INTRODUCTION — Radiation to the abdomen or pelvis can damage intestinal structures, especially the ileum (radiation enteritis) and rectum (radiation proctitis). Although most early radiation injuries respond to supportive care alone, late effects of radiation, which may take months to years to manifest, often require surgical intervention.
In this topic, we discuss the surgical approach to radiation enteritis. Clinical manifestations, diagnosis, and medical management of radiation-related injuries are discussed elsewhere, including:
●Gastrointestinal toxicity (see "Overview of gastrointestinal toxicity of radiation therapy")
●Radiation proctitis (see "Radiation proctitis: Clinical manifestations, diagnosis, and management")
●Chronic radiation enteritis (see "Diagnosis and management of chronic radiation enteritis")
●Gynecologic malignancies (see "Treatment-related toxicity from the use of radiation therapy for gynecologic malignancies")
●Radiation-induced fibrosis (see "Clinical manifestations, prevention, and treatment of radiation-induced fibrosis")
INDICATIONS FOR SURGERY — Late changes of radiation enteritis have largely been attributed to progressive vasculitis within the wall of the bowel. As a result, the bowel may ulcerate, stenose, or perforate, which may cause malnutrition, depending upon the volume of bowel affected [1]. Medical therapy for these complications is discussed elsewhere. (See "Diagnosis and management of chronic radiation enteritis", section on 'Approach to management'.)
Complications from radiation enteritis that are refractory to medical therapy often require surgical treatment. The indications for surgical treatment of radiation enteritis are summarized below.
Obstruction — Acute intestinal obstruction is unusual in chronic radiation injury to the intestine. However, strictures usually form over time, and this gradual deterioration eventually leads to partial or complete obstruction. Surgery is indicated when symptoms such as bloating (partial obstruction) or nausea and vomiting (complete obstruction) become intractable. In two small series, obstruction was present in 25 to 53 percent of patients referred for surgery for radiation enteritis [2,3]. In rare cases, gastric outlet obstruction has developed due to Yttrium-90 nontarget embolization (used to treat liver tumors) [4-7].
Fistula — Radiation-induced intestinal fistulae require surgical correction if they do not close with nonoperative management. In the same two series mentioned above, intestinal fistulae were present in 17 to 50 percent of patients referred for surgery for radiation enteritis [2,3]. (See "Enterocutaneous and enteroatmospheric fistulas", section on 'Surgical techniques'.)
Perforation — Chronic radiation enteritis may result in intestinal perforation that requires immediate surgical attention [8]. In one series of 95 women treated with pelvic radiation for cervical cancer, 7 percent developed perforation of the ileum. The time from the completion of radiotherapy to perforation varied widely from 2 to 58 months (median of six months) [9].
Bleeding — Radiation damage to intestinal mucosa causes ulcerations, friability, and bleeding. Either catastrophic or slow but refractory gastrointestinal bleeding from the small bowel requires surgical intervention. In this case, accurate localization of the bleeding source is important prior to surgery as surgical exploration may not readily identify the bleeder(s). (See 'Bleeding patients' below.)
Neoplasm — Abdominopelvic radiation can induce secondary neoplasms. In one study, patients with Hodgkin's lymphoma treated with chemotherapy and radiation had rates of stomach, small intestine, and pancreatic cancer that were more than twice the rates in the general population (relative risk 2.5, 95% CI 1.5-3.5) [10]. Most secondary cancers arose within the fields of irradiation 10 or 20 years after treatment.
In this series, many gastrointestinal neoplasms secondary to radiation produced symptoms (eg, abdominal bloating or nausea/vomiting) that were indistinguishable from symptoms caused by radiation enteritis. Thus, patients with a known history of abdominopelvic radiation who present with symptoms consistent with radiation enteritis should also undergo an evaluation to rule out secondary neoplasms. Surgery is required for the treatment of secondary neoplasms. (See "Second malignancies after treatment of classic Hodgkin lymphoma".)
Malnutrition — Protracted lack of enteric feeding leads to malnutrition. In patients with radiation enteritis, malnutrition can occur with prolonged ileus or short bowel syndrome. Although most of these patients are nutritionally sustained with total parenteral nutrition (TPN), chronic TPN use can damage the liver. Thus, surgical resection or bypass of damaged intestinal segments (for ileus patients) or liver-small intestine transplantation (for patients with short bowel syndrome) can help patients wean off of daily total parenteral nutrition by resuming enteric feeding. (See "Management of the short bowel syndrome in adults".)
PREOPERATIVE PREPARATION — Surgery for radiation enteritis needs careful planning because of its complexity. Preoperative imaging needs to locate the lesion(s) as clearly as possible. Ureteral stents are often placed to protect the ureters, and the stoma site is marked to ensure that the stoma is placed outside the field of radiation. Collaboration among various surgical specialists (eg, general or colorectal surgeon, gynecologist, and urologist) may be required.
Preoperative localization of lesion(s)
Nonbleeding patients — Patients with gastrointestinal symptoms (eg, nausea, vomiting, obstipation, abdominal pain) and a history of abdominopelvic radiation usually first undergo abdominopelvic computed tomography (CT). CT can diagnose complications related to radiation enteritis, such as obstruction, perforation, or fistula. CT scanning with an enterography protocol to dilate the small bowel is preferred, if available.
If CT is not revealing, patients usually undergo barium imaging (barium gastrointestinal series or barium enema). A narrowed area of small bowel on barium imaging, particularly with proximal dilation, is indicative of an intestinal stricture. For patients who present with bowel obstruction, distended bowel loops caused by adhesions tend to be more angulated on barium imaging, while radiation-damaged bowel segments reveal stenosis or other mucosal abnormalities.
However, the quality of barium imaging is dependent upon both the skill and dedication of the radiologist as well as the patient's anatomy. Overlapping loops of adhesed small bowel are difficult to discern from one another in the pelvis where manipulation by pressure may be difficult to apply by the radiologist. Barium imaging can sometimes underestimate the number of strictures in patients who have had a prior abdominal operations [11].
For patients who require repeated imaging due to the progressive nature of their disease or recurrent symptoms, magnetic resonance (MR) enterography is preferred over CT because patients are not exposed to ionizing radiation with MR. MR enterography enables high-contrast resolution depiction of the location and cause of bowel obstruction through a combination of predictable luminal distension and multiplanar imaging capabilities. However, radiation enteritis appears nonspecific on MR enterography, usually as a focal abnormal loop of bowel within the radiation field. Further differentiation between adhesive and nonadhesive (eg, radiation-induced, infiltrative, or neoplastic) diseases may be difficult based upon imaging features alone. Thus, clinical correlation is required. Adhesive diseases typically cause mechanical bowel obstruction, whereas radiation enteritis causes mural thickening and edema of the bowel wall, which may be compounded by intestinal dysmotility [12].
The ability to accurately distinguish between radiation enteritis and recurrent cancer remains elusive. CT cannot distinguish radiation-induced injury from recurrent cancer with certainty (image 1) [13]. Positron emission tomography (PET) imaging can also yield false positive results of cancer in patients who develop radiation recall (an acute inflammatory reaction in a previous radiation field) to certain chemotherapeutic agents (eg, doxorubicin) [14]. In addition, PET cannot identify lesions smaller than 5 mm.
Bleeding patients — When catastrophic gastrointestinal bleeding is encountered, urgent endoscopy to establish a diagnosis is done with care and minimal insufflation because mucosal trauma secondary to the endoscopic procedure may exacerbate bleeding or even cause perforation. A randomized trial found no evidence that patients with radiation-induced chronic gastrointestinal symptoms, including rectal bleeding, benefited from hyperbaric oxygen therapy [15]. (See "Approach to acute upper gastrointestinal bleeding in adults", section on 'Upper endoscopy'.)
Capsule enteroscopy has been used to identify the source of bleeding from a suspected small intestinal source (picture 1) [16]. However, the risk of capsule impaction into a stricture led some investigators to identify a history of abdominal or pelvic irradiation as a relative contraindication to video capsule endoscopy in patients with occult gastrointestinal bleeding [17]. A novel dissolvable capsule (Given patency capsule) has been specifically designed to localize functional small bowel strictures [18]. (See "Wireless video capsule endoscopy".)
Alternatively, CT enterography can be used to localize the bleeding source [19]. It is sensitive and can show the bleeding lesion(s) in three dimensions. Although a nuclear medicine bleeding scan is sometimes used, it is less sensitive and provides no anatomical details, even when a bleeding source is identified.
Ureteral stenting — Injury to the ureters secondary to pelvic radiation is commonly assumed but rarely ascertained when there is nearby intestinal damage [20]. Although prophylactic stenting has not been shown to reduce ureteral injury, surgery for radiation enteritis is complex, and therefore preoperative ureteral stent placement is indicated to assist with the difficult dissection and to prevent or quickly identify ureteral injuries [21]. (See "Placement and management of indwelling ureteral stents", section on 'Prophylactic'.)
Stoma marking — When the operation requires creation of a stoma, it should be placed outside of the radiation field. Thus, the desired stoma location should be marked on the patient's skin outside of the field marked by indelible tattoos that are placed prior to radiation therapy. If a radiation field is not marked with tattoos, the potential stoma site should be designated with a metallic marker before the patient undergoes barium or CT imaging, which could reveal whether or not the stoma site is located near severely damaged intestine. (See "Overview of surgical ostomy for fecal diversion", section on 'Site selection and marking'.)
Multispecialty collaboration — Procedures for radiation enteritis are often performed jointly with other surgical specialists (eg, gynecologist, urologist). As an example, when a patient's rectum and bladder are both dysfunctional and stenotic, diversions of both the fecal and urinary stream are necessary. In addition, in order to construct a urinary conduit in this type of patient, an alternate segment of bowel must be identified as the ileum is likely also exposed to radiation as well.
Gynecologic (cervical, ovarian, and endometrial) cancers are the most frequently irradiated tumors, which makes gynecologic oncologic patients susceptible to radiation enteritis. Most of these patients have had a prior hysterectomy. If they need surgery for radiation enteritis, a vaginal surgical preparation as well as placement of a device within the vagina that permits easy localization can be helpful. A gynecologist can also assist if unexpected findings such as enterovaginal fistulae are encountered during the operation.
SURGICAL APPROACHES — Surgical approaches to radiation enteritis vary with each patient. In general, however, techniques such as bowel resection, intestinal bypass, and strictureplasty are used more often than techniques such as small intestine transplantation. Various surgical techniques are discussed below in the context of their most suitable target patient populations.
Adequate intestinal reserve: resection — If a patient has adequate intestinal reserve, resecting radiation-damaged small bowel is preferred because complications may reappear later at the same location if resection is not performed [22]. In one series of 49 patients who underwent surgery for radiation enteritis, 41 patients had bowel resection [22]. Although radiation-related illness recurred in 12 patients after surgery, the 5 and 10 year survival of this cohort remained high at 90 and 83 percent, respectively.
Resection of a bowel segment is also required in patients who have either intestinal perforation, secondary neoplasm, or fistulae caused by radiation enteritis.
The length of small intestine that is required for survival without intravenous nutrition or fluid support has been changed by the introduction of teduglutide, a human glucagon-like peptide-2 (GLP-2) [23,24]. Management of short bowel syndrome is discussed in another topic. (See "Management of the short bowel syndrome in adults".)
Limited intestinal reserve: Strictureplasty — Because strictureplasty conserves intestinal length, it is useful in treating patients with limited intestinal reserve who present with intestinal stricture(s). In those patients, if long segments of diseased bowel are resected or bypassed, significant nutritional or metabolic consequences would occur [25]. The techniques of strictureplasty are also used to treat patients with Crohn disease and are discussed elsewhere. (See "Surgical management of Crohn disease".)
Strictureplasty can be performed safely alone or in combination with other techniques, such as resection or bypass. In one small series, five patients with limited intestinal reserve because of previous surgery underwent reoperation for radiation enteritis [25]. Strictureplasty was performed alone in one patient and in combination with resection or bypass in the other four patients. All five patients were able to avoid total parenteral nutrition postoperatively at a mean follow-up of 42 months.
Short bowel syndrome can be caused by loss of intestine from either a single radical resection or multiple smaller resections required to treat radiation enteritis. If patients with short bowel syndrome need further surgery, an intestine-conserving technique such as strictureplasty should be employed. Alternatively, patients may undergo small bowel transplantation as a treatment of last resort. (See "Overview of intestinal and multivisceral transplantation".)
Massive adhesion: Intestinal bypass — Intestinal bypass is a suitable surgical technique to use in patients with massive adhesion, especially when they are too high risk to undergo a standard resectional operation [26].
In an early series, 11 of 17 patients who underwent surgery for radiation enteritis were treated with bypass in lieu of resection [27]. Successful outcomes were achieved in nine patients, with minimal morbidity and no operative deaths. Follow-up at 8 to 60 months showed no further sequelae of radiation injury or bacterial overgrowth in the blind loops. (See "Small intestinal bacterial overgrowth: Clinical manifestations and diagnosis", section on 'Jejunal aspirate culture'.)
Incurable disease: Palliative procedures — When faced with severe radiation enteritis refractory to all standard techniques described above, surgeons may use procedures aimed at palliating patient symptoms, such as abdominal pain or nausea, instead of curing the disease. Palliative procedures include decompression of the intestines with gastrostomy and jejunostomy tubes [28], stenting intestinal strictures with expanding metallic stents, as well as diverting the fecal stream with an ileostomy or colostomy [2]. (See "Assessment and management of nausea and vomiting in palliative care", section on 'Non-cancer conditions'.)
MORBIDITY AND MORTALITY — The reported morbidity and mortality rates following surgery for radiation enteritis are likely inaccurate because the published studies are small, nonstandardized, and retrospective. The reported mortality rates from available studies ranged from 0 to 35 percent [26,27,29].
The two major complications after surgical treatment of radiation enteritis are recurrence of the original symptoms, especially if the diseased segment of bowel is not completely removed for technical or patient reasons [22], and short bowel syndrome. Other surgical complications, such as anastomotic leak, wound infection, postoperative pancreatitis, and acute kidney injury, have also been reported but are not unique to surgery for radiation enteritis [25]. (See "Complications of abdominal surgical incisions".)
The development of insufficient intestinal reserve, or short bowel syndrome, can occur after repeated resectional surgeries. In one study of 48 patients who developed postresection short bowel syndrome, symptoms started in most patients within 12 months (range 1 to 234 months) after the initial operation; the remaining small bowel length ranged from 60 cm or less to 180 cm [29]. Parenteral nutrition was started in approximately 80 percent and continued long term in 60 percent of patients diagnosed with short bowel syndrome. A discussion of the management of short bowel syndrome can also be found elsewhere. (See "Management of the short bowel syndrome in adults".)
SUMMARY AND RECOMMENDATIONS
●Radiation to the abdomen or pelvis can damage intestinal structures, especially the ileum (radiation enteritis) and rectum (radiation proctitis). Although most early radiation injuries respond to supportive care alone, late effects of radiation often require surgical intervention. (See 'Introduction' above.)
●Complications from radiation enteritis that are refractory to medical therapy often require surgical treatment. These include obstruction, fistula, perforation, bleeding, neoplasm, and malnutrition. (See 'Indications for surgery' above.)
●In patients with adequate intestinal reserve, resecting radiation-damaged small bowel is preferred. Resection is also required in patients who have intestinal perforation, secondary neoplasm, or fistula caused by radiation enteritis. (See 'Adequate intestinal reserve: resection' above.)
●In patients with limited intestinal reserve (eg, short bowel syndrome) who present with intestinal strictures, a strictureplasty is preferred because it conserves intestinal length. (See 'Limited intestinal reserve: Strictureplasty' above.)
●In patients with massive adhesions, intestinal bypass is a suitable surgical technique to use, especially when a patient cannot tolerate a standard resectional procedure. (See 'Massive adhesion: Intestinal bypass' above.)
●In patients with severe radiation enteritis refractory to all standard techniques described above, surgeons may use procedures aimed at palliating patient symptoms (eg, feeding tube, stent, ostomy), rather than curing the disease. (See 'Incurable disease: Palliative procedures' above.)
●Insufficient intestinal reserve, or short bowel syndrome, can occur after repeated resectional surgeries for radiation enteritis. (See 'Morbidity and Mortality' above.)
