Colorectal cancer (CRC) is the second most common cause of cancer-related mortality, resulting in approximately 16,000 deaths each year. It will affect one in 18 people in the UK and as such, is the third most common cancer.
Although there have been vast improvements in surgical oncological techniques and additions to adjuvant therapeutics continue, the UK lags behind other European countries in cancer survival.
Prevention remains the best form of cure, but almost 50% of CRC presents in an advanced form, with early stage cancer remaining in the minority despite current screening programmes.
CRC lends itself well to screening because most of these cancers develop from benign colorectal polyps, which are easily detected and removed (polypectomy) endoscopically. Polypectomy within a screening programme has been shown to reduce the incidence of CRC by 75-90%.
The NHS Bowel Cancer Screening Programme (NHSBCSP)1 has been in place across England for more than five years for people aged 60-75.
Eligible members of the public receive a faecal occult blood (FOBT) kit for completion at home, which detects microscopic amounts of blood within the faeces. The completed kit is posted to the local screening hub for analysis.
Patients with a positive FOBT are then invited for colonoscopy by a nationally accredited screening colonoscopist.
The aim of colonoscopy is not only to detect cancers, but also to remove the precursor polyps, thereby reducing the incidence and mortality of CRC.
The FOBT test is repeated every two years and current evidence suggests this form of screening reduces the mortality of CRC by 16%.
Bowel scope screening
Although colonoscopy is well tolerated by most patients, it is an invasive procedure with associated rare but significant complications (for example, perforation rate of one in 1,500 for diagnostic colonoscopies, and haemorrhage). It is also an expensive procedure and often requires IV sedation.
It is known that most CRC occurs in the left colon, within reach of flexible sigmoidoscopy. In 2010, a large RCT demonstrated that one-off flexible sigmoidoscopy at the age of 55 reduces the incidence of CRC by 33% and mortality by 43%.2 This research resulted in the NHS Bowel Scope Screening Programme.3
The DH has committed to investing £60m to incorporate flexible sigmoidoscopy into the current screening programme and aims to make bowel scope screening (BSS) available to all 55-year-olds in England by 2016.
In six pilot areas, patients have already been invited for BSS around the time of their 55th birthday and endoscopies will be performed in centres of accepted endoscopic excellence (see box).
|Pilot areas for BSS|
What BSS involves
Invitations are sent to eligible patients eight weeks before their proposed appointment and once confirmed, a phosphate enema is posted to them, to be self-administered an hour before leaving home to travel to the screening hub. Patients are also given a helpline number in case they have any concerns.
Patients are offered nitrous oxide and oxygen, but not IV sedation, for the endoscopy and the colon is examined as far as comfort allows (usually into the descending colon).
Small polyps <10mm in size are removed during the procedure, although most patients will have a normal test and be discharged with reassurance.
Pilot data suggest about 5% of patients will be referred for colonoscopy because of the type or number of polyps found and one in 300 will be found to have CRC already.
BSS is an exciting new tool in our quest to reduce the impact of this common cancer and although there are significant challenges ahead in its successful implementation, any further potential reduction in the incidence and mortality of CRC is to be welcomed.
- Mr Wilson is consultant laparoscopic colorectal and general surgeon at The London Clinic and Whittington Health NHS Trust
1.NHS Bowel Cancer Screening Programme www.cancerscreening.nhs.uk/bowel/
2. Atkin WS, Edwards R, Kralj-Hans I et al. Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial. Lancet 2010; 375(9726): 1624-33.
3. NHS Bowel Scope Screening Programme www.cancerscreening.nhs.uk/bowel/bowel-scope-screening.html