Colorectal cancer is a common cancer that is very treatable when diagnosed at an early stage. However, late-stage diagnoses have a poor prognosis and are more costly to treat. The use of flexible sigmoidoscopy as a screening tool can not only identify cancers at an earlier stage but can also remove precursor lesions, potentially leading to long-term protection.
Evidence on long-term protective benefits of flexible sigmoidoscopy screening
Before the UK Flexible Sigmoidoscopy Screening Trial (UKFSST), there was no scientific evidence on the long-term benefits of flexible sigmoidoscopy as a colorectal cancer screening method. The UKFSST provides conclusive evidence for screening programmes everywhere on the long-term effectiveness of a single flexible sigmoidoscopy examination for reducing incidence and mortality from colorectal cancer over a period of approximately 20 years.
The UKFSST is a unique resource able to provide vital information to help inform how colorectal cancer screening should be conducted in the UK and beyond. Previously, there was little data on the long-term benefits of flexible sigmoidoscopy. Now, however, the UKFSST can provide data on the efficiency of flexible sigmoidoscopy, the duration of effect, the number needed to screen to prevent one colorectal cancer diagnosis (important for cost-effectiveness analyses) and whether the effect is evident in subgroup analyses by gender, age and sub-site. In addition, the UKFSST forms the basis for many value-added prospective analyses.
Scientific evidence for NHS Bowel Cancer Screening Programme
The UKFSST was instrumental in providing data to support the implementation of flexible sigmoidoscopy in the NHS Bowel Cancer Screening Programme in England in 2013. Speaking at the introduction of flexible sigmoidoscopy into the screening programme, Harpal Kumar, Chief Executive of Cancer Research UK said of the UKFSST:
“Cancer Research UK does not often use the word ‘breakthrough’ but this is one of those rare occasions when I am going to. It is extremely rare to see the results of a clinical trial which are quite as compelling as this.
In January 2021, however, flexible sigmoidoscopy was withdrawn from the Bowel Cancer Screening Programme in England. Despite its proven long-lasting protective effect against lower colorectal cancer, a shortage of endoscopists to carry out the test meant that flexible sigmoidoscopy screening was never fully rolled out across the whole of England. This was further compounded by the COVID-19 epidemic and its disruption of endoscopy services, leading to flexible sigmoidoscopy as a screening method being officially stopped in England.
However, the publication of our latest findings in 2024 on the long-lasting protective effect of a once-only flexible sigmoidoscopy for colorectal cancer has led to a call for a reconsideration of flexible sigmoidoscopy for screening.