Pathogenesis and treatment of radiation bowel disease: discussion paper

Adjuvant Radiotherapy of the Pelvis with or without Reduced Glutathione: A Randomized Trial in Patients Operated on for Endometrial Cancer

A randomized pilot trial was performed to evaluate the feasibility of administration of glutathione (GSH, 1200 mg, i.v.) as a protector in preventing diarrhea in patients operated on for endometrial cancer and submitted to adjuvant radiotherapy of the pelvis. Diarrhea occurred In 52% of patients In the untreated control group and only in 28% of patients In the GSH-treated group. Our preliminary data indicate that GSH administered before radiotherapy reduced the occurrence of diarrhea from oxidative damage to the intestinal mucosa. A large-scale phase III study is required to obtain definitive conclusions on the protective potential of GSH.

Reduction of the rectal dose in gynecological brachytherapy: modification to the Fletcher-Suit applicator

The dose to the anterior rectal wall is a known limiting factor for the delivery of radical doses of radiation to the uterine cervix with brachytherapy. We developed a modification to the Fletcher-Suit afterloading applicator, consisting of two small inflatable balloons attached to the posterior end of each colpostat. The balloons are connected to catheters that emerge from the vagina attached to the colpostat's handles. The balloons were affixed to the colpostats with a plastic adaptor and are inserted empty. After an anterior radiograph is taken, the balloons are filled with radiological contrast material and a lateral orthogonal film is made. This lateral film taken with the balloons filled with contrast typically shows a significant posterior displacement of the anterior rectal wall away from the vaginal sources. The International Commission on Radiation Units (ICRU) rectal point is then determined 5 mm beyond the posterior boundary of the opacified balloons. We have performed 90 applications using this device, including brachytherapy applications for cervical cancer, as well as vaginal applications for endometrial carcinoma following TAH-BSO. On average, the ICRU rectal point was displaced 14 mm away from the colpostats, thus reducing the dose rate by 60% and resulting in an average dose sparing of about 1000 cGy to the anterior rectal wall.

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.

Gastrointestinal function in chronic radiation enteritis--effects of loperamide-N-oxide

The effects of loperamide-N-oxide, a new peripheral opiate agonist precursor, on gastrointestinal function were evaluated in 18 patients with diarrhoea caused by chronic radiation enteritis. Each patient was given, in double-blind randomised order, loperamide-N-oxide (3 mg orally twice daily) and placebo for 14 days, separated by a washout period of 14 days. Gastrointestinal symptoms; absorption of bile acid, vitamin B12, lactose, and fat; gastric emptying; small intestinal and whole gut transit; and intestinal permeability were measured during placebo and loperamide-N-oxide phases. Data were compared with those obtained in 18 normal subjects. In the patients, in addition to an increased frequency of bowel actions (p < 0.001), there was reduced bile acid absorption, (p < 0.001) a higher prevalence of lactose malabsorption (p < 0.05) associated with a reduced dietary intake of dairy products (p < 0.02), and faster small intestinal (p < 0.001) and whole gut transit (p < 0.05) when compared with the normal subjects. There was no significant difference in gastric emptying between the two groups. Treatment with loperamide-N-oxide was associated with a reduced frequency of bowel actions (p < 0.001), slower small intestinal (p < 0.001), and total gut transit (p < 0.01), more rapid gastric emptying (p < 0.01), improved absorption of bile acid (p < 0.01), and increased permeability to 51Cr EDTA (p < 0.01). These observations indicate that: (1) diarrhoea caused by chronic radiation enteritis is associated with more rapid intestinal transit and a high prevalence of bile acid and lactose malabsorption, and (2) loperamide-N-oxide slows small intestinal transit, increases bile acid absorption, and is effective in the treatment of diarrhoea associated with chronic radiation enteritis.

A simple and effective treatment for hemorrhagic radiation proctitis using formalin

Radiation proctitis is a common complication of radiotherapy for pelvic malignancy. In the more severe form, it leads to intractable or massive hemorrhage, which may require repeated hospital admissions and blood transfusions. Medical therapy in patients with radiation proctitis is usually ineffective, whereas surgery is associated with a high morbidity and mortality. Eight patients (seven females and one male) with hemorrhagic radiation proctitis were treated over a six-month period with endoluminal formalin. The technique used ensured minimal contact with formalin. The median age of the patients was 68 years (range, 42-73 years). Seven patients had had cancer of the uterine cervix, and one patient had had cancer of the prostate treated with radiotherapy at a median time of 30 months (range, 9-46 months) previously. The median duration of time of symptomatic rectal hemorrhage before formalin therapy was eight months (range, 1-12 months). The median number of units of blood transfused previously per patient was four (range, 2-32). The time taken for formalin therapy was 20 minutes (range, 10-70 minutes). One patient required repeat formalin application at two weeks. Bleeding ceased immediately in seven patients after formalin treatment. No further bleeding was noted, nor was any blood transfusion needed, at follow-up at four months (range, 1-6 months). Formalin therapy is a simple, inexpensive, and effective treatment for hemorrhagic radiation proctitis.

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.

Medical management of radiation enteritis--an algorithmic guide

An algorithmic guide to the differential diagnosis and management of late radiation enteritis is proposed. The proposition is based on physiological principles and clinical experience rather than on published reports. Too few patients with late radiation enteritis are seen in most oncology centres for a large prospective trial of the algorithm to be set up, but we hope it will stimulate further investigation.