Dr Afsana Elanko
Director of Education, British Association of Surgical Oncology (BASO ~ The Association for Cancer Surgery)
Mr Jim Khan
Consultant Colorectal Surgeon & Clinical Director, Portsmouth Hospitals NHS Trust; Trustee BASO~ACS; and Honorary associate Professor Anglia Ruskin University Cambridge
Bowel cancer is the fourth most common cancer in the UK, with 42,000 cases diagnosed per year. It is treatable and curable if diagnosed early, but only 10-15% present early enough.
The five year survival for colon and rectal cancer remains at 65% and 67% respectively. Over 20% of cases present very late with locally advanced or metastatic disease making cure less likely. The key challenge for surgeons remains the early diagnosis and staging, followed by precision surgery to ensure complete cancer resection.
Signs of early bowel cancer
Early colorectal cancer is asymptomatic and can only be detected with screening. Commonly used screening tests are feacal occult blood (FOB) test and Faecal Immunochemical Test (FIT) with varying degrees of sensitivity and specificity.
In FOB testing, three stool samples are needed and the central screening hub for the region analyses the results and, if positive, the patient is called for colonoscopy. Out of 10 patients undergoing colonoscopy for this reason, only one or two may have a colorectal cancer. FIT is far more specific for human blood in stool and only one test is needed and those who score positive are invited for endoscopic screening.
Endoscopy provides the best assessment and diagnosis of colonic polyps and cancers. A recent pilot is investigating the role of a one-stop flexi-scope bowel cancer screening with a flexible Sigmoidoscopy, which can rule out over 70% of colorectal cancers.
New developments that may improve prognosis
Robotic colorectal cancer surgery has shown improved outcomes for patients, as precision surgery with enhanced views and endo wrist instrumentation can lead to better cancer resection and improved survival. This also has the potential to reduce the need for chemotherapy and radiotherapy in a select group of patients.
With the recent advances in digital surgery, there is huge potential for intra-operative navigational tools that can enormously help the surgeon to ensure complete cancer removal. Currently, this type of surgery is more expensive, has limited availability of experts; but the situation is likely to change over the next five years.
What about chemotherapy and Immunotherapy?
Chemotherapy can improve survival in colorectal cancer when used for advanced cancers or those with worse prognosis. Currently, a combination of different chemotherapy agents for a period of three to six months is used. Research continues to find the correct combination, the ideal duration of treatment and the selection of patients who will benefit the most from chemotherapy.
Immunotherapy is also a newer development showing promising results in various cancers and its role in the management of advanced colorectal cancers is currently under review. Some examples include:
Immune checkpoint inhibitors – Can be used for patients whose cancer cells have tested positive for specific gene changes, e.g. changes in one of the mismatch repair genes or high level of microsatellite instability. Usually given to patients whose cancer is still growing post chemotherapy, but can be used in patients whose cancer is not resectable, has reoccurred post treatment or metastasized.
PD-1 Inhibitors – These drugs help to boost the immune system against cancer cells by targeting a protein (PD-1) on the T cells that normally prevents these cells from attacking other cells in the body.
CTLA-4 Inhibitor – Also works by boosting the immune system, but it blocks a different protein on the T cells