasing tremendously, the risk of associated side effects is becoming a cause of concern. These effects, ranging from nausea/vomiting to death, may result from accidental or deliberate exposure and begin in seconds. Through this review paper, efforts have been done to critically review different compounds which have been investigated as radioprotectors and radiation mitigators. Radioprotectors are compounds which are administered just before or at the time of irradiation so as to minimize the radiation induced damage to normal tissues. And radiation mitigators are the compounds which can even minimize or ameliorate post irradiaion-toxicity provided they are administered before the onset of toxic symptoms. A variety of agents have been investigated for their preventive and ameliorative potential against radiation induced toxic effects. This review article has focused on various aspects of the promising representative agents belonging to different classes of radioprotectors and mitigators. Many compounds have shown promising results, but till date only amifostine and palifermin are clinically approved by FDA. To fill this void in pharmacological armamentarium, focus should be shifted towards novel approaches.

Randomized Phase III Trial Exploring the Use of Long-Acting Release Octreotide in the Prevention of Chemotherapy-Induced Diarrhea in Patients With Colorectal Cancer: The LARCID Trial

Purpose

Chemotherapy-induced diarrhea (CID) is a relatively common adverse event in the treatment of patients with colorectal cancer. The LAR for Chemotherapy-Induced Diarrhea (LARCID) trial evaluated the efficacy and safety of long-acting release octreotide (octreotide LAR) for the prevention of CID in this population.

Patients and Methods

Patients with colorectal cancer starting adjuvant or first-line treatment with a chemotherapy combination containing fluorouracil, capecitabine, and/or irinotecan were randomly assigned to receive octreotide LAR 30 mg intramuscularly every 4 weeks (experimental arm) or the physician's treatment of choice in case of diarrhea (control arm).

Results

A total of 139 patients were randomly assigned, most of whom received fluorouracil- and oxaliplatin-containing chemotherapy regimens. The rate of diarrhea was 76.1% in the experimental group (n = 68) and 78.9% in the control group (n = 71). Treatment with octreotide LAR did not prevent or reduce the severity of CID. Treatment choices for diarrhea management included loperamide in the majority of patients. No benefit from octreotide LAR was identified in terms of need for diarrhea treatment, opioids, or intravenous hydration or in the rate of hospitalization or quality of life.

Conclusion

This study could not prove the efficacy of octreotide LAR in the prevention of CID.

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.

Colorectal cancer emergencies

INTRODUCTION

Colorectal cancer (CRC) is a common type of malignancy encountered in the United States. A significant proportion of patients with CRC will seek emergency medical care during the course of their illness and treatment.

BACKGROUND

Emergent presentations can be the result of either local tumor invasion, regional progression, or therapeutic techniques. Specific complications of CRC which present emergently include rectal bleeding, abdominal pain, and bowel obstruction. Less common issues encountered include malignant ascites, neutropenic enterocolitis, and radiation enteropathy.

CONCLUSION

The care of CRC patients in the setting of an acute severe illness typically requires the joint efforts of the emergency medical team in consultation with surgical, medical, and radiation oncology. A high degree of suspicion for the typical and atypical complications of CRC is important for all clinicians who are responsible for the care of these patients.

Pharmaceutical drugs supporting regeneration of small-intestinal mucosa severely damaged by ionizing radiation in mice

Accidental exposure of the abdomen to high-dose radiation leads to severe consequences initiated by disruption of the mucosa in the small intestine. Therapeutic options are limited, even though various treatments have been investigated, particularly in the field of regenerative therapy. In order to identify readily available treatment methods, we included several current pharmaceutical drugs, for which the clinical trials have already been completed, in tests on mice that had undergone severe mucosal damage by radiation. The drugs were injected into mice 24 h after exposure to 15.7 Gy X-rays. The effects of the drugs on the damaged mucosa of the small intestine were evaluated using early regeneration indices [the expression of c-myb mRNA, and proliferation of epithelial cells in the form of microcolonies (MCs) by Days 4 and 5 post-irradiation] and the survival rate of the mice. Enhancement of mucosal regeneration at Day 4 (c-myb: P < 0.01, MC: P < 0.05) and improvement of the survival rate (P < 0.05) were observed when a clinical dose of gonadotropin, a stimulator of androgen, was injected. Similarly, a clinical dose of thiamazole (which prevents secretion of thyroid hormone) stimulated mucosal growth by Day 5 (c-myb: P < 0.01, MC: P < 0.05) and also improved the survival rate (P < 0.05). The nonclinical drugs histamine and high-dose octreotide (a growth hormone antagonist) also gave significant survival-enhancing benefits (P < 0.01 and P < 0.05, respectively). These results can be used to construct therapeutic programs and applied in various experimental studies to control the regeneration of damaged mucosa.

Role of octreotide in post chemotherapy and/or radiotherapy diarrhea: prophylaxis or therapy?

AIM

The clinical efficacy of octreotide in controlling chemoradiotherapy-induced diarrhea remains controversial. We conducted a meta-analysis of randomized controlled trials (RCT) comparing octreotide with placebo in the prevention or therapy of chemoradiotherapy-induced diarrhea.

METHODS

A computerized literature search of Medline, EMBASE, Cochrane Library and BIOSIS databases were performed for RCT comparing the use of octreotide versus placebo in the management of patients with chemoradiotherapy-induced diarrhea. The main outcome measure was the response of the diarrhea.

RESULTS

We included eight RCT comprising 572 patients. We found octreotide was significantly effective compared with the placebo (OR, 4.9; 95%, 1.58-15.2).The overall effect of octreotide was 69% (204/294), while that of placebo was 54% (149/278). When divided into prophylactic and therapeutic subgroups, the prophylactic subgroup had an OR of 2.11 (95% CI, 0.51-2.89) for chemoradiotherapy-induced diarrhea and the therapeutic subgroup had an OR of 7.30 (95% CI, 4.09-13.04).

CONCLUSION

In chemoradiotherapy-induced diarrhea, octreotide is best used as a therapeutic rather than a prophylactic agent against diarrhea.

Novel drugs to ameliorate gastrointestinal normal tissue radiation toxicity in clinical practice: what is emerging from the laboratory?

PURPOSE OF REVIEW

To give an overview of promising novel agents under development for the prevention and reduction of gastrointestinal radiation injury.

RECENT FINDINGS

Currently, several novel agents are being tested as drugs to prevent or reduce gastrointestinal radiation injury. These drugs may not only prevent injury, but also mitigate toxicity, that is, reduce injury after radiation exposure has occurred. Promising novel agents include the somatostatin analogue SOM230, growth factors, agents acting on the toll-like receptor 5 pathway, endothelial protectants, and the vitamin E analogue γ-tocotrienol.

SUMMARY

Gastrointestinal radiation injury is the most important dose-limiting factor during radiotherapy of the abdomen or pelvis. It may severely affect the quality of life both during radiotherapy treatment and in cancer survivors. To date, there are no agents that can prevent or reduce intestinal radiation injury. Hence, there is an urgent need for the development of novel drugs to ameliorate intestinal toxicity during and after radiotherapy. This review summarizes the several agents that have been shown to reduce intestinal radiation injury in animals. Further research is needed to investigate their safety and efficacy in patients receiving radiotherapy for abdominal or pelvic tumours.

ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context

This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

Literature review and global consensus on management of acute radiation syndrome affecting nonhematopoietic organ systems

OBJECTIVES

The World Health Organization convened a panel of experts to rank the evidence for medical countermeasures for management of acute radiation syndrome (ARS) in a hypothetical scenario involving the hospitalization of 100 to 200 victims. The goal of this panel was to achieve consensus on optimal management of ARS affecting nonhematopoietic organ systems based upon evidence in the published literature.

METHODS

English-language articles were identified in MEDLINE and PubMed. Reference lists of retrieved articles were distributed to conferees in advance of and updated during the meeting. Published case series and case reports of ARS, publications of randomized controlled trials of relevant interventions used to treat nonirradiated individuals, reports of studies in irradiated animals, and prior recommendations of subject matter experts were selected. Studies were extracted using the Grading of Recommendations Assessment Development and Evaluation system. In cases in which data were limited or incomplete, a narrative review of the observations was made.

RESULTS

No randomized controlled trials of medical countermeasures have been completed for individuals with ARS. Reports of countermeasures were often incompletely described, making it necessary to rely on data generated in nonirradiated humans and in experimental animals. A strong recommendation is made for the administration of a serotonin-receptor antagonist prophylactically when the suspected exposure is >2 Gy and topical steroids, antibiotics, and antihistamines for radiation burns, ulcers, or blisters; excision and grafting of radiation ulcers or necrosis with intractable pain; provision of supportive care to individuals with neurovascular syndrome; and administration of electrolyte replacement therapy and sedatives to individuals with significant burns, hypovolemia, and/or shock. A strong recommendation is made against the use of systemic steroids in the absence of a specific indication. A weak recommendation is made for the use of fluoroquinolones, bowel decontamination, loperamide, and enteral nutrition, and for selective oropharyngeal/digestive decontamination, blood glucose maintenance, and stress ulcer prophylaxis in critically ill patients.

CONCLUSIONS

High-quality studies of therapeutic interventions in humans exposed to nontherapeutic radiation are not available, and because of ethical concerns regarding the conduct of controlled studies in humans, such studies are unlikely to emerge in the near future.

Preclinical evaluation of Som230 as a radiation mitigator in a mouse model: postexposure time window and mechanisms of action

The somatostatin analog SOM230 has potent radioprophylactic and radiation mitigating properties that are unrelated to cytoprotection but appear to be due to suppression of secretion of pancreatic enzymes into the intestinal lumen. To determine the maximal postirradiation time window for administration, male CD2F1 mice were exposed to 8.5-11 Gy total-body radiation; SOM230 (0.5, 2 or 5 mg/kg) or vehicle was given by twice daily subcutaneous injections for 14 days, beginning 24-72 h after irradiation, and 30-day animal survival was recorded. The contribution of the gut to systemic cytokine levels was estimated by analyzing plasma samples obtained simultaneously from the portal vein and carotid artery. The effect of SOM230 on cell trypsin secretion was assessed in vitro and intestinal proteolytic activity was measured in vivo. SOM230 was associated with a 40-60% absolute improvement in overall postirradiation survival when treatment was started 48 h after irradiation and even exhibited a statistically significant survival benefit when started at 72 h. SOM230 ameliorated the radiation-induced decrease in chemokine (C-X-C motif) ligand 9 (CXCL9). SOM230 inhibited pancreatic acinar cell trypsin secretion in vitro in a dose-dependent fashion and reduced intraluminal and intestinal tissue proteolytic activity in vivo. SOM230 is an excellent radiation mitigator with a postirradiation time window in excess of 48 h. The mechanism likely involves preservation of intestinal barrier function due to decreased secretion of pancreatic enzymes into the bowel lumen.

Protective effects of melatonin and octreotide against radiation-induced intestinal injury

PURPOSE

To compare the protective effects of the potent antioxidants, melatonin and octreotide, against radiation-induced intestinal injury.

METHODS

A total of 42 male 3-month-old Swiss albino mice (40 ± 10 g) were matched according to body weight and randomly assigned to one of six groups: control; radiation treatment (RT) only; melatonin only (15 mg/kg, i.p.); melatonin + RT; octreotide only (50 μg/kg i.p.); and octreotide + RT. Intestinal damage was induced by exposure to a single whole-body radiation dose of 8 Gy. All mice tolerated the experimental interventions, and no deaths were observed.

RESULTS

Irradiation induced architectural disorganization, including inflammatory mononuclear cell infiltration, villitis, and desquamation with eosinophilic necrosis, and diminished mucosal thickness, crypt height, and villous height. In the melatonin + RT and octreotide + RT groups, the villous pattern was well preserved; desquamation at villous tips and edema was prominent, but necrosis was absent. The radiation-induced decrease in mucosal thickness was significantly reduced by pretreatment with melatonin (p < 0.001) or octreotide (p = 0.01), although the protective effect was significantly greater for melatonin (p = 0.04). Pretreatment with melatonin also preserved villous height (p = 0.009) and crypt height (p = 0.03); although a similar trend was observed for pre-irradiation octreotide, the differences were not significant.

CONCLUSIONS

Melatonin and octreotide potently protected against radiation-induced intestinal injury in mice, but melatonin was significantly more effective in preserving the histological structure of the intestines, a finding that warrants confirmation in clinical studies.

Pharmacological management of diarrhea

According to the World Health Organization, there are approximately 2 billion annual cases of diarrhea worldwide. Diarrhea is the leading cause of death in children younger than 5 years and kills 1.5 million children each year. It is especially prevalent in the developing world, where mortality is related to dehydration, electrolyte disturbance, and the resultant acidosis, and in 2001, it accounted for 1.78 million deaths (3.7% of total deaths) in low- and middle-income countries. However, diarrhea is also a common problem in the developed world, with 211 million to 375 million episodes of infectious diarrheal illnesses in the United States annually, resulting in 73 million physician consultations, 1.8 million hospitalizations, and 3100 deaths. Furthermore, 4% to 5% of the Western population suffers from chronic diarrhea. Given the high prevalence of diarrhea, research has been directed at learning more about the cellular mechanisms underlying diarrheal illnesses in order to develop new medications directed at novel cellular targets. These cellular mechanisms and targets are discussed in this article.

Octreotide acetate in prevention of chemoradiation-induced diarrhea in anorectal cancer: randomized RTOG trial 0315

BACKGROUND

In anorectal cancer patients, an acute side effect of chemoradiotherapy is gastrointestinal toxicity, which often impedes treatment delivery. Based on previous trials, octreotide acetate is widely recommended for the control of chemotherapy-induced diarrhea. However, the effectiveness of octreotide in preventing or controlling radiation- and chemoradiation-induced diarrhea is not known.

METHODS

A randomized, double-blinded, placebo-controlled trial was designed to determine the efficacy of long-acting octreotide acetate (LAO) in preventing the onset of acute diarrhea in patients undergoing chemoradiation therapy for rectal or anal cancer. Between 4 and 7 days before the start of radiation therapy, patients received a 30-mg dose of LAO (109 patients) or placebo (106 patients) via intramuscular injection. A second dose was given on day 22 (+/-3 days) of radiation treatment. A total of 215 patients were included in the final analysis. The primary endpoint was the incidence of grade 2-4 acute diarrhea; secondary endpoints included treatment compliance, medical resource utilization, patient-reported bowel function, and quality of life (QoL). Statistical tests were one- or two-sided, as specified.

RESULTS

After a median follow-up time of 9.64 months, incidence rates of grades 2-4 acute diarrhea were similar in both groups (49% placebo vs 44% LAO; P = .21). No statistically significant treatment differences in chemotherapy or radiation delivery, medical resource utilization, patient-reported bowel function, or QoL were observed.

CONCLUSION

In this study, the prophylactic use of LAO did not prevent the incidence or reduce the severity of diarrhea and had no notable impact on patient-reported bowel function or QoL.

Prevention and management of chemotherapy-induced diarrhea in patients with colorectal cancer: a consensus statement by the Canadian Working Group on Chemotherapy-Induced Diarrhea

Chemotherapy-induced diarrhea (cid) is a common side effect of cancer treatment and can cause significant morbidity and mortality. Diarrhea is frequently severe enough to require a dose reduction of, a delay in, or a discontinuation of chemotherapy. Diarrhea-associated mortality has been reported to be as high as 3.5% in clinical trials of irinotecan and bolus 5-fluorouracil in colorectal cancer. The frequency of cid and its impact on patient management are frequently under-recognized in clinical practice.A Canadian working group, consisting of medical oncologists and an oncology pharmacist, was formed in 2001 to review the optimal approach to managing cid and to identify and implement new areas of research. The recommendations that follow are the result of the group's work.Acute medical management of cid includes loperamide or diphenoxylate as first-line agents. Subcutaneous octreotide is recommended for intractable grade 2 diarrhea and may be considered for grade 1 cid that does not resolve with high-dose loperamide. Hospitalization is recommended for patients with grades 3 and 4 cid; in-hospital care includes rehydration, antibiotic therapy, and octreotide.A chemotherapy dose reduction is generally advised for patients who have experienced grade 3 or 4 diarrhea in a previous chemotherapy cycle. If a dose reduction is not desired, prophylaxis with intramuscular long-acting release octreotide may be considered.The foregoing recommendations are based on expert opinion and require validation in prospective clinical trials.

The somatostatin analog SOM230 (pasireotide) ameliorates injury of the intestinal mucosa and increases survival after total-body irradiation by inhibiting exocrine pancreatic secretion

Somatostatin analogs ameliorate intestinal injury after localized irradiation. This study investigated whether SOM230, a novel, metabolically stable analog with broad receptor affinity, reduces intestinal injury and lethality in mice exposed to total-body irradiation (TBI). Male CD2F1 mice were exposed to 7-15 Gy TBI. Twice-daily administration of SOM230 (1, 4 or 10 mg/kg per day) or vehicle was started either 2 days before or 4 h after TBI and continued for either 14 or 21 days. Parameters of intestinal and hematopoietic radiation injury, bacterial translocation, and circulating cytokine levels were assessed. Animal survival was monitored for up to 30 days. SOM230 increased survival (P < 0.001) and prolonged survival time (P < 0.001) whether administration was initiated before or after TBI. There was no benefit from administration for 21 compared to 14 days. The survival benefit of SOM230 was completely reversed by co-administration of pancreatic enzymes (P = 0.009). Consistent with the presumed non-cytoprotective mechanism of action, SOM230 did not influence hematopoietic injury or intestinal crypt lethality. However, SOM230 preserved mucosal surface area (P < 0.001) and reduced bacterial translocation in a dose-dependent manner (P < 0.001). Circulating IL-12 levels were reduced in SOM230-treated mice (P = 0.007). No toxicity from SOM230 was observed. SOM230 enhances animal survival whether administration begins before or after TBI; i.e., it is effective both as a protector and as a mitigator. The mechanism likely involves reduction of intraluminal pancreatic enzymes. Because of its efficacy and favorable safety profile, SOM230 is a promising countermeasure against radiation and should undergo further development.

Recent advances in the management of radiation colitis

Radiation colitis, an insidious, progressive disease of increasing frequency, develops 6 mo to 5 years after regional radiotherapy for malignancy, owing to the deleterious effects of the latter on the colon and the small intestine. When dealing with radiation colitis and its complications, the most conservative modality should be employed because the areas of intestinal injury do not tend to heal. Acute radiation colitis is mostly self-limited, and usually, only supportive management is required. Chronic radiation colitis, a poorly predictable progressive disease, is considered as a precancerous lesion; radiation-associated malignancy has a tendency to be diagnosed at an advanced stage and to bear a dismal prognosis. Therefore, management of chronic radiation colitis remains a major challenge owing to the progressive evolution of the disease, including development of fibrosis, endarteritis, edema, fragility, perforation, partial obstruction, and cancer. Patients are commonly managed conservatively. Surgical intervention is difficult to perform because of the extension of fibrosis and alterations in the gut and mesentery, and should be reserved for intestinal obstruction, perforation, fistulas, and severe bleeding. Owing to the difficulty in managing the complications of acute and chronic radiation colitis, particular attention should be focused onto the prevention strategies. Uncovering the fibrosis mechanisms and the molecular events underlying radiation bowel disease could lead to the introduction of new therapeutic and/or preventive approaches. A variety of novel, mostly experimental, agents have been used mainly as a prophylaxis, and improvements have been made in radiotherapy delivery, including techniques to reduce the amount of exposed intestine in the radiation field, as a critical strategy for prevention.

Radiation damage to the gastrointestinal tract: mechanisms, diagnosis, and management

PURPOSE OF REVIEW

To summarize current knowledge about gastrointestinal radiation toxicity, with emphasis on mechanisms and clinical diagnosis and management.

RECENT FINDINGS

While there has been only modest change in cancer incidence and cancer mortality rates during the past 30 years, the number of cancer survivors has more than doubled. Moreover, the recognition of uncomplicated cancer cure as the ultimate goal in oncology has intensified efforts to prevent, diagnose, and manage side effects of radiation therapy. These efforts have been facilitated by recent insight into the underlying pathophysiology.

SUMMARY

The risk of injury to the intestine is dose limiting during abdominal and pelvic radiation therapy. Delayed bowel toxicity is difficult to manage and adversely impacts the quality of life of cancer survivors. More than 200,000 patients per year receive abdominal or pelvic radiation therapy, and the estimated number of cancer survivors with postradiation intestinal dysfunction is 1.5-2 million. Worthwhile progress towards reducing toxicity of radiation therapy has been made by dose-sculpting treatment techniques. Approaches derived from an improved understanding of the pathophysiology of bowel injury, however, will result in further advances. This article discusses the mechanisms of radiation-induced bowel toxicity and reviews current principles in diagnosis and management.

Phase III, double-blind study of depot octreotide versus placebo in the prevention of acute diarrhea in patients receiving pelvic radiation therapy: results of North Central Cancer Treatment Group N00CA

PURPOSE

To assess the effectiveness of depot octreotide for the prevention of diarrhea during pelvic radiation therapy.

PATIENTS AND METHODS

Patients receiving pelvic radiation therapy (planned minimum dose, 45 Gy; 1.7 to 2.1 Gy daily) were eligible for the study. From May 10, 2002, through October 14, 2005, 125 patients were randomly allocated in a double-blind fashion to receive octreotide (100 microg, administered subcutaneously on day 1, followed by depot octreotide, 20 mg, administered intramuscularly on days 2 and 29; n = 62) or to receive a placebo (n = 63).

RESULTS

Grade 0, 1, 2, and 3 diarrhea were observed in 18%, 31%, 31%, and 21% of patients in the octreotide arm, respectively, and in 25%, 32%, 22%, and 21% of patients in the placebo arm, respectively (P = .64). Grade 0, 1, 2, and 3 abdominal cramps were observed in 32%, 45%, 21%, and 2% of patients receiving octreotide, respectively, and in 51%, 24%, 21%, and 5% of patients receiving the placebo, respectively (P = .053). Some patient-reported symptoms were worse in the octreotide group, including nocturnal bowel movements (70% v 45%; P = .004), clustering of bowel movements (90% v 69%; P = .004), and bleeding with bowel movements (57% v 35%; P = .01).

CONCLUSION

As administered in this study, octreotide did not decrease diarrhea during pelvic radiation therapy. Some gastrointestinal symptoms were worse in patients treated with octreotide. Octreotide is not indicated for prevention of diarrhea during pelvic radiation therapy.

Effect of heme oxygenase-1 induction by octreotide on TNBS-induced colitis

BACKGROUND AND AIM

Ulcerative colitis is a chronic inflammatory disease of the colon and rectum. Although the precise etiology of ulcerative colitis remains unknown, it is believed to involve an abnormal host response to endogenous or environmental antigens, genetic factors, and oxidative damage. The aim of the present study was to investigate whether heme oxygenase-1 (HO-1) induction by octreotide could protect against oxidative and inflammatory damage from induced colitis.

METHODS

Rats received octreotide 50 microg/kg per day intraperitoneally for 5 days before 2,4,6 trinitrobenzene sulfonic acid (TNBS) solution administration and for 15 days following TNBS solution administration. Rats were killed on day 21, and colonic malondialdehyde (MDA) levels, glutathione (GSH) levels and HO-1 expression were measured. Nuclear factor (NF)-kappaB and HO-1 expression was evaluated by immunohistochemical examination of the colonic tissue.

RESULTS

Rats with TNBS-induced colitis had significantly increased colonic MDA levels and HO-1 expression in comparison to the control group. Octreotide treatment was associated with increased HO-1 expression and GSH levels, but decreased MDA levels. Histopathological examination revealed that the intestinal mucosal structure was preserved in the octreotide-treated group. In addition, treatment with octreotide significantly increased HO-1 expression and decreased NF-kappaB expression by immunohistochemistry when compared to the TNBS-induced colitis group.

CONCLUSION

Octreotide appears to have protective effects against colonic damage in TNBS-induced colitis. This protective effect is, in part, mediated by modification of the inflammatory response and the induction of HO-1 expression.

Octreotide in the management of chemoradiotherapy-induced diarrhea refractory to loperamide in patients with rectal carcinoma

OBJECTIVE

To evaluate the efficacy of octreotide in the treatment of chemoradiotherapy (CRT)-induced diarrhea (CRTID) refractory to conventional loperamide treatment in this pilot study.

METHODS

Forty-two rectal carcinoma (T(3-4)N(0-2)M(0)) patients with grade 2 or 3 diarrhea refractory to loperamide were enrolled to receive octreotide. Eligible patients were treated with pelvic radiotherapy combined with bolus 5- fluorouracil CRT. Octreotide was administered subcutaneously, 150 microg three times daily, for 5 consecutive days. Only complete resolution of diarrhea was considered as therapeutic success.

RESULTS

Diarrhea mainly occurred in the first 4 weeks of CRT (83.3%) and completely resolved in 34 patients (80.9%) following octreotide administration. Mean time to response was 2.7 days: 27 patients (64%) responded during the first 3 days, and the remaining 7 (17%) on days 4 and 5. No significant side effect was reported. Eight patients (19.1%) with refractory diarrhea were hospitalized for additional treatment. No treatment delay was reported in complete responders, whereas an average 7.7-day delay was observed in refractory patients. Antidiarrheal treatment was administered on an outpatient basis in the response group, whereas refractory patients were hospitalized for an average of 8.8 days.

CONCLUSION

Daily subcutaneous octreotide administration (150 microg t.i.d.) for 5 days is apparently an effective, tolerable treatment modality for concurrent CRTID refractory to loperamide.

Use of probiotics for prevention of radiation-induced diarrhea

AIM: To investigate the efficacy of a high-potency probiotic preparation on prevention of radiation-induced diarrhea in cancer patients.

METHODS: This was a double-blind, placebo-controlled trial. Four hundred and ninety patients who underwent adjuvant postoperative radiation therapy after surgery for sigmoid, rectal, or cervical cancer were assigned to either the high-potency probiotic preparation VSL#3 (one sachet t.i.d.,) or placebo starting from the first day of radiation therapy. Efficacy endpoints were incidence and severity of radiation-induced diarrhea, daily number of bowel movements, and the time from the start of the study to the use of loperamide as rescue medication.

RESULTS: More placebo patients had radiation-induced diarrhea than VSL#3 patients (124 of 239 patients, 51.8%, and 77 of 243 patients, 31.6%; P < 0.001) and more patients given placebo suffered grade 3 or 4 diarrhea compared with VSL#3 recipients (55.4% and 1.4%, P < 0.001). Daily bowel movements were 14.7 ± 6 and 5.1 ± 3 among placebo and VSL#3 recipients (P < 0.05), and the mean time to the use of loperamide was 86 ± 6 h for placebo patients and 122 ± 8 h for VSL#3 patients (P < 0.001).

CONCLUSION: Probiotic lactic acid-producing bacteria are an easy, safe, and feasible approach to protect cancer patients against the risk of radiation-induced diarrhea.

The effect of heme oxygenase-1 induction by octreotide on radiation enteritis

Radiation enteritis occurs as a response to abdominal radiation, which can cause mucosal damage in the gastrointestinal mucosal epithelium. The small intestine is one of the most radiosensitive organs in the abdomen. The present study was undertaken to investigate the effect of octreotide (OCT) administration on heme oxygenase-1 (HO-1) expression of the radiation enteritis model. Rats received 50 mg/kg/day OCT for 4 days before irradiation and continued for 3 days after irradiation. Intestinal myeloperoxidase (MPO) activities, malondialdehyde (MDA) levels are indicators of oxidative damage while caspase-3 activities reveal apoptosis degree of the small intestine. At histological examination, the terminal ileum tissue was analyzed for morphological changes. Irradiation significantly increased the intestinal MPO and caspase-3 activities, MDA levels and HO-1 expression in comparison to sham control group. OCT treatment was associated with increased HO-1 expression and caspase-3 activity, decreased MPO activity and MDA levels. Histological examination revealed that the intestinal mucosal structure was preserved in the OCT treated group. OCT appears to have protective effects against radiation-induced intestinal damage. This protective effect is, in part, mediated by modification of the inflammatory response and the induction of HO-1 expression.

The efficacy of octreotide in pancreatic and intestinal changes: radiation-induced enteritis in animals

Radiation enteritis occurs during the radiotherapy of many intraabdominal malignancies. Radiation induces cellular injury directly and through the generation of free radicals. In the present study we aimed to investigate the effect of octreotide (OCT) pretreatment in irradiation-induced enteritis. For this aim, rats were injected with 50 microg/kg OCT 4 days before irradiation and continued for 3 more days, until sacrifice. Then intestinal and pancreatic myeloperoxidase (MPO) activities and intestinal malondialdehyde (MDA) levels of the rats were measured. Irradiation significantly increased intestinal and pancreatic MPO activities and MDA levels of intestinal tissues in comparison to those of the sham group. OCT treatment improved this elevation. The histopathologic evaluation of the mucosal structure was also preserved in the OCT-treated group. Inflammation of pancreatic tissue was also confirmed with histopathological examinations. In the irradiation group, NFkappa-B overexpression was detected. OCT treatment decreased the end organ damage and inflammation of the small intestine. In conclusion, OCT appears to have beneficial effects on intestinal and pancreatic damage in abdominal irradiation through the inflammatory process.

Early disturbance of microvascular function precedes chemotherapy-induced intestinal injury

Intestinal injury 4-48 hr after cytotoxic therapy (etoposide phosphate, 100 mg/kg body weight [bw], intravenously [i.v.]) was studied in rats using ligated intestinal loops. Chromium-51 ethylenediaminetetraacetic acid ((51)Cr-EDTA) and rubidium-86 chloride ((86)RbCl) were deposited intraluminally to determine the extent of the increase in intestinal permeability and ion channel disruption. Evans Blue (EB) was used for detection of endothelial leakage. Intestinal morphology was documented. Endothelial dysfunction, as observed by an increased extravasation of EB, was evident already 4 hr after cytotoxic therapy. Intestinal epithelial injury, as observed by an increase in (51)Cr-EDTA permeation and a decrease in (86)Rb absorption, occurred after 48 hr. Finally, histology disclosed a reduced crypt cell proliferation, displayed as a decrease in Ki67-positive cells. The findings suggest that, in the development of intestinal injury after cytotoxic therapy, endothelial disruption is an early event, whereafter epithelial dysfunction and crypt stem cell arrest occur. This knowledge could be of importance in the design of future intervention trials.

99mTc demotate 1: biodistribution and elimination characteristics in rats

BACKGROUND AND METHODS

In this study, we investigated the biodistribution and elimination characteristics of a new radiolabelled somatostatin analogue, 99mTc demotate 1, in rats by in-vivo biodistribution and elimination experiments, perfused rat liver and kidney experiments and micro-autoradiography of renal tissue.

RESULTS

Rapid clearance from blood and most organs was found. High and long-term uptake in organs with high density of somatostatin receptors (the adrenals and pancreas) and in stomach and intestine was reduced in non-radiolabelled octreotide pretreated animals. The predominant urine excretion was associated with an accumulation of 99mTc demotate 1 in the kidney, mainly in the renal cortex. This uptake was not affected by non-radiolabelled octreotide pretreatment.

CONCLUSION

99mTc demotate 1 is a prospective radiopharmaceutical for use in human medicine in somatostatin receptor-positive tumour imaging and its potential should be confirmed in further experiments and clinical trials.

The experience of fatigue, other symptoms and global quality of life during radiotherapy for uterine cancer

This paper reports on how patients with uterine cancer, receiving radiotherapy, experience fatigue, other symptoms and global quality of life. The results showed that fatigue increased significantly during the therapy. Also the other symptoms; loss of appetite, nausea/vomiting and diarrhoea increased significantly and were significantly correlated to general fatigue. Global quality of life decreased significantly during treatment compared to baseline. The variation of the level in general fatigue after completed therapy was only explained by the level of general fatigue experienced at baseline. The result can lead to a better understanding of the severity of symptoms experienced by patients with uterine cancer treated with radiotherapy.

Acute diarrhea during pelvic irradiation: is small-bowel volume effect different in gynecologic patients with prior abdomen operation or not?

OBJECTIVE

To evaluate volume effect of small bowel for diarrhea during pelvic irradiation in gynecologic patients with or without prior abdomen operation.

METHODS

From January 1996 through December 2003, 759 patients undergoing 4-field pelvic irradiation for cervical or uterine cancer were analyzed. Whole pelvic (WP), modified whole pelvic (MWP), or lower pelvic (LP) irradiation were delivered initially. According to contrast medium within small bowel in simulation films, we categorized the small-bowel volume of full dose related to WP fields as small-volume and large-volume groups. We recorded the severity of diarrhea until 39.6 Gy/22 fractions of pelvic irradiation. The actuarial rates of overall and moderate to severe diarrhea were compared among different groups.

RESULTS

Significantly more large-volume distribution (85%) was noted in patients >60 years without prior operation (P < 0.001). Large-volume distribution was 53%, 65%, and 82% in post-operative patients with no diarrhea, mild diarrhea, and moderate to severe diarrhea (P = 0.002), respectively. The corresponding rate was 79%, 77%, and 80% in patients without prior abdomen operation (P = 0.869). In multivariate analysis, prior operation with LP fields (P = 0.005) and prior operation with small volume (P = 0.031) were significantly protective factors for overall diarrhea. The latter was also a protective factor for moderate to severe diarrhea (P = 0.026). Prior operation could diminish overall diarrhea in patients without simultaneous large-field (WP or MWP) and large-volume. Large volume was a significant factor of overall (P = 0.014) and moderate to severe (P = 0.004) diarrhea in large-field patients with operation. The volume effect did not exist in those patients without operation.

CONCLUSION

Age and operation can change small-bowel distribution. Prior operation may attenuate diarrhea if irradiated volume of small bowel is small. There is a volume effect in post-operative rather than non-operative patients receiving large-field irradiation. More practical dose-volume evaluation of small bowel may be applied for volume effect in gynecologic patients without prior operation.

Octreotide for Refractory Diarrhea Associated with Capecitabine

Objective:

To describe the effect of low-dose subcutaneous octreotide on refractory diarrhea associated with capecitabine.

Case Summary:

A 67-year-old white woman with recurrent metastatic breast cancer received monotherapy with capecitabine after failing docetaxel. The first 2 consecutive capecitabine cycles were well tolerated. The patient, however, developed severe watery diarrhea after the third cycle. Diphenoxylate, atropine, loperamide, and attapulgite, along with conventional supportive measures, did not significantly improve the diarrhea, resulting in prolonged hospitalization. Octreotide 100 μg every 8 hours was administered subcutaneously. Immediate relief in stool frequency was observed during the first day. The stool became more formed on the next day. The patient was ready for discharge after learning how to perform subcutaneous injections. Octreotide was continued at home for 3 more days. After discontinuation of octreotide, no recurrent diarrhea occurred. Capecitabine was not reinitiated.

Discussion:

Diarrhea is a potentially life-threatening complication from treatment with capecitabine, an oral fluoropyrimidine analog. Octreotide has shown efficacy for diarrhea from many conditions, including chemotherapy with irinotecan and intravenous fluoropyrimidines such as fluorouracil. Our report suggests that octreotide also is effective for diarrhea associated with capecitabine. The patient's rapid response shortened her hospital stay and improved her quality of life.

Conclusions:

In our patient, subcutaneous octreotide, along with other conventional antidiarrheal therapies, was associated with rapid resolution of refractory diarrhea attributed to capecitabine.

Gastrointestinal mucositis

OBJECTIVE

To review the management of radiotherapy- and chemotherapy-induced gastrointestinal mucositis.

DATA SOURCE

Articles and research studies.

CONCLUSION

Gastrointestinal damage is becoming a common dose-limiting toxicity. However, there is only limited research into the mechanism and possible treatment of this toxicity.

IMPLICATIONS FOR NURSING PRACTICE

It is important to document the frequency and severity of gastrointestinal mucositis, and to alleviate symptoms wherever possible.

Overview of radiation- and chemoradiation-induced diarrhea

OBJECTIVES

To describe the pathophysiology, incidence, and impact of radiation-induced diarrhea (RID), and to highlight the radiation oncology nurse's role.

DATA SOURCES

Primary and tertiary literature, and clinical experience.

CONCLUSION

RID is a frequent complication of pelvic radiation, both when given alone and with chemotherapy. RID can significantly affect patient quality of life. Since diarrhea may be a difficult topic for patients to discuss, special care needs to be taken to avoid underdiagnosis of this problem.

IMPLICATIONS FOR NURSING PRACTICE

The oncology nurse is uniquely situated to monitor patients for the development of RID, assess its severity and provide guidance to the health care team on the patient's status.

How Safe is Adjuvant Chemotherapy and Radiotherapy for Rectal Cancer?

Over the last three decades, a series of clinical trials have led to the use of adjuvant pelvic radiotherapy and chemotherapy in high-risk (T3-4 or N1) rectal cancer. There is a need to improve patient selection in order to identify the group most at risk for recurrent disease. The toxicity of adjuvant therapy should be factored into this consideration. The optimal sequencing of adjuvant therapy before or after surgery, the use of short- or long-course radiotherapy, and the utility of concurrent chemotherapy is currently being examined in randomized controlled trials (RCTs). The aim of this report was to review the morbidity and mortality in all RCTs of adjuvant therapy for rectal cancer.

Management of acute cancer treatment-induced diarrhea

OBJECTIVES

To describe the dietary and pharmacologic management of acute CTID.

DATA SOURCES

Primary and secondary literature, and clinical experience.

CONCLUSION

When dietary strategies do not work, or when patients present with grade 3/4 diarrhea, pharmacologic intervention is required. First-line therapy should be initiated quickly with loperamide or diphenoxylate/atropine in recommended doses. Somatostatin analogues are effective as second-line therapy or as first-line therapy for patients with grade 3/4 diarrhea.

IMPLICATIONS FOR NURSING PRACTICE

Oncology nurses should strive to match treatment with the severity of symptoms of CTID. Whatever therapy is chosen, the goal must be to quickly control this debilitating and potentially life-threatening side effect so that primary chemotherapy and/or radiation therapy may be resumed and completed.

Rectal cancer: preoperative versus postoperative irradiation as a component of adjuvant treatment

The search for improved disease control and survival for resectable but high-risk rectal cancers has led to studies that combine all 3 modalities. For surgically resected, high-risk rectal cancers, postoperative chemoradiation has been shown to improve both disease control (local and distant) and survival (disease free and overall) and was recommended as standard adjuvant treatment at the 1990 National Institute of Health Colorectal Cancer Consensus Conference. Three randomized studies showed improved overall survival (OS) and local control for patients treated with postoperative irradiation and chemotherapy when compared with surgery alone or surgery plus irradiation control arms. These include 2 US trials, Gastrointestinal Tumor Study Group and Mayo/North Central Cancer Treatment Group (NCCTG) and a Norway trial. Although most preoperative external beam radiation trials show reductions in local relapse with the addition of preoperative EBRT to resection, only the large Swedish trial of approximately 1,100 patients showed a survival improvement when compared with a surgery alone control arm for resectable primary rectal cancers. In a recent pooled analysis of 3 postoperative adjuvant rectal cancer trials (NCCTG 794751, NCCTG 864751, and GI Intergroup 0114) survival and disease relapse were dependent on both TN and NT stage of disease (N substage within T stage and T substage within N stage). Even among N2 patients (4 or more positive nodes), T substage influenced 5-year OS (T1-2, 69%; T3, 48%; and T4, 38%; P <.001). Ongoing randomized trials are being conducted for patients with high-risk, resectable primary rectal cancers. The intent is to help define optimal combinations of postoperative chemoradiation (US GI Intergroup), to test sequencing issues of preoperative versus postoperative chemoradiation (Germany trial), and to determine if concurrent and maintenance 5-FU and leucovorin add to the benefits found with preoperative irradiation (European Organization for Research and Treatment of Cancer). For subsequent trials, it may be preferable to perform separate studies, or a planned statistical analysis, for different risk groups of patients (low, intermediate, moderately high, and high), as defined in the rectal cancer pooled analysis.