Malignant bowel obstruction: Individualized treatment near the end of life
ABSTRACTMalignant bowel obstruction requires a highly individualized approach, tailored to the patient’s medical condition, prognosis, and goals of care. Surgery should not be routinely done. Less-invasive approaches such as gastric and colonic stenting are useful.
KEY POINTS
- Combinations of analgesics, antisecretory drugs, and antiemetics can provide acceptable symptom relief.
- A venting gastrostomy should be considered if drug therapy fails to reduce nausea and vomiting to an acceptable level.
- A nasogastric tube should be used only as a temporizing measure, until symptoms are controlled medically or a venting gastrostomy is placed.
- Total parenteral nutrition is beneficial only in patients with intermediate life expectancy who may otherwise die of starvation rather than the cancer itself.
Is enteroclysis better than barium swallow?
Enteroclysis, ie, injecting radiographic contrast into the bowel via a nasoduodenal tube, has some advantages over the barium swallow technique for detecting partial small-bowel obstruction, since it bypasses the stomach and allows for therapeutic decompression as well as direct visualization of the area of concern.17,18 Enteroclysis radiography objectively gauges severity of intestinal obstruction and bowel wall distensibility, which is an advantage over other imaging studies. Its sensitivity is 100% and specificity 88% in experienced hands.17 Enteroclysis studies also detect nonobstructing intraluminal tumors when computed tomography (CT) is not diagnostic.17,18,21
The drawbacks to enteroclysis are that it is technically difficult to perform and that few radiologists are trained in it.
When is CT useful?
CT is the primary imaging study for patients with obstructive symptoms and a history of abdominal malignancy or a palpable abdominal mass17,20,22,23 (Figure 1). It has a specificity of 100% and a sensitivity of 94%. It plays a major role in decision-making regarding surgery, endoscopy, or palliative interventions,7,19 as it locates the obstruction and differentiates benign from malignant causes with a fair degree of precision.22
CT findings in malignant bowel obstruction may include:
- A mass at the site of obstruction or within the original surgical field
- Lymphadenopathy
- Abrupt transitions in luminal diameter or irregular thickening of the bowel wall at the site or sites of obstruction.7
SURGERY: A DIFFICULT DECISION
Is the patient fit for surgery?
Surgery for malignant bowel obstruction should not be done in patients who have advanced malignancies with bulky intra-abdominal metastases or cancer that has spread outside the abdominal cavity without taking into account treatment options for the cancer, the patient’s nutritional status, and the goals of care.
The role of abdominal surgery (debulking, resection, or bypass) in advanced cancer remains unclear and controversial.24 From 42% to 80% of patients report that symptoms improve after surgery, but recurrent obstruction occurs in 10% to 50%.10 Even in patients with low tumor bulk and good nutritional status, 30-day mortality rates range from 5% to 40%, and complication rates range from 9% to 90%.3,4,6,7,10,14
Outcomes after surgery depend on patient selection criteria perhaps as much as on the surgeon’s experience and skill. Patients with more advanced cancer who have had multiple surgical procedures and those with cancer that does not respond to chemotherapy and radiation present the greatest challenge to surgeons.23
What is the benefit of surgery?
Reports of palliative surgery have included information about 60-day survival rates after the operation, but a number of factors may be more meaningful in this context, such as postoperative symptoms, the patient’s overall wellbeing, how the original symptoms respond to the surgery, complications, and length of hospitalization.14 The paucity of published, validated, patient-related outcome data on which to gauge the value of surgery and the lack of a standard definition of “benefit” further confuse the objective determination of whether these patients benefit from surgery.
In a cohort with advanced ovarian cancer and bowel obstruction, surgery was detrimental to survival and quality of life for all subgroups, and most patients died in the hospital.6
The risk of surgery for malignant bowel obstruction is presumably higher than for abdominal surgery for other indications, since many of the patients are debilitated from their cancer and chemotherapy, and many are malnourished.23 Even when taking into account a potential selection bias in favor of surgery, several studies have reported no significant difference in 30-day mortality rates or median survival between operative and nonoperative groups.2,12 Neither the type of obstruction nor the extent of the surgery influenced outcomes. Surgical outcomes are best in patients with a benign cause of obstruction; little benefit is seen in operating on those with abdominal carcinomatosis.12
Nevertheless, surgery is beneficial in a select few. For patients with a good performance status, slowly progressive cancer, and an expected survival of more than 6 months, surgical bypass or resection is preferred.7,12,25 The challenge is to identify these surgical candidates, taking into account prognostic factors such as nutritional status, tumor burden, performance status, presence of ascites, advanced age, extensive prior chemotherapy or radiotherapy, and diffuse carcinomatosis.3,10,12,20,23
Is surgery consistent with the goals of care?
Crucial to decision-making are the goals of care. Since palliative surgery carries a low level of evidence for benefit in terms of quality of life and survival, time should be set aside to thoroughly review the patient’s medical condition, to explore options, and to clarify expectations and goals of care.3,10 Family members should be invited to be present during these discussions and to be involved in the decision-making process.
WHAT IS THE BENEFIT OF GASTRIC OR COLONIC STENTING?
Endoscopic procedures are alternatives to surgery and offer a palliative option in malignant bowel obstruction. Endoscopic procedures are associated with a shorter hospital stay and quicker recovery than after laparotomy.9,26–30 In certain situations, stenting serves as a bridge to surgery, allowing time to mitigate comorbid conditions, to enhance nutrition, and to complete staging, while relieving symptoms.27–29,31,32 Definitive surgery can be done as a single-stage procedure without a diverting enterostomy.
Self-expanding metal stents for gastric outlet, small-bowel, and colonic obstructions are an option in patients who have incurable metastatic disease who are unfit for surgery, in patients with a single point of obstruction or locally extensive disease, or in patients who do not want to undergo laparotomy.28–30
Technical and clinical success rates for colorectal stenting are high (88% to 93%).26,27 Stenting is more successful for left-sided colonic obstructions than for proximal colonic obstructions. Even for patients with extracolonic malignancies such as ovarian cancer, the technical success rate of colorectal stenting is 87%.26 However, patients with unrecognized peritoneal carcinomatosis or multifocal bowel obstruction are less likely to have symptomatic relief even after successful stenting.6,9
