The decision-making process in advanced oncologic patients requires an individualized evaluation based on the extension of the neoplasm, the overall prognosis, the availability of specific cancer treatment options, the associated comorbidities, the performance status, and the specific treatment options available to the duly informed patient. Treatment options include surgery, endoscopic palliation (stent), digestive aspiration, and symptomatic palliative pharmacologic therapy.

The aim of surgery is to re-establish digestive function and should always be considered in patients in the initial stages of the disease, with a good performance status and a single level of occlusion. The surgical treatment of MBO comprises tumour resection, intestinal bypass, and stoma formation proximal to the level of stenosis. Studies involving a series of surgical cases of MBO have shown a 30-day mortality of 25 % (9–40 %), postsurgical morbidity of 50 % (9–90 %), a rate of re-obstruction of 48 % (39–57 %), and a median survival of seven months (2–12 months) [6, 7, 10, 12, 24–29]. Age, advanced disease, malnutrition, and poor performance status are considered factors for poor prognosis even in cases where surgery may technically be possible [6, 12, 16]. A study on patients with colon cancer undergoing surgery for MBO reported an increase in surgical mortality associated with age, with an OR of 1.85 for each 10-year interval of age above 65 years. Using the American Society of Anaesthesia (ASA) scale to measure deterioration of general status, surgical mortality increased in patients with a score ≥2, compared to those with a score <2 (odds ratio 3.3) [30]. Furthermore, surgical mortality is threefold greater in patients with poor nutritional status and hypoalbuminaemia. In ovarian cancer, the presence of ascites greater than 3,000 mL and palpable tumour masses are significant contributors to a poor surgical outcome [6, 10, 31]. Pelvic and abdominal radiotherapy prior to MBO is associated with a high rate of surgical complications and an increase in operative mortality in patients with gynaecological cancer, a fact that has not been fully confirmed in cancer of other etiologies [10, 32]. These findings on ascites and previous pelvic radiotherapy may be of relevance for other primary cancer sites although there is a lack of published evidence in this field.

Medical treatment prior to surgery for MBO is based on no oral intake, parenteral hydration, nasogastric aspiration, and antiemetic and analgesic drugs. The aims of these measures are to control the symptoms, re-establish the physiological balance of electrolytes, favour spontaneous resolution, and gain the time necessary to establish a diagnostic process to facilitate individualized surgical decisions. With these measures, adequate control of the symptoms can be achieved in 80 % of cases if low-residue diet and nasogastric aspiration are maintained. It is reasonable to assume that nasogastric aspiration at the onset of the obstruction may favour spontaneous resolution since it drastically reduces endoluminal pressure. However, long-term nasogastric aspiration is uncomfortable for the patient and has significant side effects (esophagitis, gastroesophageal reflux, nasal erosions, and bronchoaspiration). In a series of surgical cases, spontaneous resolution has been reported in 30 % of patients within a mean time of less than 8 days after diagnosis. For this reason, and considering the hypothesis that nasogastric aspiration may improve the rate of spontaneous resolution, there is no reason to maintain nasogastric aspiration for longer than 8 days, especially when adequate symptom control can be achieved with intensified palliative care treatment.

In summary, the following factors do limit the indication of surgery in MBO: advanced age, current or previous malnutrition or cachexia, peritoneal carcinomatosis, multiple levels of obstruction, palpable abdominal masses, refractory ascites, symptomatic extra-abdominal metastatic disease, poor performance status, renal or hepatic insufficiency, previous abdominal or pelvic radiotherapy, and lack of specific oncologic treatment options [3, 6, 12].

The use of stents has increased during recent years for the treatment of proximal small bowel as well as large bowel obstructions. The stent is formed by a network of metal filaments braided and assembled in a tube-like structure, which is capable of a radial self-expansion after placement in the area of an obstruction. The pressure exerted by the stent itself once deployed allows anchoring to the intestinal wall and prevents migration.

In the large bowel, their role is particularly useful in obstruction distal to the splenic flexure. Stent placement should be performed endoscopically or guided by fluoroscopy in interventional radiology. The full expansion of the stent may require several days after placement.

Successful insertion of a stent in colon cancer ranges from 80 to 100 % of the cases and improves symptoms in more than 75 % of the patients. The mean duration of colonic stent patency is 106 days (66–88 days). The most common complications of this technique are immediate or delayed perforation (4.5 %), migration (11 %), and obstruction (12 %) [33, 34]. Some studies show that the wall-covered stent provides a better long-term palliation because its cover prevents tumour growth into the lumen of the stent; the migration risk, however, appears to be greater. Recurrence of obstruction due to tumour growth through the mesh or endoluminal at the ends of the stent may require the placement of a second stent after reopening the lumen mechanically, with a laser (Nd:YAG laser) or with photodynamic therapy.

In summary, self-expanding metal stents can be considered a good option in patients with a single point of obstruction in whom palliative surgery has been ruled out or in those who do not want to undergo surgery. Endoscopic stents can also be used as a “bridge to surgery” where patients are being considered for cancer resection but require urgent resolution of bowel obstruction prior to definite or palliative surgery.

As mentioned previously, long-term aspiration using a nasogastric tube is uncomfortable and may produce severe secondary effects. The insertion of a percutaneous endoscopic gastrostomy (Venting-PEG) may be a highly effective and safe alternative for patients in whom surgery is ruled out and who require long-term nasogastric tube insertion. In MBO secondary to advanced ovarian cancer, the success of percutaneous endoscopic PEG placement is 94 % (94–98 %), which achieves adequate symptom control in 84 % of the patients for a mean duration of 70 days, even in patients presenting with peritoneal carcinomatosis, ascites, or gastric infiltration [35, 36]. These data on ovarian cancer can be applied to MBO due to peritoneal carcinomatosis of other primary origins.

In 1985, Baines et al demonstrated that pharmacologic treatment, specifically palliative treatment for inoperable MBO, may provide adequate symptomatic control with measures aimed at maintaining the maximum comfort possible [5]. Palliative treatment for MBO has the following objectives: control of nausea, vomiting, and pain, allowing minimum food intake, avoiding or withdrawing permanent nasogastric tubes, and favouring outpatient treatment. This treatment is based on the use of antiemetic, potent analgesic, glucocorticoid, and antisecretor drugs in combination with the most comfortable route of administration to allow its application within the homecare setting [2, 5, 6].

More than 80 % of patients with MBO present with continuous pain and severe colic [5, 6, 8, 9]. The administration of analgesics for the treatment of MBO should be adjusted to the analgesic scale of the World Health Organization (WHO), which has demonstrated an efficacy rate greater than 80 % in cancer patients [37–40]. According to the European Society of Palliative Care and the WHO, it is now accepted that the majority of available strong opioids are effective for the treatment of cancer pain (morphine, methadone, oxycodone, fentanyl, hydromorphone, etc.) [41]. Some authors have reported that oxycodone may be more effective than other opioids for visceral pain treatment given its action on the kappa-opioid receptors, although this has yet to be confirmed in controlled clinical studies [42]. A meta-analysis of five controlled clinical trials by Tassinari et al in 2009 confirmed that fentanyl is a potent opioid that produces less constipation as a secondary effect [43]. A recent descriptive analysis of MBO in advanced cancer shows that more than 60 % of the patients were treated with potent opioids prior to the occlusive episode and more than 80 % required these drugs for analgesia during the episode. In this study, no statistically significant differences were observed in the rate of spontaneous resolution under symptomatic treatment among patients treated with a potent opioid prior to or during the episode of MBO versus those who did not receive this type of drug [6]. The opioid dose should be titrated individually for adequate pain relief. The subcutaneous, intravenous, sublingual, or transdermal route for opioid administration should be used frequently because nausea and vomiting do not allow for oral administration.

Antiemetic treatment uses drugs from three pharmacological groups: anticholinergic, dopamine antagonists, and serotonin antagonists (5-HT3). The dopamine antagonists are divided into benzamides (metoclopramide), butyrophenones (haloperidol), and phenothiazines (chlorpromazine). Metoclopramide blocks the dopamine receptors (D2) at the central and peripheral level. Its action facilitates the release of acetylcholine and at high doses (120 mg/day) antagonizes the 5-HT3 receptors. The mixed, central, and peripheral actions result in an antiemetic and prokinetic digestive effect of metoclopramide. The usual metoclopramide doses range from 40 to 120 mg/day. Haloperidol and phenothiazines (chlorpromazine and levomepromazine) are neuroleptic drugs that block the dopamine receptors at the central level only. They have a potent antiemetic, but no prokinetic effect. Among these drugs, haloperidol is considered the best choice because it produces less somnolence and anticholinergic effects. Haloperidol doses range from 5 to 15 mg/day, which can be administered in divided doses subcutaneously or intravenously, or by continuous subcutaneous or intravenous infusion. Scopolamine and hyoscine butylbromide are anticholinergic drugs. The antiemetic effects result from blocking acetylcholine at the central and peripheral levels in association with a clear antisecretor effect. Hyoscine butylbromide doses range from 40 to 120 mg/day. The serotonin (5-HT3) receptor antagonists, such as ondansetron or granisetron, can be useful for emesis control in the treatment of MBO. A recent noncontrolled phase II study demonstrated an index greater than 80 % for the antiemetic control of MBO using granisetron (5-HT3 receptor antagonist), even in cases that have not responded to typical antiemetic treatment [8]. The ondansetron dose ranges from 12 to 24 mg/day, and the granisetron dose ranges from 1 to 3 mg/day. These drugs are usually well tolerated. Headache, dizziness, and constipation are the most commonly reported side effects associated with their use.

Glucocorticoids possess an antiemetic action, the mechanism of which is not well known, and an anti-inflammatory action that reduces peritumoural oedema. Therefore, most researchers recommend glucocorticoids in the palliative treatment of MBO. A meta-analysis of three controlled clinical trials published in 1999 demonstrates that the use of glucocorticoids, particularly dexamethasone at a dose ranging from 6 to 16 mg, collaborates with the antiemetic action and favours the spontaneous resolution of MBO in advanced gynaecological and digestive cancer. In this meta-analysis, the rate of spontaneous resolution was 62–68 % in patients treated with glucocorticoids compared to 33–57 % in those receiving placebo [32, 44, 45].

The objective of antisecretor drugs is to reduce intestinal hypersecretion and, secondarily, to improve nausea, vomiting, and pain. Anticholinergic drugs (scopolamine, hyoscine, and butylbromide) have traditionally been the antisecretor of choice. Octreotide, a somatostatin analogue, provides a more specific and prolonged antisecretor effect. The pharmacologic activity of octreotide is mediated by the inhibition of the secretion of vasoactive intestinal peptides. This pharmacologic activity reduces electrolyte retention in the intestinal lumen, as well as gastric secretions, intestinal motility, biliary flow, splanchnic hypervascularization, and intestinal parietal oedema. Furthermore, it increases the absorption of water and the production of intestinal mucous [46, 47]. Different studies on the effectiveness of octreotide at doses from 200 to 600 μg/day have shown a clear reduction in intestinal secretions, decreased need for nasogastric tubes, and a high grade of antiemetic and analgesic response with no relevant adverse effects [3, 6, 9, 48–52]. Two controlled clinical studies have compared the antiemetic, analgesic, and antisecretory efficacy of octreotide (300 μg/day) versus hyoscine butylbromide (60 mg/day) in the treatment of MBO. In both studies, the efficacy of octreotide was statistically greater in all the parameters of response (reduction in digestive hypersecretion and control of nausea and vomiting) [48–50]. A phase II study demonstrated that a long-acting formulation of octreotide (LAR Depot) in combination with corticosteroids is useful and safe for the treatment of MBO due to peritoneal carcinomatosis [53]. A recent review of the literature concludes that despite the limited number of controlled clinical trials, octreotide is the antisecretory agent of choice for the treatment of MBO based on the results from 15 consistent studies and the experience acquired from 20 years of its use [54]. Histamine-2 antagonists and proton pump inhibitors are useful for reducing gastric secretions. A recent meta-analysis confirmed that ranitidine is more effective than proton pump inhibitors as an antisecretory agent. Based on these data, the authors hypothesized that ranitidine would be useful as an adjuvant drug in antisecretory therapy for the treatment of MBO and suggested the development of specific research to confirm these findings [55, 56].