Control of radiation-induced diarrhea with cholestyramine

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.

Chronic diarrhoea in an oncology patient - Clinical assessment and decision making

Cancer survival is improving rapidly due to advances in treatments that will often involve radiotherapy, chemotherapy and novel biological agents in addition to surgery. This comes at the price of living with chronic symptoms, of which diarrhoea is particularly common. There is good evidence that for many patients these symptoms become part of everyday life, their "normality" is adjusted and symptoms are tolerated even when limiting activities severely. Clinicians often fail to appreciate the impact of these problems, as the focus of follow up tends to be on cancer recurrence. However, the rapid identification of patients in significant trouble can lead to earlier diagnosis of treatable pathologies and improvement of patients' symptoms. The aim of this review is to highlight the mechanisms which cause oncology patients to develop diarrhoea and highlight useful investigational and treatment strategies.

Mechanism of Asbt (Slc10a2)-related bile acid malabsorption in diarrhea after pelvic radiation

Background: Radiation is a mode of treatment for many pelvic malignancies, most of which originate in the gynecologic, gastrointestinal, and genitourinary systems. However, the healthy gut is unavoidably included in the irradiation volume, resulting in undesirable results that manifest as radiation-induced diarrhea (RID), which is the most common side effect of radiation therapy and significantly affects the patients' quality of life. This study aimed to investigate the potential mechanism of diarrhea after pelvic radiotherapy in rats based on the effect of radiation on bile acid homeostasis and sodium-dependent bile acid transporter (Asbt).Methods: In this experimental study, male Sprague-Dawley rats were divided into the following groups - pelvic irradiation, cholestyramine-concurrent radiation, and control groups. The rats in the pelvic irradiation group were irradiated in the pelvic region with 2 Gy per day for five consecutive days. The total bile acid (TBA) levels in the ileum, colon, and feces were measured using automatic biochemical analyzer, and the levels of individual bile acids were evaluated by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). The mRNA and protein expression of Asbt in ileum were assessed by qRT-PCR and Western blot assay. The rats in the cholestyramine-concurrent radiation group were administered with cholestyramine, a bile acid-chelating resin, and concurrent radiation for 5 days. The body weight of rats was monitored daily, and the degree of diarrhea was scored.Results: Diarrhea was observed at 2 and 3 days post-pelvic radiation. The TBA levels were significantly decreased at 4 and 5 days post-radiation in the ileum (p < .01, p < .01) and increased at 4 and 5 days post-radiation in the colon (p < .05, p < .05). The fecal excretions of TBA were significantly increased at 3, 4, and 5 days post-radiation (p < .05). The levels of individual bile acids were significantly decreased in the ileum and increased in the colon and feces, post-radiation. The mRNA and protein expression of Asbt in the ileum gradually decreased with increasing days of pelvic radiation and significantly decreased at 3 and 5 days post-radiation, respectively. Furthermore, a significant decrease in body weight was observed post-pelvic radiation, and cholestyramine administration did not reverse the weight loss. However, the incidence of RID was decreased after administration of cholestyramine.Conclusions: Bile acid malabsorption is partially responsible for RID post-pelvic radiation in rats, and the potential mechanism is related to the downregulation of the ileal Asbt.

Review article: bile acid diarrhoea - pathogenesis, diagnosis and management

BACKGROUND

Bile acid diarrhoea results from imbalances in the homoeostasis of bile acids in the enterohepatic circulation. It can be a consequence of ileal disease/dysfunction, associated with other GI pathology or can be idiopathic.

AIMS

To summarise the different types of bile acid diarrhoea and discuss the currently available diagnostic methods and treatments.

RESULTS

Bile acid diarrhoea is found in up to 40% of patients diagnosed as having functional diarrhoea/IBS-D, and in up to 80% of patients who have undergone ileal resection. It is likely under-diagnosed and under-treated. In idiopathic disease, errors in regulation feedback of fibroblast growth factor 19 contribute to the development of the condition. Clinical therapeutic trials for bile acid diarrhoea have been used to diagnose it, but the ⁷⁵ SeHCAT test is the primary current method. It is sensitive, specific and widely available, though not in the USA. Other diagnostic methods (such as serum measurement of the bile acid intermediate 7α-hydroxy-4-cholesten-3-one, or C4) have less widespread availability and documentation, and some (such as faecal measurement of bile acids) are significantly more complex and costly. First-line treatment of bile acid diarrhoea is with the bile acid sequestrant cholestyramine, which can be difficult to administer and dose due to gastrointestinal side effects. These side effects are less prominent in newer agents such as colesevelam, which may provide higher efficacy, tolerability and compliance.

CONCLUSION

Bile acid diarrhoea is common, and likely under-diagnosed. Bile acid diarrhoea should be considered relatively early in the differential diagnosis of chronic diarrhoea.

Systematic review of agents for the management of gastrointestinal mucositis in cancer patients

PURPOSE

The aim of this study was to review the available literature and define clinical practice guidelines for the use of agents for the prevention and treatment of gastrointestinal mucositis.

METHODS

A systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, and no guideline possible.

RESULTS

A total of 251 clinical studies across 29 interventions were examined. Panel members were able to make one new evidence-based negative recommendation; two new evidence-based suggestions, and one evidence-based change from previous guidelines. Firstly, the panel recommends against the use of misoprostol suppositories for the prevention of acute radiation-induced proctitis. Secondly, the panel suggests probiotic treatment containing Lactobacillus spp., may be beneficial for prevention of chemotherapy and radiotherapy-induced diarrhea in patients with malignancies of the pelvic region. Thirdly, the panel suggests the use of hyperbaric oxygen as an effective means in treating radiation-induced proctitis. Finally, new evidence has emerged which is in conflict with our previous guideline surrounding the use of systemic glutamine, meaning that the panel is unable to form a guideline. No guideline was possible for any other agent, due to inadequate and/or conflicting evidence.

CONCLUSIONS

This updated review of the literature has allowed new recommendations and suggestions for clinical practice to be reached. This highlights the importance of regular updates.

Microbial influences on the small intestinal response to radiation injury

PURPOSE OF REVIEW

Injury to the small bowel from ionizing radiation occurs commonly in patients undergoing cancer therapy and less commonly in instances of accidental radiation overexposure. Several lines of evidence now suggest that dynamic interactions between the host's enteric microbiota and innate immune system are important in modulating the intestinal response to radiation. Here, we will review recent developments in the area of acute radiation enteropathy and examine the current state of knowledge regarding the impact of host-microbial interactions in the process.

RECENT FINDINGS

There is promise in the development and testing of new clinical biomarkers including serum citrulline. Toll-like receptor agonists and innate immune system signaling pathways including nuclear factor-kappa B profoundly alter intestinal epithelial cell apoptosis and crypt survival after radiation exposure. Germ-free conditions, probiotics and antibiotics are each identified as modifiers of disease development and course. A human study suggested that luminal microbiota composition may influence the host's intestinal response to radiation and may change in those developing postradiation diarrhea.

SUMMARY

New knowledge implies that investigations aimed at deciphering the microbiome-host interactions before and after small bowl radiation injury may eventually allow prediction of disease course and offer opportunities for the development of novel therapeutic or prophylactic strategies.

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.

Gastrointestinal symptoms after pelvic radiotherapy: a new understanding to improve management of symptomatic patients

Gastrointestinal symptoms after pelvic radiotherapy, which affect quality of life, are substantially more common than generally recognised and are frequently poorly managed. These symptoms develop because radiation can induce change in one or more specific physiological functions in widely separated parts of the gastrointestinal tract that lie in the path of the radiotherapy beam. Radiation-induced changes are not confined by normal anatomical boundaries. Furthermore, pre-existing subclinical disease might be destabilised because of minor gastrointestinal changes induced by radiotherapy. New diseases might manifest after radiotherapy and be confused with symptoms induced by radiotherapy. Different functional deficits might cause the same symptoms. Many patients have more than one cause for their symptoms, which sometimes need very different treatments. Simple diagnostic tests that are used in other contexts, if applied appropriately to patients with new gastrointestinal symptoms after radiotherapy, can identify the underlying causes of new-onset symptoms. Starting treatment without knowing the cause of the symptom is commonly ineffective because prediction of the combination of treatments needed is difficult. Evidence suggests that many patients have unusual but highly treatable malfunctions of gastrointestinal physiology, which if correctly diagnosed may enable a patient with difficult symptoms to be helped.

Faecal incontinence: A late side-effect of pelvic radiotherapy

AIMS

Despite advances in pelvic radiotherapy, damage to normal tissue can lead to chronic gastrointestinal problems. The frequency with which this affects quality of life is controversial. Faecal incontinence is not widely perceived to be a major issue after pelvic radiotherapy. The aim of this paper is to review the frequency and mechanisms for the development of faecal incontinence after pelvic radiotherapy, and to review treatment options for faecally incontinent patients.

MATERIALS AND METHODS

A search of original literature was carried out using MEDLINE and EMBASE databases from 1966 to 2005.

RESULTS

The reliability of the published data is poor because patients frequently fail to admit to faecal incontinence, and because prospective studies are lacking that assess faecal incontinence as a specific end point using adequate, validated and reproducible methodology. The published rates of late new-onset faecal incontinence after pelvic radiation are between 3% and 53%. Patients treated for prostate rather than gynaecological, bladder, rectal or anal cancer may have a lower rate. Only 8-56% of affected patients state that faecal incontinence reduces their quality of life. Studies examining the physiological changes occurring after radiotherapy are generally not adequately controlled or powered, assessment of ano-rectal function is rarely comprehensive and loss of patients to follow-up frequently makes it difficult to extrapolate results to a wider population. Where there is agreement over the physiological changes that occur after radiotherapy, it is not clear at what threshold these changes cause symptoms. No prospective studies of any non-surgical treatment for faecal incontinence after radiotherapy have been published. Surgery other than colostomy probably carries a high risk of complications in this group of patients, but few data have been published.

CONCLUSIONS

Now that improvements in outcome from combination treatments, including radiotherapy for pelvic cancer, are being achieved, it is time that serious attention is paid to determining how frequently significant gastrointestinal toxicity arises, and how best to optimise the quality of life of long-term survivors.

Radiation enteritis

The frequent use of radiotherapy for abdominal and pelvic malignancies results in an increased risk of radiation enteritis. An increased understanding of the tissue response and the clinical features of radiation enteritis has led to advances in the prevention and management of this condition. Importantly, improvements in the delivery of radiotherapy, including techniques to reduce the amount of exposed small intestine in the radiation field, represent a critical strategy for prevention. Data indicate that radioprotectant agents have the potential to reduce intestinal mucosal injury and may be beneficial in reducing both acute and chronic side effects of radiotherapy.

[Prevention and therapy of acute radiation-related morbidity of the skin and mucosa. II, Recommendations of the literature]

BACKGROUND

In a German multicenter questionnaire, answered by 89 departments, we had examined the strategies to prevent or to treat the acute morbidity of the skin and mucosa associated to radiation therapy. In this work, the recommendations from the literature are compared to the results of the questionnaire.

METHODS

An extensive research on common data information systems (Medline, Cancerlit, DIMDI and others) was performed. The criteria included the organ related morbidity and therapeutic strategies for its reduction. The obtained data were compared to the results from the questionnaire.

RESULTS

The study data found by the research often demonstrate small patient numbers and little convincing results. However, as in the questionnaire, the joint principle seems to be the reduction of acute inflammatory tissue reaction by evasion of bacterial and mycotic overgrowth and reduction of exo- and endogenous toxins.

CONCLUSIONS

Further studies with more convincing results are required.

Intestinal complications of radiotherapy in gynecologic malignancy--clinical presentation and management

Radiation therapy is an effective treatment modality for various gynecologic malignancies. In spite of advances in radiotherapy equipment and techniques over the years, the gastrointestinal and urinary tracts have remained a considerable problem with radiotherapy of the pelvis and abdomen. Clinical presentation of intestinal complications, current concepts of pathophysiology and principles of medical and surgical management are reviewed.

The effects of abdominal irradiation for seminoma of the testis on gastrointestinal function

To evaluate the long-term effects of abdominal irradiation for the treatment of seminoma of the testis on gastrointestinal function, 15 randomly selected patients who had been treated for stage I seminoma of the testis 2-10 years previously had the following parameters of gastrointestinal function evaluated: gastrointestinal symptoms; absorption of bile acid; vitamin B12; lactose and fat; gastric emptying; small intestinal and total gut transit; and intestinal permeability. Results were compared to those obtained in 18 normal volunteers. There was an increased prevalence of gastrointestinal symptoms (P < 0.01) in the patients and stool frequency was above the control range in two of them. Gastric emptying was faster (P < 0.01) in the patients. There were no significant differences in vitamin B12, bile acid, lactose or fat absorption, small intestinal transit or whole gut transit between the two groups, although faecal fat excretion was greater than the control range in three of the patients. At least one parameter of gastrointestinal function was abnormal in 11 of the 15 patients. Patients with right-sided seminoma had a greater bowel frequency when compared to those with left-sided seminoma (P < 0.05). We conclude that mild abnormalities in gastrointestinal function occur frequently when abdominal irradiation is used to treat stage I seminoma.

Effect of pelvic irradiation on gastrointestinal function: a prospective longitudinal study

PURPOSE

Although radiation enteritis is a well-recognized sequel of therapeutic irradiation, the effects of abdominal and/or pelvic irradiation on gastrointestinal function are poorly defined and treatment is often unsuccessful. To determine both the short- and long-term effects of therapeutic irradiation on gastrointestinal function, we performed a prospective study.

PATIENTS AND METHODS

Various aspects of gastrointestinal function were evaluated in 27 patients with potentially curable malignant disease (23 female, 4 male) before the commencement of, during, and 6 to 8 weeks, 12 to 16 weeks, and 1 to 2 years following completion of radiation therapy. Seventeen patients received pelvic irradiation alone and 10 patients received both abdominal and pelvic irradiation. Gastrointestinal symptoms, absorption of bile acid, vitamin B12, lactose, and fat, gastric emptying, small-intestinal and whole-gut transit, stool weight, and intestinal permeability were measured. Results were compared with those obtained in 18 normal volunteers.

RESULTS

All 27 patients completed at least 2 series of measurements and 18 patients completed all 5 series of experiments. During radiation treatment, increased stool frequency (p < 0.001) was associated with decreased bile acid and vitamin B12 absorption (p < 0.001 for both), increased fecal fat excretion (p < 0.05), an increased prevalence of lactose malabsorption (p < 0.01), and more rapid small-intestinal (p < 0.01) and whole-gut (p < 0.05) transit. Although there was improvement in most of these changes with time, at 1 to 2 years after the completion of irradiation, the frequency of bowel actions was greater (p < 0.001), bile acid absorption was less (p < 0.05), and small-intestinal transit was more rapid (p < 0.01) when compared with that of baseline and the normal subjects. At this time, at least 1 parameter of gastrointestinal function was abnormal in 16 of the 18 patients. Stool weight was greater (p < 0.05) and whole-gut transit faster (p < 0.01) in patients who received both pelvic and abdominal irradiation, when compared with those who received pelvic irradiation alone. Stool frequency (p < 0.001) and fecal fat excretion (p < 0.05) were greater in those patients who had surgery before radiation therapy.

CONCLUSION

Pelvic irradiation is usually associated with widespread, persistent effects on gastrointestinal function.

A retrospective study of the effects of pelvic irradiation for carcinoma of the cervix on gastrointestinal function

PURPOSE

To evaluate the prevalence of disordered gastrointestinal function following therapeutic irradiation.

METHODS AND MATERIALS

Gastrointestinal function was evaluated in 30 randomly selected patients who had received pelvic irradiation for treatment of carcinoma of the cervix between 1 and 6 years previously. Each patient underwent evaluations of (a) gastrointestinal symptoms (b) absorption of bile acid, vitamin B12, lactose and fat (c) gastrointestinal transit: gastric emptying, small intestinal transit and whole gut transit and (d) intestinal permeability. Results were compared with those obtained in 18 normal volunteers.

RESULTS

Stool frequency was above the control range in five patients and had increased (p < 0.001) since radiotherapy treatment. Bile acid (p < 0.001) vitamin B12 (p < 0.01) and lactose (p < 0.01) absorption were less in the patients when compared with the control subjects. Bile acid absorption was below the control range in 14 of the 30 patients. Dietary calcium intake was lower (p < 0.05) in those patients with lactose malabsorption. Gastric emptying (p < 0.01) and small intestinal transit (p < 0.01) were more rapid in the patients. Both small intestinal (r = -0.39, p < 0.05) and whole gut (r = -0.45) transit were inversely related to stool frequency. Either bowel frequency, bile acid absorption, vitamin B12 absorption was outside the control range in 19 of the 30 patients.

CONCLUSION

Abnormal gastrointestinal function is essentially an inevitable long-term sequel of pelvic irradiation.

The influence of low fat, low lactose diet on diarrhoea during pelvic radiotherapy

In a prospective clinical trial 143 women undergoing pelvic radiotherapy for gynaecological malignancies, were randomized to receive either a low-fat, low-lactose diet (intervention group) or a regular diet (control group) in order to evaluate the possible impact of diet therapy on radiation induced diarrhoea, nausea and vomiting. The daily number and consistency of stools, use of antidiarrhoeal agents, nausea and vomiting were recorded before radiotherapy was begun (week 0), in the last week of therapy (week 6) and 6 weeks after the end of therapy (week 12). The intervention group used half the amount of antidiarrhoeal agents in week 6, than used by the control group (mean 0.6 tablets per day versus 1.1, p < 0.01). 14 patients (23%) in the intervention group reported diarrhoea, versus 32 (48%) in the control group (p < 0.01). In week 12 there were no differences in the use of antidiarrhoeal agents and the prevalence of diarrhoea between the groups.

Chronic diarrhoea after radiotherapy for gynaecological cancer: occurrence and aetiology

The occurrence of chronic diarrhoea was evaluated in 173 consecutive patients previously treated with radiation for gynaecological cancer. A survey of gastrointestinal symptoms showed a high frequency of diarrhoea; 13% of the patients had 21 or more bowel movements a week and 3% had 28 or more. Significantly more patients who had a cholecystectomy were in the group with diarrhoea (chi 2 = 6.26; p less than 0.02). Twenty patients with chronic or intermittent diarrhoea were subject to extended gastrointestinal investigation. Bile acid malabsorption was evaluated by the 75Selenahomocholic acid-taurine test (SeHCAT). Bile acid malabsorption was found in 13 (65%) of the 20 patients further investigated, of whom seven had extremely low whole body retention values, which is consistent with severe malabsorption. The results suggest that bile acid malabsorption is a common cause of diarrhoea after radiation treatment for gynaecological cancer. Bacterial contamination was diagnosed in nine patients (45%) by the [14C]-D-xylose breath test or by the cholyl-[14C]-glycine breath test in combination with a normal test for bile acid malabsorption. All patients with vitamin B-12 deficiency, who were tested for bile acid malabsorption, had low retention times for the SeHCAT (p = 0.05). A significant decline in the frequency of diarrhoea was found after treatment with antibiotics or bile acid sequestrants, or both, in combination with a reduced fat diet.

Natural history and surgical management of radiation enteritis

Radiation enteritis is an increasing problem. The effect of ionizing radiation is due to a direct effect on proliferating cells and due to a progressive obliterative vasculitis. Predisposing factors include the dose of radiation, combination with chemotherapy, previous operations and vascular disease. Management is related to the stage of disease at presentation, and tailored to the clinical problem. Surgical management must take into account the poor healing associated with irradiated intestine.

Absence of bile acid malabsorption as a late effect of pelvic irradiation

The pathophysiology of chronic radiation-induced diarrhea was evaluated in 28 patients who had undergone pelvic irradiation for gynecologic neoplasms 2 to 7 years previously. Twenty-seven patients undergoing radiotherapy with techniques that did not require abdominal or pelvic irradiation served as controls. The glycine conjugates of cholic acid (GC) were measured in serum by radioimmunoassay. Fasting and 2 hr. pp GC levels for the pelvic irradiated patients were 11.0 +/- 11.1 (mean +/- SD) and 24.8 +/- 17.3 micrograms/dl. Fasting and 2 hr. pp GC levels for controls were 12.6 +/- 7.4 and 28.0 +/- 14.7. There were no significant differences in the post-prandial increases in serum GC between pelvic irradiated patients and controls (p = .23, Type II error probability = .13). There was also no significant difference in the 2 hr. pp and fasting GC ratio (p = .39). There was significant difference between the stool frequency (p less than .01) and the prevalence of diarrhea (p less than .02) between pelvic irradiated patients and controls. The data suggest that bile acid malabsorption due to ileal dysfunction is not an inevitable late complication of pelvic irradiation and is not the major determinant in the pathophysiology of chronic radiation-induced diarrhea.

The pathogenesis of post-irradiation chronic diarrhoea: measurement of SeHCAT and B12 absorption for differential diagnosis determines treatment

The absorption of vitamin B12 and of a synthetic bile acid analogue 75SeHCAT was measured simultaneously in 26 patients presenting with persistent diarrhoea following pelvic irradiation for treatment of carcinoma of the cervix. Four groups were identified, namely patients with isolated bile acid malabsorption, patients with isolated B12 malabsorption, patients with malabsorption of both and those with malabsorption of neither compound. The therapeutic implications are different for each. Measurement of B12 and bile acid absorption comprises an important new test for the management of patients with this disabling and unpleasant complication of radiotherapy.

Critical evaluation of the role of nutritional support for radiation therapy patients

Nutritional intake or absorption may be compromised by radiation therapy (RT) when large portions of the gastrointestinal tract are treated. Dietary counseling, oral supplements, tube feedings and intravenous hyperalimentation (IVH) have been employed to limit weight loss and lessen intestinal RT side effects. Unfortunately, no prospective study reviewed has shown improved tumor control or patient survival. Special diets and IVH have also been employed in select patients to relieve chronic malabsorption from severe radiation enteritis.

A clinical trial evaluating cholestyramine to prevent diarrhea in patients maintained on low-fat diets during pelvic radiation therapy

A prospective randomized trial to determine the value of a low fat diet with or without cholestyramine in the treatment of acute intestinal complications of pelvic irradiation is presented. A total of 35 patients receiving pelvic irradiation were entered in the study and all patients had received a 40 gm fat diet. The group was then randomized to receive either placebo (17 patients) or cholestyramine (18 patients). Diarrhea occurred in six out of 16 evaluable patients in the control group and only one of the 17 evaluable patients in the cholestyramine group. The frequency of diarrhea and the diarrhea scale remained high in the placebo group in the entire observation period. Statistical analysis had revealed better diarrhea control in the cholestyramine group (p = less than 0.05). In this report mechanism by which diarrhea occurs following pelvic irradiation is discussed. The adverse effects associated with the use of cholestyramine have been presented. It was concluded that cholestyramine is effective in preventing acute diarrhea induced by pelvic irradiation in patients receiving a low fat diet but is associated with side effects.

Colestipol hydrochloride prophylaxis of diarrhea during pelvic radiotherapy

Thirty-three patients were randomized prior to pelvic radiotherapy to receive the bile acid-sequestering resin colestipol hydrochloride, 5 grams qid, during the entire time of their therapy or diphenoxylate hydrochloride and atropine sulfate 2.5-20 mg per day (control) if they experienced diarrhea. The colestipol patients also took diphenoxylate if they had diarrhea. The patients in the colestipol group often experienced nausea, vomiting, and abdominal cramps and 8 were forced to discontinue the drug. There was no difference in the weekly stool frequency between the colestipol and the control patients but the colestipol patients who took at least 50% of the prescribed dose required fewer diphenoxylate tablets than the controls. The data suggest that colestipol hydrochloride is not of value in preventing radiation-induced diarrhea because of the side effects associated with the drug, but the theory on which the use of bile acid-sequestering agents is based may be correct.

Treatment of dermatitis herpetiformis with cholestyramine

Two patients with clinically and histologically typical dermatitis herpetiformis showed a dramatic clearing of their skin lesions in association with an oral dose of 4 g of cholestyramine three times a day. Reappearance of the lesions occurred on the discontinuance of the therapy, followed by remission on resumption of cholestyramine. It is postulated that the non-absorbable anion exchange resin, cholestyramine, may have bound and hence blocked absorption of an unidentified compound (possibly gluten, iodine, or endotoxin) critical to the pathogenesis of dermatitis herpetiformis.