Past Highlights: Colorectal

2008 Recommendations

The U.S. Preventive Services Task Force (USPSTF) requested a decision analysis to inform their 2008 update of the recommendations for colorectal cancer screening. The objective was to assess life-years gained and colonoscopy requirements for colorectal cancer screening strategies and identify a set of recommendable screening strategies. The decision analysis used two of CISNET's microsimulation models, MISCAN and SimCRC, to assess life-years gained and colonoscopy requirements for colorectal cancer screening strategies, and identify a set of recommendable screening strategies.

Results of the study were published in the following article in the Annals of Internal Medicine: Zauber AG, Lansdorp-Vogelaar I, Knudsen AB, Wilschut J, van Ballegooijen M, Kuntz KM. Evaluating Test Strategies for Colorectal Cancer Screening: A Decision Analysis for the U.S. Preventive Services Task Force. Ann Intern Med 2008 Oct 6. [Full-text PDF Version].

The 2008 USPSTF recommendations for colorectal cancer screening are now outdated and were replaced by the 2016 recommendations.

2016 Recommendations

The 2016 USPSTF recommendations for colorectal cancer screening were issued in June 2016. The CISNET-Colorectal Working Group authored the modeling study for the 2016 recommendations. The PDF Version of the modeling study is available.

The final recommendation statement was published on June 21, 2016. US Preventive Services Task Force. June 21, 2016 Recommendation Statement. Screening for Colorectal Cancer. Recommendation Statement. JAMA. 2016;315(23):2564-2575. [Full-text article]

The final evidence summary is available (PDF Version).

Comparative modeling with SimCRC, CRC-SPIN, and MISCAN-Colon was used for the USPSTF screening recommendation update. A hypothetical cohort of 10 million previously unscreened 40 year olds with no prior diagnosis was simulated. Assuming 100% screening compliance, the cohort was screened with sensitive guaiac-based fecal occult blood testing, fecal immunochemical testing, multi-target stool DNA, flexible sigmoidoscopy with or without stool testing, computed tomographic colonography, or colonoscopy. The models considered age to start screening beginning at 45, 50, and 55 years and age to end screening at 75, 80, and 85 years, with varying intervals per screening modality. Overall, colonoscopy every 10 years, annual fecal immunochemical test, flexible sigmoidoscopy every 10 years with annual FIT, and computed tomographic colonography every 5 years performed from ages 50‒75 years provided similar life-years gained and a comparable balance of benefit and screening burden. Methods and recommendations are described in more detail in the 2016 JAMA article cited above.

The 2016 USPSTF recommendations for colorectal cancer screening are now outdated and have been replaced by the 2021 recommendations.

2021 Recommendations

The 2021 USPSTF recommendations for colorectal cancer screening were issued in May 2021. The CISNET-Colorectal Working Group authored the modeling study for the 2021 recommendations. The PDF Version  of the modeling study is available.

The final recommendation statement was published on May 18, 2021. Screening for Colorectal Cancer: U.S. Preventive Services Task Force Recommendation Statement. JAMA. 2021;325(19):1965-1977. [Full-text article]

The final evidence summary is available (PDF Version).

The USPSTF commissioned the CISNET-Colon models (SIMCRC, CRC-SPIN, and MISCAN), along with a systematic review on the effectiveness, harms, and test accuracy of colorectal cancer screening tests, to update the 2016 colorectal cancer screening recommendations for 2021. The models simulated a hypothetical cohort of average-risk adults who were previously unscreened and free of colorectal cancer. Assuming 100% adherence, the analysis provided estimates of the benefits, burdens, and harms of different screening modalities and intervals, as well as optimal ages to begin and end screening. The modelers concluded that starting colorectal cancer at age 45 provides additional life-years gained with only limited additional burden and harms, compared with starting at age 50. Assuming full adherence, findings were similar by subgroups defined by sex and race. These findings, coupled with data showing the increasing rates of colorectal cancer incidence in people younger than 50, informed the Task Force’s recommendation for all adults at average risk to begin colorectal cancer screening at age 45. Methods and findings are described in further detail in the JAMA article cited above.

With advances in treating Cystic Fibrosis (CF), CF patients are living into middle age. However, with this increased survivorship, the risk of colorectal cancer (CRC) has also increased compared to the general average-risk population. We partnered with the Cystic Fibrosis Foundation to assess the cost-effectiveness of screening in the CF population, and to develop screening recommendations from these results. The MISCAN-Colon model was adjusted to the increased risk of CRC in CF patients (with and without organ transplant). Colonoscopy every 5 years starting at age 40 was the optimal strategy for CF patient without an organ transplant, and colonoscopy starting at age 30‒35 was suggested for CF patients with an organ transplant. Methods and recommendations are described in more detail in this publication.

A simulation study (Rutter et al., 2018) was used to estimate the change in lifetime screening benefits when time to follow-up for breast, cervical, and colorectal cancers was increased. Estimates were based on four independently developed microsimulation models that each simulated the life course of adults eligible for screening of breast cancer (women aged 50‒74 years, biennial mammography), cervical cancer (women aged 21‒65 years, triennial Papanicolaou testing), or colorectal cancer (adults aged 50‒75 years, fecal immunochemical test). For each cancer type, diagnostic testing was at 3, 6, and 12 months after an abnormal screening exam. The authors found that longer times to diagnostic testing after an abnormal screening test can decrease the effectiveness of screening, but the impact varied substantially by cancer type. Understanding the impact of time to diagnostic testing on screening effectiveness can help inform quality improvement efforts. Methods and findings are described in more detail in Rutter et al., 2018.