Background
Advanced cancer causes a range of complex problems for patients. In gynaecological (for example ovarian and womb) and gastrointestinal (for example colon or bowel) cancers, the bowel can become blocked or obstructed by the original tumour, metastatic deposits or due to the side effects of previous treatments. The decision to operate on patients with bowel obstruction who are already very unwell because of their advanced cancer is difficult. Often, these people develop bowel obstruction as a sign that the cancer is progressing and they are in the process of dying. When the bowel obstructs in this situation, surgery might be useful for some patients, it might make no difference to how long the patient has to live, or it might make the situation worse due to the complications of surgery. When time is short, managing symptoms and maximising comfort for the patient is the priority. Different surgical teams adopt different approaches. We wanted to establish the evidence for the benefit and harm of surgery in these situations and therefore help patients and doctors make good decisions.
Key findings and quality of the evidence
We first looked at the evidence in 2000 and this is an update of the original review. In total we found 43 studies examining 4265 people. We looked at adults with advanced gynaecological or gastrointestinal cancer who developed bowel obstruction and had either surgical or non-surgical treatment. The studies we found were of low quality and measured success and benefit in different ways. It was therefore not possible to compare these studies and conclude whether surgery was of benefit or harm in this situation. Research in this area is problematic and the type of study needed to answer this question would be very difficult to conduct.
The role of surgery in malignant bowel obstruction needs careful evaluation, using validated outcome measures of symptom control and quality of life scores. Further information could include re-obstruction rates together with the morbidity associated with the various surgical procedures.
Currently, bowel obstruction is managed empirically and there are marked variations in clinical practice by different units. In order to compare outcomes in malignant bowel obstruction, there needs to be a greater degree of standardisation of management.
Since the last version of this review none of the new included studies have provided additional information to change the conclusions.
This is an update of the original Cochrane review published in Issue 4, 2000. Intestinal obstruction commonly occurs in progressive advanced gynaecological and gastrointestinal cancers. Management of these patients is difficult due to the patients' deteriorating mobility and function (performance status), the lack of further chemotherapeutic options, and the high mortality and morbidity associated with palliative surgery. There are marked variations in clinical practice concerning surgery in these patients between different countries, gynaecological oncology units and general hospitals, as well as referral patterns from oncologists under whom these patients are often admitted.
To assess the efficacy of surgery for intestinal obstruction due to advanced gynaecological and gastrointestinal cancer.
We searched the following databases for the original review in 2000 and again for this update in June 2015: CENTRAL (2015, Issue 6); MEDLINE (OVID June week 1 2015); and EMBASE (OVID week 24, 2015).
We also searched relevant journals, bibliographic databases, conference proceedings, reference lists, grey literature and the world wide web for the original review in 2000; we also used personal contact. This searching of other resources yielded very few additional studies. The Cochrane Pain, Palliative and Supportive Care Review Group no longer routinely handsearch journals. For these reasons, we did not repeat the searching of other resources for the June 2015 update.
As the review concentrates on the 'best evidence' available for the role of surgery in malignant bowel obstruction in known advanced gynaecological and gastrointestinal cancer we kept the inclusion criteria broad (including both prospective and retrospective studies) so as to include all studies relevant to the question. We sought published trials reporting on the effects of surgery for resolving symptoms in malignant bowel obstruction for adult patients with known advanced gynaecological and gastrointestinal cancer.
We used data extraction forms to collect data from the studies included in the review. Two review authors extracted the data independently to reduce error. Owing to concerns about the risk of bias we decided not to conduct a meta-analysis of data and we have presented a narrative description of the study results. We planned to resolve disagreements by discussion with the third review author.
In total we have identified 43 studies examining 4265 participants. The original review included 938 patients from 25 studies. The updated search identified an additional 18 studies with a combined total of 3327 participants between 1997 and June 2015. The results of these studies did not change the conclusions of the original review.
No firm conclusions can be drawn from the many retrospective case series so the role of surgery in malignant bowel obstruction remains controversial. Clinical resolution varies from 26.7% to over 68%, though it is often unclear how this is defined. Despite being an inadequate proxy for symptom resolution or quality of life, the ability to feed orally was a popular outcome measure, with success rates ranging from 30% to 100%. Rates of re-obstruction varied, ranging from 0% to 63%, though time to re-obstruction was often not included. Postoperative morbidity and mortality also varied widely, although again the definition of both of these surgical outcomes differed between many of the papers. There were no data available for quality of life. The reporting of adverse effects was variable and this has been described where available. Where discussed, surgical procedures varied considerably and outcomes were not reported by specific intervention. Using the 'Risk of bias' assessment tool, most included studies were at high risk of bias for most domains.