Surgical management of radiation injury of the small and large intestine

Review of incomplete macroscopic resections (R2) in rectal cancer: Treatment, prognosis and future perspectives

Colorectal cancer is one of the most prevalent tumours, but with improved treatment and early detection, its prognosis has greatly improved in recent years. However, when the tumour is locally advanced at diagnosis or if there is local recurrence, it is more difficult to perform a complete tumour resection, and there may be a residual macroscopic tumour. In this paper, we review the literature on residual macroscopic tumour resections, concerning both locally advanced primary tumours and recurrences, evaluating the main problems encountered, the treatments applied, the prognosis and future perspectives in this field.

Surgery for radiation injury to the large intestine. Variables influencing outcome

PURPOSE

Surgery for colorectal radiation injury is technically difficult and often followed by complications. This study evaluates factors affecting outcome.

METHODS

A retrospective 30-year review was carried out. Preoperative characteristics and operative variables were correlated with morbidity, mortality, and success in providing symptomatic relief.

RESULTS

A total of 60 cases and 75 colon and rectal lesions were analyzed. After surgery, the morbidity rate was 65 percent, and the mortality was 6.7 percent. A successful outcome in providing symptomatic relief was achieved in 71.7 percent of cases. When comparing success after operations for the different lesions (stricture, 78.1 percent; hemorrhage, 64.3 percent; perforation, 100 percent; and fistula, 54.5 percent), the presence of a fistula was associated with symptomatic relief significantly less often than the remainder (P = 0.03). The type of operation had no effect on success rate: 72 percent for diversion, 66.7 percent for resection, and 83.3 percent for bypass. Morbidity and mortality rates were not significantly influenced by site of lesions, type of lesions, or choice of surgical operation. A permanent stoma was necessary in 70 percent of patients.

CONCLUSIONS

The morbidity for surgical treatment of large bowel radiation injury is substantial, and largely unrelated to the type and location of the radiation lesion, as well as the type of operation. Success rates are reasonably high, but worst after fistula repair. The selection of therapy (medical, endoscopic, surgical) for radiation-induced colorectal lesions must take into account numerous factors and be highly individualized.

Radiation injuries of the colon and rectum

Approximately 5% to 10% of patients receiving abdominopelvic radiation therapy will develop a colon or rectal injury. Thorough evaluation of the patient to determine the extent of the injury and the presence of concomitant lesions and to rule out recurrent malignancy is urged. Many radiation complications can be managed with medical regimens. Although colostomy remains a valuable and frequently utilized mode of treatment, it is by no means the sole alternative when surgical intervention is required. Rectal resection with colorectal or coloanal anastomosis can be performed safely for some injuries involving the distal rectum. Surgery for irradiated bowel should be focused on minimizing dissection to minimize injuries and on providing healthy non-irradiated tissues to provide adequate blood supply to promote healing. Patients who have received abdominopelvic radiation are at greater risk of developing colorectal cancer, and cancer surveillance should be commenced 5 years after completion of therapy.

The prognostic importance of site and type of radiation-induced bowel injury in patients requiring surgical management

A multivariate analysis was performed to determine the outcome, and factors prognostic for outcome, in 57 patients requiring surgical intervention for radiation bowel injury. The actuarial 2- and 5-year cause-specific survival (CSS) was 76 and 74%, respectively, with a median follow-up of 62 months for the survivors. The median time from surgery to death from complications was 4 months. Identified sites of injury were both large and small bowel. The types of injury were defined as stricture, perforation, inflammation, and fistula. At surgery 9 patients had more than one site, and 15 patients had more than one type of injury. Cox proportional hazards regression models relating survival to individual patient characteristics were constructed using surgical procedure, radiation-surgery interval, age, stage, radiotherapy technique and dose, and the individual sites and types of injuries. Only the site of injury was found to be of prognostic significance for CSS (P less than 0.03). However, when the site and type of injury were recoded as single or multiple, Cox regression analysis found both the site (P = 0.008) and the type (P = 0.02) of injury to be statistically significant for CSS (favoring single sites and types). Stepwise multivariate regression analysis found type of injury to be insignificant when site of injury was already in the model. Ileal damage was associated with the lowest CSS of any single site of injury (56%) and also appeared to be responsible for the poor CSS of those with multiple sites of injury (46%).

Late radiation injury of the small intestine. Clinical, pathophysiologic and radiobiologic aspects. A review

Transient symptoms due to injury of the intestinal mucosa occur in the majority of patients receiving radiation therapy for pelvic or intra-abdominal neoplasms. Late (chronic) radiation enteropathy, although less common, is a more serious condition, associated with high morbidity and mortality. The manifestations of late radiation enteropathy are primarily due to changes in compartments other than the mucosa, such as intestinal wall fibrosis and obliterating vascular sclerosis. As a result of recent clinical and experimental studies, considerable knowledge about the pathogenesis, dose-response relationship, and time-course of development of late radiation enteropathy has been obtained. Also, the advent of new animal models has facilitated studies of time-dose-fractionation relationships in the intestine. The present paper summarizes clinical, pathophysiologic, and radiobiologic aspects pertinent to the development of chronic intestinal radiation injury.

Surgical treatment of intestinal radiation injury

A review of 43 consecutive patients requiring operation for serious intestinal radiation injury was undertaken to elucidate the efficacy of surgical treatment. The most common site of radiation injury was the rectum (19 cases), followed by the small bowel (13 cases), the colon (7 cases), and the combination of these (4 cases). The overall operative mortality was 14%; morbidity, 47%; and the postoperative symptom-free period, 18 +/- 30 months. Colostomy (N = 20) carried the lowest risk of mortality, 0%, as compared with resection (N = 17) and bypass procedure (N = 6), which were accompanied by the mortalities of 24% and 33%, respectively. During the follow-up (3-13 years) 12 patients (28%) died of recurrent cancer and 9 patients (21%) of persistent radiation injury, which yielded an overall mortality of 65% after resection and 50% and 65% after bypass and colostomy procedures, respectively. Continuing radiation damage led to 15 late reoperations. Ten of these were performed after colostomy, four after resection, and one after bypass. We conclude that colostomy cannot be regarded as a preferred operative method, because it does not prevent the progression of radiation injury and because it is, for this reason, associated with a higher late-complication rate. A more radical surgery is recommended but with the limitation that the operative method must be adapted to the operative finding.

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.

Surgical treatment of radiation injuries of the colon and rectum

Between 1950 and 1983, radiation-induced proctitis was diagnosed proctoscopically in 720 patients at the Mayo Clinic. Sixty-two patients with severe colorectal symptoms were treated surgically. The interval from cessation of radiotherapy to onset of symptoms ranged from 3 weeks to 24 months (mean 33 months). The 62 patients underwent a total of 143 operations with 8 operative deaths (13 percent), and 40 patients (65 percent) had 61 complications. The morbidity rate was lower after colostomy alone (44 percent in 27 patients) than after more aggressive operations (80 percent in 35 patients). Transverse loop colostomy and descending colostomy were safer than sigmoid colostomy. The dissection adhesions, opening of tissue planes, and careless manipulation of intestine may result in necrosis and perforation of the intestine, bladder, or vaginal wall; these were the main causes of fecal and other internal fistulas in our study.

Safety of low anterior resection in the presence of chronic radiation changes in dogs

Thirty mongrel dogs underwent 4000- or 5000-rad single treatment orthovoltage irradiation to the pelvis according to the nominal standard dose equation. Following a resting period of six months, 21 dogs were randomized to low anterior resection with either stapled or handsewn anastomoses. Anastomotic leaks were evaluated on clinical and radiographic grounds. The radiographic leak rate was 81 percent for sutured and 0 percent for stapled anastomoses. The clinical leak rate was 18 percent for sutured and 0 percent for stapled anastomoses. The difference between the 4000- and 5000-rad groups was not significant. The data suggest that late effects of irradiation do not preclude the safe construction of low anterior anastomoses, and that the circular stapling device is superior to hand-sewn techniques.

Surgical aspects of intestinal injury due to pelvic radiotherapy

Seventy-one patients with intestinal injury secondary to pelvic irradiation had predominantly large bowel lesions. Seventeen cases were treated conservatively and 54 came to surgery, 28 patients having more than one operation. Following this essentially salvage surgery there were more ileal than colonic anastomotic leaks. Thirty-four patients died during the follow-up period (2-12 years), 19 from recurrent malignancy, and nine as a result of continuing radiation effects. Seventy per cent of the patients who had a radiation fistula died as a result of malignancy. Of 42000 cases of pelvic malignancy treated by irradiation over the decade 1972-1982, surgical referrals for complications constituted 1.7%, with an overall radiation-related mortality of 0.2%. It is our opinion that colostomy alone has little part to play in this condition, and a policy based on excisional surgery is suggested.

Ultrastructural aspects of capillary function in irradiated bowel. An experimental study in the cat

Irradiated small intestine of the cat has decreased capillary function measured as capillary filtration. This decrease may be due to changes in capillary permeability or decreased capillary area. An electron microscopic study was carried out to examine whether there were any ultrastructural changes consistent with impaired permeability. Cat ileum was irradiated with doses from 10 to 25 Gy and examined 4 days, 1 month, and 4 months after irradiation. In the acute phase (4 days) degenerative endothelial changes were seen and increased with dose. Congestion and microthrombi were also observed. One month after irradiation endothelial changes were still seen after 20 and 25 Gy, and an aggregation of fibrous matter adjacent to the capillary wall was prominent. The endothelial changes were subtle after 4 months, but the pericapillary and stromal fibrosis increased, and an increasing number of collagen fibrils appeared. Micropores disappeared after 20 and 25 Gy but returned later. Pinocytic vesicles were observed after all doses and intervals. The initial decrease in capillary filtration coefficient after irradiation may partly be due to permeability changes caused by endothelial degeneration, whereas the late decrease parallels the increasing pericapillary fibrosis.

Radiation injury of the rectum: evaluation of surgical treatment

One hundred four patients, 80 women and 24 men, with radiation injury of the rectum following treatment for gynecologic and urologic malignancy were studied. In 50 patients, the rectal injury was treated surgically; 54 patients were treated conservatively. The age and sex distributions were the same in each group. In 63 patients, symptoms developed one month to one year after radiotherapy. The longest latent interval was 17 years. Of the 50 surgical patients, 23 had associated small bowel injury. The indications for surgery for the rectal injury were 1) proctitis unresponsive to conservative measures in 14 patients, 2) rectal stricture or fistula or both in 32, and 3) rectosigmoid perforation in four. Forty-one patients had external diversions. Eleven had intestinal continuity restored; six of the 11 had required the stoma for proctitis unresponsive to medical measures. Nineteen patients did not undergo colostomy closure, although symptoms wer greatly improved. Diversion alone was insufficient treatment in the remaining 11 patients. Twenty-six patients died. The 12 deaths in the surgical group comprised four due to residual malignancy, four from postoperative complications, and four from unrelated causes. Of the 14 deaths in the nonsurgical group, 11 died of the primary malignancy and three of unrelated causes. Diversion is considered the safest form of treatment for rectovaginal fistulae, rectal strictures, and proctitis unresponsive to medical measures. Intestinal resection resulted in sharp rise in the morbidity and mortality rates.

Operative management of radiation injuries of the intestinal tract

A review of forty cases of radiation-induced gastrointestinal injuries is presented. Based on this experience and reports in the literature, preoperative management and operative technics are discussed. The increased risk of radiation bowel injury is recognized in patients who have had previous operations. Preradiation contrast studies are advised to identify trapped loops of intestine in the pelvis. Small bowel resection is recommended with localized segments of disease. Bypass operations are preferable to avoid any extensive dissections. Bypass operations have anastomotic dehiscence rates similar to those of resections. Proctocolitis is usually managed by diverting colostomy, with resection in a few favorable cases or with treatment failures. Most rectovaginal fistulas are managed by permanent colostomy. Small bowel fistulas are best treated by bypass with partial or total exclusion rather than by primary resection. Vigorous preoperative and postoperative nutritional support and evaluation are vital because of the poor healing qualities of irradiated bowel. Multiple operative procedures should be anticipated because the natural history of radiation bowel injury is slowly progressive.

Bile salt malabsorption in the radiation syndrome

The fraction of faecal activity (FBS) excreted after intravenous administration of 14C-labelled cholic acid was measured in 20 patients with gastrointestinal symptoms (diarrhoea, abdominal pains, malabsorption and rectal haemorrhage) after pelvic irradiation. An FBS excretion of 52 +/- 16 per cent (mean +/- SD) was found in 13 patients with diarrhoea and 18 +/- 12 per cent in 7 patients without diarrhoea. In normals the excretion is not above 18 per cent. Bile salt malabsorption appears to be an important factor in the pathogenesis of diarrhoea in these patients.

The modern enigma of radiation enteropathy: sequelae and solutions

With the extended indications for abdominal and pelvic radiation therapy, administered at higher dosage levels, an increased incidence of radiation injury to the intestine can be anticipated. Increased efforts are urgently needed to develop innovative methods in the detection, prevention, and management of radiation-induced intestinal injury. Fifty cases of radiation enteropathy have been reviewed to highlight problems in management and to suggest preventive and therapeutic measures, both surgical and nonsurgical.