Long-Term Colorectal Cancer Incidence and Mortality After Colonoscopy Screening According to Individuals' Risk Profiles

Optimal timing of a colonoscopy screening schedule depends on adenoma detection, adenoma risk, adherence to screening and the screening objective: A microsimulation study

Colonoscopy-based screening provides protection against colorectal cancer (CRC), but the optimal starting age and time intervals of screening colonoscopies are unknown. We aimed to determine an optimal screening schedule for the US population and its dependencies on the objective of screening (life years gained or incidence, mortality, or cost reduction) and the setting in which screening is performed. We used our established open-source microsimulation model CMOST to calculate optimized colonoscopy schedules with one, two, three or four screening colonoscopies between 20 and 90 years of age. A single screening colonoscopy was most effective in reducing life years lost from CRC when performed at 55 years of age. Two, three and four screening colonoscopy schedules saved a maximum number of life years when performed between 49-64 years; 44-69 years; and 40-72 years; respectively. However, for maximum incidence and mortality reduction, screening colonoscopies needed to be scheduled 4-8 years later in life. The optimum was also influenced by adenoma detection efficiency with lower values for these parameters favoring a later starting age of screening. Low adherence to screening consistently favored a later start and an earlier end of screening. In a personalized approach, optimal screening would start earlier for high-risk patients and later for low-risk individuals. In conclusion, our microsimulation-based approach supports colonoscopy screening schedule between 45 and 75 years of age but the precise timing depends on the objective of screening, as well as assumptions regarding individual CRC risk, efficiency of adenoma detection during colonoscopy and adherence to screening.

External validation of the colorectal cancer risk score LiFeCRC using food frequency questions in the HUNT study

PURPOSE

To mitigate the increasing colorectal cancer (CRC) incidence globally and prevent CRC at the individual level, individual lifestyle information needs to be easily translated into CRC risk assessment. Several CRC risk prediction models exist and their clinical usefulness depends on their ease of use. Our objectives were to assess and externally validate the LiFeCRC score in our independent, unselected population and to investigate the use of simpler food frequency measurements in the score.

METHODS

Incidental colon and rectal cancer cases were compared to the general population among 78,580 individuals participating in a longitudinal health study in Norway (HUNT). Vegetable, dairy product, processed meat and sugar/confectionary consumption was scored based on food frequency. The LiFeCRC risk score was calculated for each individual.

RESULTS

Over a median of 10 years following participation in HUNT, colon cancer was diagnosed in 1355 patients and rectal cancer was diagnosed in 473 patients. The LiFeCRC score using food frequencies demonstrated good discrimination in CRC overall (AUC 0.77) and in sex-specific models (AUC men 0.76 and women 0.77) in this population also including individuals ≥ 70 years and patients with diabetes. It performed somewhat better in colon (AUC 0.80) than in rectal cancer (AUC 0.72) and worked best for female colon cancer (AUC 0.81).

CONCLUSION

Readily available clinical variables and food frequency questions in a modified LiFeCRC score can identify patients at risk of CRC and may improve primary prevention by motivating to lifestyle change or participation in the CRC screening programme.

Implementation of an organized colorectal cancer screening program through quantitative fecal immunochemical test followed by colonoscopy in an urban low-income community: Guidance and strategies

Fecal Immunochemical Test (FIT) followed by a colonoscopy is an efficacious strategy to improve the adenoma detection rate and Colorectal Cancer (CRC). There is no organized national screening program for CRC in Brazil. The aim of this research was to describe the implementation of an organized screening program for CRC through FIT followed by colonoscopy, in an urban low-income community of São Paulo city. The endpoints of the study were: FIT participation rate, FIT positivity rate, colonoscopy compliance rate, Positive Predictive Values (PPV) for adenoma and CRC, and the rate of complications. From May 2016 to October 2019, asymptomatic individuals, 50-75 years old, received a free kit to perform the FIT. Positive FIT (≥ 50 ng/mL) individuals were referred to colonoscopy. 10,057 individuals returned the stool sample for analysis, of which (98.2%) 9,881 were valid. Women represented 64.8% of the participants. 55.3% of individuals did not complete elementary school. Positive FIT was 7.8% (776/9881). The colonoscopy compliance rate was 68.9% (535/776). There were no major colonoscopy complications. Adenoma were detected in 63.2% (332/525) of individuals. Advanced adenomatous lesions were found in 31.4% (165/525). CRC was diagnosed in 5.9% (31/525), characterized as adenocarcinoma: in situ in 3.2% (1/31), intramucosal in 29% (9/31), and invasive in 67.7% (21/31). Endoscopic treatment with curative intent for CRC was performed in 45.2% (14/31) of the cases. Therefore, in an urban low-income community, an organized CRC screening using FIT followed by colonoscopy ensued a high participation rate, and high predictive positive value for both, adenoma and CRC.

Colorectal Cancer Risk Assessment and Precision Approaches to Screening: Brave New World or Worlds Apart?

Current colorectal cancer (CRC) screening recommendations take a "one-size-fits-all" approach using age as the major criterion to initiate screening. Precision screening that incorporates factors beyond age to risk stratify individuals could improve on current approaches and optimally use available resources with benefits for patients, providers, and health care systems. Prediction models could identify high-risk groups who would benefit from more intensive screening, while low-risk groups could be recommended less intensive screening incorporating noninvasive screening modalities. In addition to age, prediction models incorporate well-established risk factors such as genetics (eg, family CRC history, germline, and polygenic risk scores), lifestyle (eg, smoking, alcohol, diet, and physical inactivity), sex, and race and ethnicity among others. Although several risk prediction models have been validated, few have been systematically studied for risk-adapted population CRC screening. In order to envisage clinical implementation of precision screening in the future, it will be critical to develop reliable and accurate prediction models that apply to all individuals in a population; prospectively study risk-adapted CRC screening on the population level; garner acceptance from patients and providers; and assess feasibility, resources, cost, and cost-effectiveness of these new paradigms. This review evaluates the current state of risk prediction modeling and provides a roadmap for future implementation of precision CRC screening.

Risk-Adapted Starting Age for Personalized Colorectal Cancer Screening: Validated Evidence From National Population-Based Studies

BACKGROUND & AIMS

A one-size-fits-all approach to colorectal cancer (CRC) screening that does not account for CRC risk factors is not conducive to personalized screening. On the basis of the principle of equal management of equal risks, we aimed to tailor and validate risk-adapted starting ages of CRC screening for individuals with different CRC risk factors.

METHODS

A multi-center community-based population cohort (N = 3,165,088) was used to evaluate the starting age of CRC screening with comprehensive consideration of risk factors. Age-specific 10-year cumulative risk curves were used to determine when individuals at greater risk for CRC reached the same risk level as the 50-year-old general population, which is currently the recommended starting age for CRC screening in China.

RESULTS

During the study follow-up period (2013-2021), 4,840 incident CRCs were recorded. Family history of CRC, adverse lifestyle, and comorbidities demonstrated heterogeneous associations with CRC risk (hazard ratios, 1.05-1.55; P < .05). Men and women with CRC family history and at least 2 risk factors reached the standard benchmark risk (0.28%) for screening at the age of 40, 10 years earlier than their peers without risk factors in the general population. Proposed starting ages for CRC screening were validated in an independent community-based population cohort (N = 1,023,367).

CONCLUSIONS

We determined a risk-adapted CRC screening starting age for individuals with various CRC risk factors. Earlier, personalized screening based on these findings could allow for scarce health resources to be dedicated to individuals who benefit most.

Polygenic Risk Score for Defining Personalized Surveillance Intervals After Adenoma Detection and Removal at Colonoscopy

BACKGROUND & AIMS

Polygenic risk scores (PRSs) could help to define personalized colorectal cancer (CRC) screening strategies. The aim of this study was to evaluate whether a PRS, along with adenoma characteristics, could help to define more personalized and risk-adapted surveillance intervals.

METHODS

In a population-based, case-control study from Germany, detailed information on previous colonoscopies and a PRS based on 140 CRC-related, single-nucleotide polymorphisms was obtained from 4696 CRC cases and 3709 controls. Participants were classified as having low, medium, or high genetic risk according to tertiles of PRSs among controls. We calculated the absolute risk of CRC based on the PRS and colonoscopy history and findings.

RESULTS

We observed major variations of CRC risk according to the PRS, including among individuals with detection and removal of adenomas at colonoscopy. For instance, the estimated 10-year absolute risk of CRC for 50-year-old men and women with no polyps, for whom repeat screening colonoscopy is recommended after 10 years only, was 0.2%. Equivalent absolute risks were estimated for people with low-risk adenomas and low PRS. However, the same levels of absolute risk were reached within 3 to 5 years by those with low-risk adenomas and high PRS and with high-risk adenomas irrespective of the PRS.

CONCLUSIONS

Consideration of genetic predisposition to CRC risk, as determined by a PRS, could help to define personalized, risk-adapted surveillance intervals after detection and removal of adenomas at screening colonoscopy. However, whether the risk variation is strong enough to direct clinical risk stratification needs to be explored further.

Endoscopic Screening and Risk of Colorectal Cancer according to Type 2 Diabetes Status

Current recommendations for colorectal cancer screening have not accounted for type 2 diabetes (T2D) status. It remains unknown whether the colorectal cancer-preventive benefit of endoscopic screening and the recommended age for screening initiation differ by T2D. Among 166,307 women (Nurses' Health Study I and II, 1988-2017) and 42,875 men (Health Professionals Follow-up Study, 1988-2016), endoscopic screening and T2D diagnosis were biennially updated. We calculated endoscopic screening-associated hazard ratios (HR) and absolute risk reductions (ARR) for colorectal cancer incidence and mortality according to T2D, and age-specific colorectal cancer incidence according to T2D. During a median of 26 years of follow-up, we documented 3,457 colorectal cancer cases and 1,129 colorectal cancer deaths. Endoscopic screening was associated with a similar HR of colorectal cancer incidence in the T2D and non-T2D groups (P-multiplicative interaction = 0.57). In contrast, the endoscopic screening-associated ARR for colorectal cancer incidence was higher in the T2D group (2.36%; 95% CI, 1.55%-3.13%) than in the non-T2D group (1.73%; 95% CI, 1.29%-2.16%; P-additive interaction = 0.01). Individuals without T2D attained a 10-year cumulative risk of 0.35% at the benchmark age of 45 years, whereas those with T2D reached this threshold risk level at the age of 36 years. Similar results were observed for colorectal cancer mortality. In conclusion, the absolute benefit of endoscopic screening for colorectal cancer prevention may be substantially higher for individuals with T2D compared with those without T2D. Although T2D is comparatively rare prior to the fifth decade of life, the rising incidence of young-onset T2D and heightened colorectal cancer risk associated with T2D support the consideration of earlier endoscopic screening in individuals with T2D.

PREVENTION RELEVANCE

The endoscopic screening-associated ARRs for colorectal cancer incidence and mortality were higher for individuals with T2D than those without T2D. Endoscopic screening confers a greater benefit for colorectal cancer prevention among T2D individuals, who may also benefit from an earlier screening than the current recommendation.

FIT-based risk-stratification model effectively screens colorectal neoplasia and early-onset colorectal cancer in Chinese population: a nationwide multicenter prospective study

No fully validated risk-stratification strategies have been established in China where colonoscopies resources are limited. We aimed to develop and validate a fecal immunochemical test (FIT)-based risk-stratification model for colorectal neoplasia (CN); 10,164 individuals were recruited from 175 centers nationwide and were randomly allocated to the derivation (n = 6776) or validation cohort (n = 3388). Multivariate logistic analyses were performed to develop the National Colorectal Polyp Care (NCPC) score, which formed the risk-stratification model along with FIT. The NCPC score was developed from eight independent predicting factors and divided into three levels: low risk (LR 0–14), intermediate risk (IR 15–17), and high risk (HR 18–28). Individuals with IR or HR of NCPC score or FIT+ were classified as increased-risk individuals in the risk-stratification model and were recommended for colonoscopy. The IR/HR of NCPC score showed a higher prevalence of CNs (21.8%/32.8% vs. 11.0%, P < 0.001) and ACNs (4.3%/9.2% vs. 2.0%, P < 0.001) than LR, which was also confirmed in the validation cohort. Similar relative risks and predictive performances were demonstrated between non-specific gastrointestinal symptoms (NSGS) and asymptomatic cohort. The risk-stratification model identified 73.5% CN, 82.6% ACN, and 93.6% CRC when guiding 52.7% individuals to receive colonoscopy and identified 55.8% early-onset ACNs and 72.7% early-onset CRCs with only 25.6% young individuals receiving colonoscopy. The risk-stratification model showed a good risk-stratification ability for CN and early-onset CRCs in Chinese population, including individuals with NSGS and young age.

Third Asia-Pacific consensus recommendations on colorectal cancer screening and postpolypectomy surveillance

The Asia-Pacific region has the largest number of cases of colorectal cancer (CRC) and one of the highest levels of mortality due to this condition in the world. Since the publishing of two consensus recommendations in 2008 and 2015, significant advancements have been made in our knowledge of epidemiology, pathology and the natural history of the adenoma-carcinoma progression. Based on the most updated epidemiological and clinical studies in this region, considering literature from international studies, and adopting the modified Delphi process, the Asia-Pacific Working Group on Colorectal Cancer Screening has updated and revised their recommendations on (1) screening methods and preferred strategies; (2) age for starting and terminating screening for CRC; (3) screening for individuals with a family history of CRC or advanced adenoma; (4) surveillance for those with adenomas; (5) screening and surveillance for sessile serrated lesions and (6) quality assurance of screening programmes. Thirteen countries/regions in the Asia-Pacific region were represented in this exercise. International advisors from North America and Europe were invited to participate.

Adenoma Detection Rate and Clinical Characteristics Influence Advanced Neoplasia Risk After Colorectal Polypectomy

BACKGROUND AND AIMS

Postpolypectomy risk stratification for subsequent metachronous advanced neoplasia (MAN) is imprecise and does not account for colonoscopist adenoma detection rate (ADR). Our aim was to assess association of ADR with MAN and create a prediction model for postpolypectomy risk stratification incorporating ADR and other factors.

METHODS

We conducted a retrospective cohort study of individuals with baseline polypectomy and subsequent surveillance colonoscopy from 2004 to 2016 within the U.S. Department of Veterans Affairs (VA). Clinical factors, polyp findings, and baseline colonoscopist ADR were considered for the model. Model performance (sensitivity, specificity, and area under the curve) for identifying individuals with MAN was compared with 2020 U.S. Multi-Society Task Force on Colorectal Cancer (USMSTF) surveillance recommendations.

RESULTS

A total of 30,897 individuals were randomly assigned 2:1 into independent model training and validation sets. Increasing age, male sex, diabetes, current smoking, adenoma number, polyp location, adenoma ≥10 mm or with tubulovillous/villous features, and decreasing colonoscopist ADR were independently associated with MAN. A range of 1.48- to 1.66-fold increased risk for MAN was observed for ADR in the lowest 3 quintiles (ADR <19.7%-39.3%) vs the highest quintile (ADR >47.0%). When the final model selected based on the training set was applied to the validation set, improved sensitivity and specificity over 2020 USMSTF risk stratification were achieved (P = .001), with an area under the curve of 0.62 (95% confidence interval, 0.60-0.64).

CONCLUSIONS

Colonoscopist ADR is associated with MAN. Combining clinical factors and ADR for risk stratification has potential to improve postpolypectomy risk stratification. Improving ADR is likely to improve postpolypectomy outcomes.

Tobacco Smoking and Gastrointestinal Cancer Risk

BACKGROUND

Smoking tobacco is the most preventable cause of gastrointestinal (GI) cancer disease in Germany. The more and the longer you smoke, the higher your risk of GI cancer. About 28% of 18-64 year-old Germans are current smokers; in addition, 11% of the population is regularly exposed to secondhand tobacco smoke.

SUMMARY

Tobacco use is causally associated with esophageal, gastric, pancreatic, biliary, hepatocellular, colorectal, and anal cancers. Combining smoking with alcohol use, excess body weight, diabetes, or chronic infections synergistically enhances GI cancer risk. Smoking cessation effectively reduces tobacco-associated GI cancer risk.

KEY MESSAGES

Smokers should be encouraged to stop smoking tobacco and join programs of risk-adaptive cancer screening.

Changes in Lifestyle Factors After Endoscopic Screening: A Prospective Study in the United States

BACKGROUND

Endoscopic screening and adherence to a healthy lifestyle are major avenues for colorectal cancer (CRC) prevention. We investigated changes in lifestyles after endoscopic screening.

METHODS

We drew data from 76,303 pairs of time- and age-matched individuals who had and had not, respectively, reported first time endoscopic screening, in the 3 cohorts (Nurses' Health Study I and II and the Health Professionals Follow-up Study). Detailed information was collected every 2-4 years on endoscopy screening, 12 lifestyle factors (including smoking, physical activity, regular use of aspirin/nonsteroidal anti-inflammatory drugs, body weight, and 8 dietary factors), and adherence to a healthy lifestyle based on a score defined by 5 major lifestyle factors (smoking, alcohol, body weight, physical activity, and diet). We assessed changes in lifestyle from pre- to post-screening periods for the matched pairs. We also conducted subgroup analysis according to screening findings (negative, low- and high-risk polyps, and CRC).

RESULTS

Endoscopic screening was associated with higher prevalence of adherence to a healthy lifestyle (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.04-1.16). The association strengthened with the severity of the screening findings, with an OR of 1.09 (95% CI, 1.03-1.15) for negative screening, 1.19 (95% CI, 1.07-1.33) for low-risk polyps, 1.42 (95% CI, 1.14-1.77) for high-risk polyps, and 1.55 (95% CI, 1.17-2.05) for CRC. The individual lifestyle factors and diet showed modest change.

CONCLUSIONS

Endoscopic screening was associated with a modest improvement in healthy lifestyles, particularly in individuals with more severe endoscopic findings. Further efforts of integrating lifestyle medicine into the screening setting are needed, to better leverage the teachable moment in improving CRC prevention.

Optimizing Positivity Thresholds for a Risk-Adapted Screening Strategy in Colorectal Cancer Screening

INTRODUCTION

Risk-adapted screening combining the Asia-Pacific Colorectal Screening score, fecal immunochemical test (FIT), and colonoscopy improved the yield of colorectal cancer screening than FIT. However, the optimal positivity thresholds of risk scoring and FIT of such a strategy warrant further investigation.

METHODS

We included 3,407 participants aged 50-74 years undergoing colonoscopy from a colorectal cancer screening trial. For the risk-adapted screening strategy, subjects were referred for subsequent colonoscopy or FIT according to their risk scores. Diagnostic performance was evaluated for FIT and the risk-adapted screening method with various positivity thresholds. Furthermore, a modeled screening cohort was established to compare the yield and cost using colonoscopy, FIT, and the risk-adapted screening method in a single round of screening.

RESULTS

Risk-adapted screening method had higher sensitivity for advanced neoplasm (AN) (27.6%-76.3% vs 13.8%-17.3%) but lower specificity (46.6%-90.8% vs 97.4%-98.8%) than FIT did. In a modeled screening cohort, FIT-based screening would be slightly affected because the threshold varied with a reduction of 76.0%-80.9% in AN detection and 82.0%-84.4% in cost when compared with colonoscopy. By contrast, adjusting the threshold of Asia-Pacific Colorectal Screening score from 3 to 5 points for risk-adapted screening varied from an increase of 12.6%-14.1% to a decrease of 55.6%-60.1% in AN detection, with the reduction of cost from 4.2%-5.3% rising to 66.4%-68.5%.

DISCUSSION

With an appropriate positivity threshold tailored to clinical practice, the risk-adapted screening could save colonoscopy resources and cost compared with the colonoscopy-only and FIT-only strategies.