Long-term effects of once-only flexible sigmoidoscopy screening on colorectal cancer incidence and mortality: 21-year follow-up of the UK Flexible Sigmoidoscopy Screening randomised controlled trial
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View abstract on PubMed
Summary
This summary is machine-generated.Flexible sigmoidoscopy screening significantly reduces colorectal cancer incidence and mortality for up to two decades. This once-only screening offers substantial long-term protection against the disease, especially in the distal colorectum.
Area Of Science
- Oncology
- Gastroenterology
- Preventive Medicine
Background
- Flexible sigmoidoscopy screening is known to reduce colorectal cancer (CRC) incidence and mortality.
- Uncertainty remains regarding the long-term duration of protection and potential sex or age differences in screening effectiveness.
Purpose Of The Study
- To assess the long-term effects of once-only flexible sigmoidoscopy screening on CRC incidence and mortality.
- To evaluate differences in screening effectiveness by sex and age after 21 years of follow-up.
Main Methods
- A multicentre randomized controlled trial (UK Flexible Sigmoidoscopy Screening Trial) involving men and women aged 55-64 years.
- Randomization (2:1) to either a control group (no further contact) or an intervention group (invited to once-only flexible sigmoidoscopy screening).
- Primary outcomes assessed were CRC incidence and mortality using intention-to-treat analyses with Kaplan-Meier estimation and hazard ratios over 21 years.
Main Results
- Colorectal cancer incidence was reduced in the screening group (3.18% vs 4.16% cumulative incidence at 21 years; HR 0.76).
- Colorectal cancer mortality was also reduced (0.97% vs 1.33% cumulative incidence at 21 years; HR 0.75).
- Screening showed greater efficacy in reducing incidence and mortality in the distal colorectum (HR 0.59 for incidence) compared to the proximal colon (HR 0.98 for incidence). The reduction in CRC incidence was more pronounced in men (HR 0.70) than women (HR 0.86).
Conclusions
- Once-only flexible sigmoidoscopy screening provides significant reductions in colorectal cancer incidence and mortality for up to two decades.
- These findings offer crucial data to inform and update national colorectal cancer screening guidelines.
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