LB27
Population-based screening for colorectal cancer: is faecal immunochemical testing more cost-effective than guaiac-based faecal occult blood testing and flexible sigmoidoscopy?
Linda Sharp1, Lesley Tilson2, Sophie Whyte3, Alan O'Ceilleachair1, Cathal Walsh4, Cara Usher2, Paul Tappenden3, Jim Chilcott3, Anthony Staines5, Michael Barry2, Harry Comber1
1National Cancer Registry Ireland, Cork, Ireland; 2National Centre for Pharmacoeconomics, Dublin, Ireland; 3University of Sheffield, UK; 4Trinity College Dublin, Ireland; 5 Dublin City University, Ireland
Background
Several colorectal cancer screening tests are available, including
endoscopy-based tests, such as flexible sigmoidoscopy (FSIG), and faecal tests.
The faecal tests include guaiac-based occult blood tests (gFOBT), which are
used in the UK screening programmes, and immunochemical tests (FIT), which may
have better sensitivity than gFOBTs. We evaluated the cost-effectiveness of a
population-based colorectal cancer screening programme in Ireland, using gFOBT, FIT or FSIG.
Method
The screening scenarios assessed were: (1) biennial gFOBT at ages 55-74,
with reflex FIT in those with a positive gFOBT; (2) biennial FIT at ages 55-74;
and (3) once-only FSIG at age 60. A Markov model was used to follow a cohort of
55-year-old individuals over their lifetime. Model parameters were obtained
from local data, literature review and expert opinion. Costs included screening
and diagnostic tests, cancer treatment, complications, and surveillance of
screen-detected adenomas. Health outcomes were assessed in quality-adjusted
life years (QALYs). Costs and outcomes were discounted at 4% per annum.
Screening scenarios were compared with the status quo ("no
screening"). Probabilistic sensitivity analyses were undertaken.
Results
All screening scenarios were highly cost-effective compared to no
screening. In the base-case analysis, FSIG had the lowest incremental
cost-effectiveness ratio (ICER=589 per QALY gained), followed by FIT (1,696
per QALY gained), and gFOBT (4,428 per QALY gained). gFOBT was dominated.
Compared to FSIG, FIT was associated with a greater health gain, and greater
lifetime reductions in colorectal cancer incidence and mortality.
However, it was more costly than FSIG, required more colonoscopies, and would
result in more complications. The ICER for FIT versus FSIG was 2,058 per QALY
gained. Results were robust to variations in parameter estimates.
Conclusion
These results suggest that colorectal cancer screening is highly
cost-effective. A programme based on FIT could result in greater health gains
than one based on FSIG or gFOBT.
