This article is more than 5 years old. Information may no longer be current.
Management strategies for inoperable malignant bowel obstruction
Click Here to Manage Email Alerts
Malignant bowel obstruction is an unfortunate but common complication of cancer. Whereas some patients may initially present with their cancer as a bowel obstruction, most patients with malignant bowel obstruction have had prior therapy and often have advanced disease. The most common solid tumor to present with malignant bowel obstruction at any stage is ovarian carcinoma, at as high as 20% to 50%; colorectal cancer follows, with rates between 10% and 28%.
However, virtually any type of solid tumor can cause malignant bowel obstruction (MBO) with metastasis to the abdomen. Multiple reviews of MBO have noted a range of recommendations on the best strategies for treatment, reflecting the heterogeneity of MBO and the few randomized controlled studies; this article, although focusing primarily on medical management, is based on both recent surgical and medical reviews.
Three paths to management
The three primary approaches to MBO management are surgical, interventional and medical. In terms of surgery, resection and reanastamosis are appropriate for those patients whose disease is amenable to complete resection. For those patients whose tumor cannot be completely resected, bypass or stoma creation can be performed. A venting gastrostomy tube can be placed for those patients who have multiple points of obstruction not amenable to other surgical intervention. These options all depend on the overall goals of care for a particular patient and patient-specific characteristics determining if they are surgical candidates.
|
|
Although these procedures are often for palliative purposes, poorer outcomes are associated with the following factors: age, cachexia and poor nutritional status, poor functional status and the presence of ascites. An interventional approach may be considered for those patients who favor a less invasive approach to surgery and involves endoscopic stent placement across a single obstruction. Colonic stenting tends to have more success than stenting for more proximal obstructions, but both are seeing increasing use. Stenting may also offer a bridge to surgery. Venting gastrostomy tubes can also be placed via interventional techniques, should an open approach be too risky.
For the many patients who are not candidates for surgery or endoscopic stent placement, medical management can bring significant symptom relief. The overall approach involves immediate decompression and fluid resuscitation, treatment of associated pain and nausea or vomiting, and reduction of intraluminal secretions. This medical management is not exclusive to patients who aren’t surgical or interventional candidates and is usually incorporated into the initial management of all MBO patients before interventional or surgical procedures.
Initial decompression usually involves nasogastric tube placement alongside in vitro fertilization hydration and electrolyte repletion. The volume of fluids should be given cautiously, to avoid increasing intestinal secretions and worsening symptoms. Although nasogastric tubes are considered mainstays in the initial treatment of MBO, they usually do not relieve symptoms completely, so medications are required.
Dealing with pain
The pain associated with MBO is often described as intense, crampy pain. This description may vary, based on the location of the obstruction; more proximal obstructions result in a crampy pain that occurs in short intervals vs. large bowel obstructions that cause less intense pain, although this is primarily based on clinical experience.
Managing this pain acutely takes a multi-pronged approach. IV opioids are primary therapy for pain in this setting; oral medications are usually not tolerated. Typically, the IV opioid choices include morphine, as well as dilaudid and fentanyl as an alternative (particularly in the presence of renal and hepatic dysfunction). Antispasmodics (ie, anticholinergic agents) also help to decrease the continued peristalsis against an obstruction and also help decrease gastrointestinal secretions. These include scopolamine and glycopyrrolate; of note, glycopyrrolate has fewer of the troublesome side effects in this class of medications, as it does not readily cross the blood-brain barrier.
For the nausea and vomiting, the dopamine antagonists such as prochlorperazine and haloperidol are considered preferred agents. Recently, octreotide, a somatostatin analogue, has become a primary therapy in the management of MBO for its multiple effects in breaking the vicious cycle of distension, increased gastrointestinal secretions and more distension. It modulates and inhibits gastrointestinal hormones, decreases motility and decreases splanchnic blood flow. Its antisecretory effects help decrease secretions and increases intestinal absorption as well. Side effects are minimal, the most common being dry mouth. A starting dose of octreotide for MBO would be 200 mcg to 600 mcg daily, which can be divided into boluses or given as a continuous infusion. The dose can be titrated up based on response every 24 hours, and there is also a depot form that can be given every 4 weeks for longer-term management.
Corticosteroids have also been used in primary medical therapy of MBO, although they are not as well studied as other treatments. They are thought to help reduce tumor-related inflammation and associated edema and can improve both the pain and associated nausea. Because of their profound side effects, corticosteroids should be limited to short-term use.
Stephanie Harman, MD is a Palliative Care Physician at Stanford University Medical Center and Director of its Inpatient Palliative Care service. Disclosure: Dr. Harman reports no relevant financial disclosures.
For more information:
- DeBernardo R. Curr Oncol Rep. 2009;11:287-292.
- Roeland E. Curr Oncol Rep. 2009;11:298-303.