Bowel cancer (or colorectal cancer), refers to cancer that occurs in the colon and rectum. Bowel cancer is the second most common cancer (excluding non-melanoma skin cancer) in men and the third most common cancer in women. In Ireland, bowel cancer is the third leading cause of cancer death. 

Screening involves the use of a faecal immunochemical test (FIT) to detect hidden blood in the stool, which may indicate bowel cancer. People who receive a positive FIT result are referred for colonoscopy. Depending on the results of the colonoscopy, they either return to routine screening, enter a surveillance pathway, or are referred for treatment. 

BowelScreen, Ireland’s national colorectal cancer screening programme, commenced in 2012 with the aim of screening those aged 55 to 74. As of April 2026, people aged 57 to 71 are invited for screening every two years.

This HTA was carried out in accordance with HIQA’s guidelines for the conduct of HTAs. In summary, the following took place:

• The Terms of Reference and deliverables for the HTA were agreed between HIQA and the Chair of NSAC, on behalf of NSAC.
• An Expert Advisory Group (EAG) was convened by HIQA comprising representation from relevant stakeholders. These included representation from the National Screening Service, BowelScreen, the Irish Cancer Society, Patients for Patient Safety, the National Cancer Control Programme, the National Clinical Programme for Gastroenterology and Hepatology, the National Cancer Registry Ireland, the HSE Endoscopy Programme, the HSE Laboratory Services Reform Programme, the Faculty of Radiologists and Radiation Oncologists, the Department of Health, the National Centre for Pharmacoeconomics, and HIQA. An Evaluation Team was appointed comprising HIQA staff.
• The existing BowelScreen programme pathway, and international practice regarding colorectal cancer screening, were described.
• The epidemiology and burden of disease of colorectal cancer in Ireland and internationally in those aged 50 to 54 was described.
• A review of the test accuracy of faecal immunochemical testing (FIT) for the detection of colorectal cancer in those aged 50 to 54 was conducted.
• A review of the clinical effectiveness and harms of screening in those aged 50 to 54 was conducted. 
• A review of the cost effectiveness of screening for colorectal cancer in those aged 50 to 54 was conducted.
• The budgetary implications of extending the BowelScreen programme to those aged 50 to 54 were estimated.
• The organisational implications of extending the BowelScreen programme to those aged 50 to 54 were described.
• The ethical, patient, and social considerations of extending the programme were described. 
• A draft report summarising the findings of this HTA was produced and discussed at meetings of the EAG and subsequently amended, where appropriate.
• The final draft report was circulated to the EAG for review, and was subsequently published for public consultation.
• Following review by the EAG post public consultation, the final draft of the HTA was submitted to the Board of HIQA for approval.
• Following its approval, the finalised HTA was submitted to NSAC for consideration and published on the HIQA website.

• Colorectal cancer (CRC) is the second-most common cancer in men and the third-most common cancer in women in Ireland, with approximately 2,750 new cases each year. CRC is the third leading cause of cancer death in Ireland, with approximately 1,000 CRC-related deaths annually. 
• The CRC incidence rate in those aged 50 to 54 has been relatively stable since 2013, with an average annual incidence rate of 47.3 per 100,000. While CRC mortality in age groups older than 60 in Ireland has declined over time, it has remained stable in younger age groups, including in those aged 50 to 54.
• As of November 2025, the BowelScreen programme invites people aged 58 to 70 for screening every two years. While there is a long-standing commitment to screen those aged 55 to 74, this has not yet been achieved. 
• The primary screening test used by BowelScreen is FIT, which can be completed at home. Individuals who receive a positive FIT result are referred for colonoscopy. FIT uptake rates in Ireland have remained below the minimum target of 50%, ranging from 40.6% in 2012–2015 to 46.4% in 2022–2023. 
• The primary aim of BowelScreen is to detect cancer at an earlier stage, when treatment is more likely to be successful. The detection and removal of pre-cancerous polyps through screening can also reduce CRC incidence. Considering accuracy of detection, no evidence was identified to suggest that the sensitivity and specificity of FIT for CRC, at the FIT threshold used in Ireland, differs significantly by age. 
• Screening from age 50 reduces CRC mortality compared to no screening. The risk of adverse events associated with screening is likely to be lower among younger screening participants. However, no study was identified that directly compared the clinical effectiveness of screening with a starting age of 50 to a starting age of 55.
• The evidence suggests that screening all adults from age 50 to 74 is likely to be cost effective versus screening all adults from age 55 to 74, based on a willingness-to-pay threshold of €20,000 per QALY gained.
• Compared to screening those aged 55 to 74, the incremental budget impact associated with immediate expansion to those aged 50 to 54 was estimated as €66 million over a 10-year period. These estimates are based on observed screening uptake rates in Ireland and internationally (ranging by age group from 31% to 53%). Reaching the BowelScreen-defined ‘achievable’ target uptake rate of 60% would substantially increase the resources required and would incur greater costs. The cost of expansion is further influenced by the pace of expansion and migration projections, as well as uncertainty in the underlying data.
• There are significant ongoing capacity challenges and workforce shortages in the services required by BowelScreen, including endoscopy, histopathology and diagnostic radiology. These impact on waiting lists for both BowelScreen participants and symptomatic patients. Ensuring a supply of professionals with the required level of experience and expertise to meet quality assurance standards and key performance indicators is essential to ensuring a safe and effective service.
• As the planned expansion to those aged 55 to 74 progresses, the additional demands placed on services should be carefully monitored. Extending the programme further to those aged 50 to 54, without coordinated efforts to address the existing capacity limitations, is likely to negatively impact the ability of both BowelScreen and symptomatic services to provide appropriate care. This could potentially lead to longer waiting lists and worsening diagnostic test result turnaround times. A phased approach to implementation, coupled with significant forward planning and investment in staffing and training would be required to ensure sufficient resources are in place to support the implementation of extension of screening to those aged 50 to 54. 
• An extension of the programme should incorporate efforts to enhance equity and uptake. Otherwise, extending screening to those aged 50 to 54 may serve to increase disparities if those who are at higher risk of CRC are less likely to participate.