Should the starting age for CRC screening be lowered to 45?


Dear colleagues and friends,

The start age for colorectal cancer (CRC) screening in average-risk individuals has been relatively uncontroversial and unchallenged, until recent guidelines that recommended decreasing the start age from 50 to 45 years. In this edition of Perspectives, two renowned experts, Dr. Patel and Dr. Rabeneck, debate the pros and cons of this paradigm change. This will be my final Perspectives contribution as associate editor for GI & Hep News. Thank you very much for your support and feedback, and I hope you have all enjoyed and learned from the Perspectives debates as much as I have. As always, your feedback and suggestions for future topics are welcome and can be sent to

Charles J. Kahi, MD, MS, AGAF, is professor of medicine at Indiana University, Indianapolis.

45 is the new 50


The incidence and mortality rates of CRC in individuals under the age of 50 years, or early age–onset CRC, is increasing in the United States.1 We do not fully understand the cause of this trend; however, it has been observed in multiple Westernized countries, consistent with a birth cohort effect in which generation-specific risk factors are likely responsible.1 To address this rising burden of early age–onset CRC, multiple professional societies, including the United States Preventive Services Task Force,2 now recommend decreasing the starting age for CRC screening in average-risk individuals from 50 to 45 years. These recommendations are supported by the fact that CRC incidence in 45- to 49-year-olds is now the same as that of populations already eligible for screening; the yield of screening appears to be similar among those aged 45-49 years, compared to those aged 50-59 years; and modeling studies show that the benefits outweigh the risks and costs. These factors, along with the unique benefits of early detection and prevention in young patients, support that 45 is the new 50 when it comes to CRC screening.

Swati G. Patel, MD, MS, is an associate professor of medicine in the divisions of gastroenterology & hepatology at the University of Colorado and Rocky Mountain Regional Veterans Affairs Medical Center, both in Aurora, Colo.

Dr. Swati G. Patel

CRC incidence rates among 45- to 49-year-olds now match populations that are already eligible for CRC screening. The rates among 45- to 49-year-olds now is similar to the incidence rates observed in 50-year-olds in 1992, before widespread CRC screening was performed. Overall incidence rates in 45- to 49-year-olds now match incidence rates observed in 45- to 49-year-old African Americans, a population in which the American College of Gastroenterology and the U.S. Multi-Society Task Force have recommended average-risk screening beginning at age 45.

Advanced colorectal neoplasia rates in 45- to 49-year-olds are similar to rates observed in 50- to 59-year-olds. One study found that advanced colorectal neoplasia rates (including advanced colorectal polyps and adenocarcinoma) in average risk–equivalent 45- to 49-year-olds are similar rates of 50- to 54-year-old average-risk individuals.3 Similarly, a recent systematic review and meta-analysis of 17 international studies including average-risk individuals undergoing colonoscopy found no significant difference between advanced colorectal neoplasia rates in 45- to 49-years-olds compared to 50- to 59-year-olds.4 These data suggest that expanding screening to average-risk individuals aged 45-49 years will have yield similar to that of those aged 50-59.

Modeling studies show that the benefits of screening outweigh the potential harms and costs. A recent cost-effectiveness analysis showed that starting average-risk screening at age 45 years with colonoscopy would cost $33,900 per quality-adjusted life-year (QALY) or $7,700 per QALY if annual FIT is selected as the screening modality.5 These costs are less than the widely accepted willingness to pay threshold of $50,000 per QALY and less than currently accepted average-risk screening, such as annual or biennial mammograms for breast cancer screening.

Expanding screening to 45- to 49-year-olds can improve early detection of CRC and prevention of CRC. Offering screening before age 50 years provides the opportunity to detect cancers at earlier stages, which can improve overall survival. Recent data have shown an increase in CRC incidence among 50- to 54-year-olds.1 Although the etiology of the rise in this age group is likely multifactorial (low screening rates or generational risk that individuals carry with them through the birth-cohort effect), diagnosis and removal of advanced colorectal polyps among 45- to 49-year-olds can have a positive impact on reversing this trend in 50- to 54-year-olds. Furthermore, initiating conversations about CRC screening at age 45 can improve uptake of screening among 50- to 54-year-olds who may have delayed screening when first offered at age 50.

There are unique benefits of early detection and prevention of CRC in young patients. Although the absolute incidence and mortality rates associated with CRC in those aged 45-49 are significantly lower than the rates observed in those over age 50, young individuals are more likely to be in the prime of their earning and fertility potential and are more likely to be caregivers to younger and older generations. They are more likely to face material, psychological, and behavioral financial hardships, such as difficulty paying bills. Absolute incidence rates and modeling studies that do not account for these intangible effects on survivorship also do not fully reflect the societal benefit of early detection and CRC prevention in those aged 45-49 years.

There are certainly many unanswered questions about the effects of expanding CRC screening to those age 45 and older. Ongoing studies are needed to determine the cause of rising incidence, whether screening test selection and intervals should be customized for those under age 50, and how best to ensure equitable access to screening services. Finally, expanding screening to younger individuals should not detract from the critical importance of ongoing efforts to improve screening in those over age 50. As these issues are addressed by the scientific community, we cannot stand by idly when there is sufficient evidence to support that 45 is the new 50.

Dr. Patel is associate professor of medicine in the divisions of gastroenterology & hepatology at the University of Colorado and Rocky Mountain Regional Veterans Affairs Medical Center, both in Aurora, Colo. She disclosed financial relationships with Olympus America, ERBE USA, and Freenome.


1. Siegel RL et al. J Natl Cancer Inst. 2017. doi: 10.1093/jnci/djw322.

2. USPSTF et al. JAMA. 2021 May 18;325(19):1965-77.

3. Butterly LF et al. Am J Gastroenterol. 2021 Jan;116(1):171-9.

4. Kolb JM et al. Gastroenterology. 2021 Jun. doi: 10.1053/j.gastro.2021.06.006.

5. Ladabaum U et al. Gastroenterology. 2019 Jul;157(1):137-48.


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