Prospective comparative effectiveness trial for malignant bowel obstruction: SWOG S1316

Malignant bowel obstruction (MBO) is a relatively common problem in patients with advanced intra-abdominal cancers. It is most often seen in patients with ovarian and colorectal cancers, but it can also occur with many other types of cancer. MBO is rarely an emergent problem requiring immediate intervention, and surgical teams usually have time to consider optimal treatment approaches.

No defined algorithm of care has been created for most patients with MBO. Many patients who present with an MBO are surgical candidates, and for some, an operation may be deemed the best option. However, in many instances the patient care team may decide to avoid an operation.

The Prospective Comparative Effectiveness Trial for Malignant Bowel Obstruction trial (S1316) was developed to address this clinical conundrum. The study is funded in collaboration with the Agency for Healthcare Research and Quality (AHRQ R01 HS021491) and SWOG (formerly known as the Southwest Oncology Group) through the National Cancer Institute Community Oncology Research Program Research Base grant 5UG1CA189974-01 to provide evidence to identify which algorithm of care may be optimal for patients with MBO.

Study aims

The aim of S1316 is to assess the quality of life (QOL) outcome of “good days,” defined as the number of days alive and outside of the hospital within the first 91 days (13 weeks) after registration, for patients with MBO who receive surgical intervention in comparison with patients who undergo nonsurgical intervention. Research questions include:

  • Are there differences in health-related QOL outcomes for patients with MBO who receive surgical intervention as compared with nonsurgical intervention?
  • Are there clinical factors that predict better health-related QOL outcomes for patients with MBO who receive surgical or nonsurgical intervention?

Study approach

This study uses a mixed approach, meaning that a randomized arm will be augmented by an observational arm (see Figure 1). Notably, all patients must be “randomizable”; that is, they all must be surgical candidates and there must be equipoise as determined by the surgical team for both surgical versus nonsurgical treatment. For surgery, the lead surgeon in the operating room (OR) makes the decision. For the nonsurgical arm, nonoperational approaches, such as the use of percutaneous endoscopic gastrostomy tubes, are allowed.

In this trial, the nonsurgical arm mandates a trial of a somatostatin analog because of existing evidence of its benefit for MBO and because no evidence exists that points to detriment if the patient should later require surgical intervention. Patients will be accrued either to the randomized arm or the non-randomized/observation arm after they are seen by a surgical team. For example, if the team believes the patient would benefit from a week of parenteral nutrition to make them eligible for the OR, the patient may be registered at that time (see Figure 1).

Figure 1. SWOG S1316 Schema

Figure 1. SWOG S1316 Schema

Eligibility criteria

As a surgical trial, one of the most important criteria is that the patient must be a candidate for surgery, meaning that not only is the patient likely to survive an operation, but also that the team feels an operation is indicated. In addition, the team must agree that either treatment approach, operative or nonoperative, is reasonable. This agreement does not necessarily mean that the operating team is without bias, but rather that it is open to alternatives.

Patients requiring an emergency operation are not eligible to participate in this trial. Other eligibility criteria include the following:

  • MBO due to intra-abdominal primary cancer with incurable disease
  • Clinical evidence of a small bowel obstruction beyond the ligament of Treitz with supporting imaging evidence
  • Zubrod performance status of 0–2 one week before admission
  • The ability to complete questionnaires in English or Spanish

Patients will be contacted weekly for 13 weeks, and then monthly for up to one year.


The primary outcome is a composite measure of “good days,” defined previously. Multiple secondary endpoints will be measured, including the ability to eat (as measured by serial diet recalls), health-related QOL, morbidity and mortality, and survival.

Study status

This study was initially limited to a few sites, but to augment accrual, the study has been opened to other sites across the U.S. Potential sites must have dedicated surgical teams with interest in this issue, including multiple surgical specialties, such as gynecologic oncology, surgical oncology, colorectal surgery, and general/acute care surgery. The study is open on the National Cancer Institute Cancer Trials Support Unit, so not all sites are mandated to be SWOG.

If you are interested in having your health care center become a site for this important surgical study, e-mail

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