Early detection of anastomotic leak after colorectal surgery
Bowel cancer is common in the UK. Over 2000 patients are diagnosed a year in Wales alone. Despite being a highly curable cancer, especially when caught early, 900 patients still die a year in Wales. Treatment usually involves surgery where the cancer is removed and the two ends of bowel are joined back together to restore normal function. However, joining the bowel back together carries a risk of a leak - rather like joining two pipes together in the kitchen and turning the water on.
A leak can occur in up to 1 in 5 patients in certain "high risk" situations. When this happens, bowel contents escape into the abdomen, making the patient very unwell and requiring emergency surgery to take down the join and create a stoma bag on the patient's tummy. This leads to a longer and more difficult recovery from the surgery, and may also delay additional cancer treatment.
Clinical staff watch carefully after an operation for certain signs that may indicate a leak from the bowel. These signs can be subtle and difficult to pick up, and a leak is often not detected until 3-5 days after the operation. By this time it can be challenging to salvage the join and the patient may become very unwell. This can result in more complications and even death after emergency surgery.
Our research aims to validate a new diagnostic test that can detect a leak earlier and more accurately. If introduced in clinical practice, such a test would improve the management of patients after surgery, help improve outcomes and quality of life for patients, and ultimately save costs for the NHS. In particular, our research may help the early detection of leaks before patients develop symptoms, allowing their early management and salvage of the join to prevent long-term and permanent stoma bag formation and aid a faster recovery.
Our research is based on the detection of biomarkers in the fluid draining from the site of the operation. We will measure the concentrations of molecules that may be produced as a result of a bowel leak, and the type and number of different immune cells that respond. This allows us then to identify those markers that indicate the presence of a leak and that are clearly different from "normal" drain fluid without post-surgical complications.
Our recent pilot study in 42 patients in one hospital highlighted two biomarkers as particularly interesting for further testing. We now want to confirm these findings in a larger group of patients recruited from hospitals across the UK and beyond. This group will also include patients undergoing operations of their bowel for other reasons, such as inflammatory bowel disease. We do this because we believe the ideal test should be able to detect a leak not only in cancer patients but in all patients having part of their bowel removed.
The use of drains in bowel surgery to remove the wound fluid produced at the site of operation from the body is done selectively, according to the discretion of the surgical team. In fact, evidence suggests that drains may at least sometimes be unnecessary. An important part of our work wil l therefore include detailed discussions with clinicians, carers and patients into the acceptance of the use of drains. Shared decision making is critical, and any drain fluid-based diagnostic test will only be successfully embedded in clinical practice if patients are comfortable with the rationale of carrying a drain bag for several days after operation.