Management of Treatment-Related Intermittent Partial Small Bowel Obstruction: The Use of Octreotide
Article Outline
To the Editor:
We submit to you the following case and brief discussion intended to outline a possible role for the independent use of octreotide in the setting of cancer treatment-related intermittent bowel obstruction. In addition, and of great significance in the setting of cancer survivorship, we identify an innovative aspect to the symbiotic partnership between the fields of palliative care and oncology.
Case
At the age of 40 years, after having lived with severe endometriosis for many years, the patient underwent a total abdominal hysterectomy-bilateral salpingo-oophorectomy. During routine follow-up 14 years after the surgery, a large pelvic mass was discovered and subsequently determined to be a Grade 2 endometrioid adenocarcinoma of the vagina. It was hypothesized that the mass originated from an endometrioid nodule in the vagina, and a low anterior surgical resection was felt to be the most appropriate intervention. Postoperatively, the patient received 45 Gy in 25 fractions of radiation to the pelvis and 550 cGy in two fractions of high-dose-rate brachytherapy to the vaginal vault. Two years post-treatment, follow-up imaging studies reported no evidence of residual, recurrent, or active disease.
Two-and-a-half years after the end of her cancer treatment, the patient began to experience a cyclical pattern of abdominal symptoms, consisting of pain, distension, nausea, vomiting, and obstipation. On multiple occasions, symptom severity led to an emergency department visit, and on two occasions, within a six-month period, she required hospitalization. Imaging obtained during each admission confirmed a moderate-grade small bowel obstruction but no associated mass. This led to the opinion that postsurgical and/or postradiation adhesions were likely to be the underlying cause. During both admissions, the patient's symptoms resolved with conservative management alone, consisting of nasogastric (NG) tube placement/suction and intravenous hydration. Of note, her hospital stays were five days and two weeks in length. Follow-up colonoscopy was unremarkable; specifically, no sign of anastomotic stricture was found.
The cycle of symptoms the patient was experiencing progressively increased in both severity and frequency over the subsequent nine months. Under the guidance of a clinical nutrition specialist, major dietary changes proved to be of no benefit, and on a daily basis, she was able to take in only small amounts of a nutritional supplement. The patient had not eaten solid food for a year and had not been able to return to work. Nearly four years post-cancer treatment, magnetic resonance imaging of the abdomen and pelvis confirmed “subtle thickening of rectal wall likely from chronic changes of prior radiation treatment” and “neither evidence of obstruction nor of recurrent disease.” As a result, surgical intervention was considered the only possible long-term management strategy for her intermittent obstructive symptoms. As a final effort to explore medical management of her symptoms, and despite having cured disease, the patient's radiation oncologist referred her to palliative care for an assessment.
The patient was first seen by a palliative care specialist 11 months after her initial admission for bowel obstruction. The pattern of her symptoms was as follows: Day 1, severe diarrhea; Day 2, abdominal pain and distension with no passage of stool; Day 3, progressive increase in pain and distension; and Day 4, severe vomiting, which persisted for one to two days. The patient would remain symptom free for at most two days before the cycle began again.
Despite a lack of evidence for the efficacy of octreotide in the setting of nonmalignant bowel obstruction (NMBO), it was felt that the clear evidence for its efficacy in the malignant bowel obstruction (MBO) population warranted a trial for this profoundly symptomatic patient. She was instructed and taught to subcutaneously administer 300 μg of octreotide three times daily at the first sign of symptom onset. Given the pattern of her symptoms, it was agreed that she would continue the injections for a five-day course.
Within four weeks, the patient had improved dramatically, having experienced an onset of only two symptom cycles, each significantly less severe than previous. Four months after the introduction of octreotide and with minor dose adjustments, she established the routine of a five-day course of octreotide 200 μg twice daily, initiated at symptom onset. This is required approximately once per month, and the patient remains symptom free in the interim three weeks. While taking the octreotide, no side effects are experienced, and with this intervention, she is now able to eat a full diet, has gained 8 pounds, and has returned to work.
Comment
Regardless of the underlying etiology, an obstruction of the bowel results in accumulation of ingested fluids, digestive secretions, and intestinal gas. In response to the subsequent luminal distension, the secretion of several gastrointestinal hormones mediates a further increase in the accumulation of water and electrolytes.1 Ongoing peristaltic activity leads to a cycle of distension-secretion-motor activity and a self-perpetuating worsening of the clinical condition.
In 1992, case reports addressing medical management of MBO first suggested a possible role for octreotide.2 Clear evidence of the use of this medication now exists in the MBO setting, as it is has been found to improve both survival and symptom management of patients with advanced cancer.3, 4 Administration of octreotide, a synthetic analog of somatostatin, results in a reduction of gastric and intestinal secretions, a slowing of intestinal motility, and a reduction of splanchnic blood flow.5 At the intracellular level, octreotide acts at the interstitial epithelium to decrease secretion of water, sodium, and chloride, and improve both ion and water absorption.6 These effects may be attributed to the inhibition of vasoactive intestinal peptide, a gastrointestinal hormone known to have increased levels in patients with any form of bowel obstruction.7 Peak plasma concentration of octreotide occurs 30 minutes after administration, and its duration of action can be up to 12 hours. The medication is particularly well tolerated and causes rare side effects, such as diarrhea, nausea, and biliary sludge.8 Long-acting formulations are now available and administered as monthly intramuscular injections.9
In contrast to MBO, a few reports have addressed the efficacy of medical interventions in the management of NMBO. As outlined in a recently published set of management guidelines, only water-soluble contrast has been found to have Level 2 evidence for its role in improving the bowel function of NMBO patients.10 No other medical therapy is addressed in the report. Only one randomized controlled trial has examined octreotide and its use in the setting of NMBO management. Comparing a control group of patients receiving conservative therapy alone (NG suction and fluid replacement) with a treatment group receiving a combination of both water-soluble contrast and octreotide, Zhang et al. reported the time to resolution of obstructive symptoms to be significantly less in the treatment group.11 Given its mechanism of action, the authors propose octreotide as being responsible for the rapid effect.
To our knowledge, this is the first case report suggesting a possible independent role for octreotide in the prophylaxis and/or management of post-cancer treatment/adhesion-related intermittent partial bowel obstruction. Given the patient population, most of the studies examining the medical and symptom management of MBO patients are found in the palliative care literature. As targeted cancer therapies improve, complex clinical syndromes related to survivorship are becoming increasingly common. In addition to identifying a possible independent role for octreotide in the management of NMBO, this case also highlights the unique role palliative care expertise may play in supporting the management of complex clinical conditions associated with cancer survivorship.
References
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- . Octreotide in the management of inoperable gastrointestinal obstruction in terminal cancer patients. J Pain Symptom Manage. 1992;7:496–498
- . A randomised trial of octreotide vs best supportive care only in advanced gastrointestinal cancer patients refractory to chemotherapy. Br J Cancer. 1995;71:97–101
- . Management of malignant bowel obstruction. Eur J Cancer. 2008;44:1105–1115
- . Vascular responsiveness in obstructed gut. Dis Colon Rectum. 1991;34:229–235
- . Importance of vasoactive intestinal peptide and somatostatin for fluid losses in small-bowel obstruction. Scand J Gastroenterol. 1995;30:464–469
- Does vasoactive intestinal polypeptide mediate the pathophysiology of bowel obstruction?. Am J Surg. 1989;157:109–115
- . Somatostatin. N Engl J Med. 1983;309:1495–1501
- Long-acting octreotide for the treatment and symptomatic relief of bowel obstruction in advanced ovarian cancer. J Pain Symptom Manage. 2005;30:563–569
- . Guidelines for management of small bowel obstruction. J Trauma. 2008;64:1651–1664
- Randomised clinical trial investigating the effects of combined administration of octreotide and methylglucamine diatrizoate in the older persons with adhesive small bowel obstruction. Dig Liver Dis. 2006;38:188–194
PII: S0885-3924(10)00084-9
doi:10.1016/j.jpainsymman.2009.11.309
© 2010 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved.
