Early-Age Onset Colorectal Neoplasia in Average-Risk Individuals Undergoing Screening Colonoscopy: A Systematic Review and Meta-Analysis

A Score to Predict Advanced Colorectal Neoplasia in Adults Younger than Age 45

BACKGROUND

Early-onset colorectal cancer (CRC) requires identifying adults at heightened risk of advanced colorectal neoplasia (AN) who may warrant colonoscopy initiation < age 45 years.

AIMS

We aim to develop and validate a model estimating the likelihood of AN in adults age < 45 years.

METHODS

We performed a cross-sectional analysis of adults' ages 18-44 years who underwent a colonoscopy between 2011 and 2021 at a tertiary center. Subjects with AN constituted the case group while those with a normal colonoscopy or non-advanced neoplasia (NAN) formed the control group. We used backward elimination multivariable logistic regression methods to construct a model based on significant associations (p < 0.05) between risk factors and the presence of AN in a randomly selected training set and confirmed the associations in a validation set.

RESULTS

AN was detected in 346 (3.7%) of the 9,446 participants included. The reduced logistic regression model based on the training set identified BMI (p = 0.0157), family history of CRC (first-degree relative < 60, p < 0.0001; other family history of CRC p = 0.0117), and tobacco use (current vs. never, p = 0.0015, former vs. never, p = 0.0009) as risk factors for AN. In the validation set, the model exhibited moderate discriminatory power (c-statistic 0.645). The prediction score estimated the likelihood of detecting AN in the complete dataset, from 1.8% for individuals scoring 1 to > 14% for individuals scoring ≥ 9.

CONCLUSION

We developed and internally validated a simple score using clinical factors which successfully predicts the likelihood of AN in adults < 45 years undergoing colonoscopy. Once externally validated, the proposed risk score may be useful for individualized CRC screening strategies.

Risk of Advanced Adenomas in Siblings Aged ≤ 50 Years of Patients with Early-Onset Colorectal Advanced Adenomas

PURPOSE

The risk of colorectal advanced adenomas (CAAs) and colorectal cancer (CRC) in siblings aged ≤ 50 of patients diagnosed with early-onset CAAs (E-CAAs), defined as having CAA at or below 50 years, is poorly understood. This study examined the risks of adenomas, CAA, and CRC in siblings aged ≤ 50 of patients diagnosed with E-CAA.

METHODS

This case-control study was conducted at a tertiary hospital in Vietnam. The participants included 96 cases who were siblings aged ≤ 50 of patients diagnosed with E-CAA. Controls were randomly selected from consecutive patients aged ≤ 50 who did not have siblings diagnosed with E-CAA. Controls were matched to cases in a 2:1 ratio for age, sex, and smoking status.

RESULTS

The mean age was similar between cases (40.9 ± 6.0 years) and controls (41.1 ± 6.0 years). Except for indications for colonoscopy, there were no significant differences in the baseline demographics between the two groups. A heightened risk of CAA was documented in cases compared with controls (odds ratio [OR] 6.33; 95% confidence interval [CI] 1.43-43.8; P = 0.018). This increased risk was more pronounced in males (OR 13.7; 95% CI 1.23-262; P = 0.006). Cases had higher risks of colorectal adenomas (OR 2.43; 95% CI 1.27-4.67; P = 0.009) and colorectal neoplasia (OR 2.33; 95% CI 1.24-4.40; P = 0.011) than those in controls.

CONCLUSION

Siblings aged ≤ 50 of patients diagnosed with E-CAA have an increased risk of adenomas, CAA, and colorectal neoplasia. CRC screening should be initiated early in these high-risk individuals.

Early Detection and Age-Comparative Analysis of Colorectal Cancer Screening: Insights from the Turkish Population

BACKGROUND

This study aimed to evaluate the diagnostic yield of colonoscopy in asymptomatic individuals aged 45-49 years compared with those aged 50-54 years in a Turkish population, providing insights into region-specific screening strategies.

METHODS

This retrospective multicenter study was conducted across three tertiary endoscopy units in Turkey. Screening colonoscopy data from 3943 asymptomatic individuals aged 45-54 years between 2018 and 2023 were analyzed. The patients were stratified into two groups: 45-49 years (Group 1) and 50-54 years (Group 2). Demographic characteristics, polyp size, histological features, and prevalence of early-onset advanced colorectal neoplasia (EAO-aCRN) were assessed.

RESULTS

A total of 3943 patients were included, with 862 in Group 1 (45-49 years) and 3081 in Group 2 (50-54 years). The polyp detection rate was 16.6% in Group 1 and 22.9% in Group 2 (p < 0.001). The adenoma detection rates were 10.8% and 13.9% in Groups 1 and 2, respectively (p = 0.018). The advanced polyp detection rates were 3.2% and 7.3% in Groups 1 and 2, respectively (p < 0.001). Mean polyp size was 6.5 ± 5.1 mm in Group 1 and 8.8 ± 8.4 mm in Group 2 (p < 0.001). The mean number of polyps per patient was 1.5 ± 0.8 in Group 1 and 1.9 ± 1.6 in Group 2 (p = 0.023). Advanced neoplasia was detected in 16.6% of Group 1 patients compared with 22.9% of Group 2 patients (p < 0.001).

CONCLUSIONS

While CRC screening at age 45 demonstrated lower detection rates of polyps and advanced neoplasia than at age 50, the higher prevalence of EAO-CRN among 45-49-year-olds in Turkey underscores the importance of early screening in high-risk populations. Tailored regional strategies incorporating individual risk factors are crucial for optimizing CRC prevention policies.

Random forests algorithm using basic medical data for predicting the presence of colonic polyps

Background

Colorectal cancer is considered to be triggered by the malignant transformation of colorectal polyps. Early diagnosis and excision of colorectal polyps has been found to lower the mortality and morbidity associated with colorectal cancer.

Objective

The aim of this study is to offer a predictive model for the presence of colorectal polyps based on Random Forests machine learning algorithm, using basic patient information and common laboratory test results.

Materials and methods

164 patients were included in the study. The following data was collected: sex, residence, age, diabetes mellitus, body mass index, fasting blood glucose levels, hemoglobin, platelets, total, LDL and HLD cholesterol, triglycerides, serum glutamic-oxaloacetic transaminase, chronic gastritis, presence of colonic polyps at colonoscopy. 80% of patients were included in the training set for creating a Random forests algorithm, 20% were in the test set. External validation was performed on data from 42 patients. The performance of the Random Forests was compared with the performance of a generalized linear model (GLM) and support vector machine (SVM) built and tested on the same datasets.

Results

The Random Forest prediction model gave an AUC of 0.820 on the test set. The top five variables in order of importance were: body mass index, platelets, hemoglobin, triglycerides, glutamic-oxaloacetic transaminase. For external validation, the AUC was 0.79. GLM performance in internal validation was an AUC of 0.788, while for external validation AUC-0.65. For SVN, the AUC - 0.785 for internal validation and 0.685 for the external validation dataset.

Conclusions

A random forest prediction model was developed using patient's demographic data, medical history and common blood tests results. This algorithm can foresee, with good predictive power, the presence of colonic polyps.

Impact of Time Period and Birth Cohort on the Trend of Advanced Neoplasm Prevalence in the 40-49 Average-Risk Screening Population

BACKGROUND AND AIMS

Early-onset colorectal cancer (CRC) is increasing globally. While the United States has lowered the age of initiation of screening to 45 years, other countries still start screening at 50 years of age. In Taiwan, the incidence of CRC has declined in 55- to 74-year-olds after the initiation of screening, but still increased in those 50-54 years of age, potentially due to the rising precancerous lesion incidence in 40- to 49-year-olds. This study aimed to explore the chronological trend of the prevalence of colorectal advanced neoplasms (AN) in the screening population 40-54 years of age.

METHODS

We retrospectively analyzed a screening colonoscopy cohort for prevalence of AN in average-risk subjects 40-54 years of age from 2003 to 2019. Logistic regression was used to distinguish cohort effect from time-period effect on the prevalence of AN.

RESULTS

In total, 27,805 subjects (52.1% male) were enrolled. There were notable increases in prevalence of AN in all 3 age groups during the 17-year span, but these were more rapid in those 40-44 years of age (0.99% to 3.22%) and 45-49 years of age (2.50% to 4.19%). Those 50-54 years of age had a higher risk of AN (adjusted odds ratio [aOR], 1.62; 95% confidence interval [CI], 1.19-2.19) in 2003-2008 but not in later periods (2009-2014: aOR, 1.08; 95% CI, 0.83-1.41; 2015-2019: aOR, 0.76; 95% CI, 0.56-1.03) when compared with those 45-49 years of age.

CONCLUSION

The prevalence of AN in those 40-54 years of age increased in the Taiwanese population, with a later birth cohort having a higher prevalence of AN. However, the prevalence of AN in those 45-49 years of age increased more remarkably and approximated that in those 50-54 years of age, which may justify earlier initiation of CRC screening in those 45 years of age.

PET-Assessed Metabolic Tumor Volume Across the Spectrum of Solid-Organ Malignancies: A Review of the Literature

Solid-organ malignancies represent a significant disease burden and remain one of the leading causes of death globally. In the past few decades, the rapid evolution of imaging modalities has shifted the paradigm towards image-based precision medicine, especially in the care of patients with solid-organ malignancies. Metabolic tumor volume (MTV) is one such semi-quantitative parameter obtained from positron emission tomography (PET) imaging with 18F-fluorodeoxyglucose (FDG) that has been shown to have significant implications in the clinical oncology setting. Across various solid tumor malignancies, including lung cancer, head and neck cancer, breast cancer, esophageal cancer, and colorectal cancer, the current literature has demonstrated an association between MTV and various clinical outcomes. MTV may be used in conjunction with several existing and established clinical parameters to help inform risk stratification and treatment strategies and predict outcomes in cancer. Optimizing such volumetric parameters is paramount for advancing efforts to advance cancer care for our patients. While such advancements are made, it is important to investigate and address the limitations of MTV, including variability in terms of measurement methods, a lack of standardized cut-off values, and the impact of inherent tumor heterogeneity. Despite these limitations, which can precipitate challenges in standardization, MTV as a prognostic factor has great potential and opens an avenue for the future integration of technology into an image-based precision medicine model of care for cancer patients. This article serves as a narrative review and explores the utility and limitations of PET-MTV in various settings of solid-organ malignancy.

Evaluation of the Relationship Between Colorectal Cancer Incidence and Colonoscopy: The Importance of Early Diagnosis

Objective The present study evaluated the relationship between the incidence of colorectal cancer and colonoscopy in Santa Catarina from 2018 to 2022.

Methods Observational study of ecological type, which includes all confirmed cases of CRC in the state of Santa Catarina from 2018 to 2022, across health macro-regions. The data were obtained from SINAN, through TABNET/DATASUS. The variables gender, age group, race, type of care, average cost per hospitalization, days of stay, deaths, and mortality rates were evaluated.

Results In the period from 2018 to 2022, there were more than 28,000 cases of CRC in the state of Santa Catarina, with the Grande Oeste region being responsible for the highest incidence throughout the studied period. The main age group is between 70 and 79 years old; As for gender, most cases are predominantly male; about race, white ethnicity is predominant; the nature of service is, for the most part, elective; the average value per hospital stay is 2,355.41; total hospital stay days are 120,924; the number of deaths is 1553 and the mortality rate is (5.44/100.00). Regarding colonoscopy, the largest number of colonoscopies performed was in Grande Florianópolis.

Conclusion There is a high incidence of CRC cases in the state of Santa Catarina. Males and those aged 70 to 79 are the most affected by CRC in Santa Catarina. The Grande Oeste region has a higher incidence of cases compared with other health macro-regions.

The Efficacy of Real-time Computer-aided Detection of Colonic Neoplasia in Community Practice: A Pragmatic Randomized Controlled Trial

BACKGROUND & AIMS

The use of computer-aided detection (CADe) has increased the adenoma detection rates (ADRs) during colorectal cancer (CRC) screening/surveillance in randomized controlled trials (RCTs) but has not shown benefit in real-world implementation studies. We performed a single-center pragmatic RCT to evaluate the impact of real-time CADe on ADRs in colonoscopy performed by community gastroenterologists.

METHODS

We enrolled 1100 patients undergoing colonoscopy for CRC screening, surveillance, positive fecal-immunohistochemical tests, and diagnostic indications at one community-based center from September 2022 to March 2023. Patients were randomly assigned (1:1) to traditional colonoscopy or real-time CADe. Blinded pathologists analyzed histopathologic findings. The primary outcome was ADR (the percentage of patients with at least 1 histologically proven adenoma or carcinoma). Secondary outcomes were adenomas detected per colonoscopy (APC), sessile-serrated lesion detection rate, and non-neoplastic resection rate.

RESULTS

The median age was 55.5 years (interquartile range, 50-62 years), 61% were female, 72.7% were of Hispanic ethnicity, and 9.1% had inadequate bowel preparation. The ADR for the CADe group was significantly higher than the traditional colonoscopy group (42.5% vs 34.4%; P = .005). The mean APC was significantly higher in the CADe group compared with the traditional colonoscopy group (0.89 ± 1.46 vs 0.60 ± 1.12; P < .001). The improvement in adenoma detection was driven by increased detection of <5 mm adenomas. CADe had a higher sessile-serrated lesion detection rate than traditional colonoscopy (4.7% vs 2.0%; P = .01). The improvement in ADR with CADe was significantly higher in the first half of the study (47.2% vs 33.7%; P = .002) compared with the second half (38.7% vs 34.9%; P = .33).

CONCLUSIONS

In a single-center pragmatic RCT, real-time CADe modestly improved ADR and APC in average-detector community endoscopists. (ClinicalTrials.gov number, NCT05963724).

Association between Diverticulosis and Colorectal Neoplasia: Analysis from a Large Austrian Database

Background: Colorectal neoplasia and diverticulosis are common findings on colonoscopies. While adenomas are precursors to colorectal cancer, diverticulosis is usually asymptomatic but can lead to diverticulitis. Despite their prevalence and coexistence, the relationship between these conditions remains unclear. This study investigates whether diverticulosis is associated with adenomas, considering shared risk factors and potential inflammation-driven mechanisms. Methods: We examined 6154 asymptomatic individuals undergoing colorectal cancer screening in Austria. Diverticulosis and colorectal neoplasia were documented during screenings based on macroscopic definitions. Advanced neoplasia was defined as polyps >1 cm or high-grade dysplasia. Associations between diverticulosis and neoplastic findings were assessed using univariate and multivariable logistic regression models. Results: Although the overall incidence of any polypoid lesion was higher in the diverticulosis group (37% vs. 30%), statistical analysis revealed a comparable rate of advanced neoplasms in both groups. Importantly, no significant link between diverticulosis and advanced neoplasms was found (OR 1.125; 95% CI: 0.933 to 1.357, p = 0.218) even after adjusting for confounding factors. In a univariate analysis, a statistically significant association between diverticulosis and the presence of any colorectal polyps was identified (OR 1.388; 95% CI: 1.244-1.549, p < 0.0001). However, after adjusting for confounding factors in model 2 (OR 1.065, 95% CI: 0.942 to 1.204, p = 0.314) and model 3 (OR 1.071, 95% CI: 0.925 to 1.239, p = 0.360), this effect was also not statistically significant. Conclusions: Patients with diverticulosis share demographic and clinical features with those at risk of colorectal neoplasia, such as older age, male gender, and higher cardiometabolic risk. However, diverticulosis does not independently increase the risk of advanced colorectal neoplasia or unspecified polypoid lesions.

Colorectal polyps in young adults: a retrospective review of colonoscopy data from Toowoomba and the Darling Downs

BACKGROUND

Polyps are the predominant precursors of colorectal cancer. In the past three decades, the incidence and mortality rates of colorectal cancer have been increasing in adults younger than 50 years.

AIMS

The aim of this clinical audit was to evaluate the prevalence, characteristics and clinical associations of polyps in adults aged 18-49 years presenting to an established private gastroenterology clinic in the Toowoomba Darling Downs region.

METHODS

The audit included data from 353 patient records held by the Toowoomba Gastroenterology Clinic. Data extracted from patient medical records through the Medical Director program software contained structured endoscopy/colonoscopy and histology reports of excised lesions of patients presenting to the clinic. The extract involved identifying all patients aged 18-49 years in the database from January 2019 to March 2022. Patients were screened based on audit inclusion and exclusion criteria. Patients were risk stratified for recommended surveillance intervals as per Australian Clinical Guidelines.

RESULTS

Of the sample population, 33.4% were identified with polyps and 22.4% were identified with neoplastic polyps (NPs). A total of 6.7% of 18- to 29-year-old patients were identified with intermediate risk for colorectal cancer (CRC) screening, and 19.8% and 19.3% of 30- to 39-year-old and 40- to 49-year-old patients identified with intermediate or high risk for CRC screening respectively. Increased age, greater size of polyps and surveillance of previous polyps were associated with increased NP prevalence.

CONCLUSIONS

Data from this audit supported the temporal trend of increasing prevalence of polyps in adults younger than 50 years. Patient cohorts aged 30-39 and 40-49 years may benefit from earlier first colonoscopies. Findings could be the impetus for future research in young adults presenting for colonoscopy.

Colon Polyp Surveillance: Separating the Wheat From the Chaff

One goal of colorectal cancer (CRC) screening is to prevent CRC incidence by removing precancerous colonic polyps, which are detected in up to 50% of screening examinations. Yet, the lifetime risk of CRC is 3.9%-4.3%, so it is clear that most of these individuals with polyps would not develop CRC in their lifetime. It is, therefore, a challenge to determine which individuals with polyps will benefit from follow-up, and at what intervals. There is some evidence that individuals with advanced polyps, based on size and histology, benefit from intensive surveillance. However, a large proportion of individuals will have small polyps without advanced histologic features (ie, "nonadvanced"), where the benefits of surveillance are uncertain and controversial. Demand for surveillance will further increase as more polyps are detected due to increased screening uptake, recent United States recommendations to expand screening to younger individuals, and emergence of polyp detection technology. We review the current understanding and clinical implications of the natural history, biology, and outcomes associated with various categories of colon polyps based on size, histology, and number. Our aims are to highlight key knowledge gaps, specifically focusing on certain categories of polyps that may not be associated with future CRC risk, and to provide insights to inform research priorities and potential management strategies. Optimization of CRC prevention programs based on updated knowledge about the future risks associated with various colon polyps is essential to ensure cost-effective screening and surveillance, wise use of resources, and inform efforts to personalize recommendations.

The incidence of early onset colorectal cancer in Aotearoa New Zealand: 2000-2020

BACKGROUND

The incidence of early-onset colorectal cancer (EOCRC), diagnosed before age 50, has been rising in many countries in the past few decades. This study aims to evaluate this trend in Aotearoa New Zealand and assess its impact on Māori.

METHODS

Crude incidence and age-standardized incidence of colorectal cancer (CRC) was analyzed from all new cases from the Aotearoa New Zealand national cancer registry for the period 2000-2020. Trends were estimated by sex, ethnicity, age group and location of cancer and projections made to 2040.

RESULTS

Between 2000 and 2020, there were a total of 56,761 cases of CRC diagnosed in Aotearoa New Zealand, 3,702 of these being EOCRC, with age-standardized incidence decreasing significantly (P = 8.2 × 10- 80) from 61.0 to 47.3 cases per 100,000. EOCRC incidence increased on average by 26% per decade (incidence rate ratio (IRR) 1.26, p = < 0.0001) at all sites (proximal colon, distal colon and rectum), while the incidence in those aged 50-79 years decreased on average by 18% per decade (IRR 0.82, p = < 0.0005), again across all sites. There was no significant average change in CRC incidence in those over 80 years. In Māori, there was no significant change in age-standardized incidence. There was however a significant increase in crude incidence rates (IRR 1.28, p = < 0.0005) driven by significant increases in EOCRC (IRR1.36, p = < 0.0005). By 2040, we predict the incidence of EOCRC will have risen from 8.00 to 14.9 per 100,000 (6.33 to 10.00 per 100,000 in Māori). However, due to the aging population an estimated 43.0% of all CRC cases will be diagnosed in those over 80 years of age (45.9% over 70 years of age in Māori).

CONCLUSION

The age-standardized incidence of CRC from 2000 to 2020 decreased in Aotearoa New Zealand, but not for Māori. The incidence of EOCRC over the same period continues to rise, and at a faster rate in Māori. However, with the ageing of the population in Aotearoa New Zealand, and for Māori, CRC in the elderly will continue to dominate case numbers.

Colorectal cancer screening at age 45 years in Israel: Cost-effectiveness and global implications

BACKGROUND

Colorectal cancer (CRC) incidence at ages <50 years is increasing worldwide. Screening initiation was lowered to 45 years in the United States. The cost-effectiveness of initiating CRC screening at 45 years in Israel was assessed with the aim of informing national policy and addressing internationally relevant questions.

METHODS

A validated CRC screening model was calibrated to Israeli data and examined annual fecal immunochemical testing (FIT) or colonoscopy every 10 years from 45 to 74 years (FIT45-74 or Colo45-74) versus from 50 to 74 years (FIT50-74 or Colo50-74). The addition of a fourth colonoscopy at 75 years was explored, subanalyses were performed by sex/ethnicity, and resource demands were estimated.

RESULTS

FIT50-74 and Colo50-74 reduced CRC incidence by 57% and 70% and mortality by 70% and 77%, respectively, versus no screening, with greater absolute impact in Jews/Other versus Arabs but comparable relative impact. FIT45-74 further reduced CRC incidence and mortality by an absolute 3% and 2%, respectively. With Colo45-74 versus Colo50-74, CRC cases and deaths increased slightly as three colonoscopies per lifetime shifted to 5 years earlier but mean quality-adjusted life-years gained (QALYGs) per person increased. FIT45-74 and Colo45-74 cost 23,800-53,900 new Israeli shekels (NIS)/QALYG and 110,600-162,700 NIS/QALYG, with the lowest and highest values among Jewish/Other men and Arab women, respectively. A fourth lifetime colonoscopy cost 48,700 NIS/QALYG. Lowering FIT initiation to 45 years with modest participation required 19,300 additional colonoscopies in the first 3 years.

CONCLUSIONS

Beginning CRC screening at 45 years in Israel is projected to yield modest clinical benefits at acceptable costs per QALYG. Despite different estimates by sex/ethnicity, a uniform national policy is favored. These findings can inform Israeli guidelines and serve as a case study internationally.

Association of KRAS G12C Status with Age at Onset of Metastatic Colorectal Cancer

The association of age at the onset of CRC and the prevalence of a KRAS G12C mutation is unclear. A retrospective, multicenter study evaluating metastatic CRC patients from January 2019 to July 2023, treated at the Oncoclinicas units and tested for tissue based KRAS/NRAS and BRAF mutations in a centralized genomics lab. A mismatch repair (MMR) status was retrieved from different labs and electronic medical records, as were patient demographics (age, gender) and tumor sidedness. The chi-square test was used to examine the association between clinical and molecular variables, with p value < 0.05 being statistically significant. A total of 858 cases were included. The median age was 63.7 years (range 22-95) and 17.4% were less than 50 years old at the diagnosis of metastatic CRC. Male patients represented 50.3% of the population. The sidedness distribution was as follows: left side 59.2%, right side 36.8% and not specified 4%. The prevalence of the KRAS mutation was 49.4% and the NRAS mutation was 3.9%. Among KRAS mutated tumors, the most common variants were G12V (27.6%) and G12D (23.5%), while KRAS G12C was less frequent (6.4%), which represented 3.1% of the overall population. The BRAF mutant cases were 7.3% and most commonly V600E. Only five (<1%) non-V600E mutations were detected. MSI-high or dMMR was present in 14 cases (1.6%). In the age-stratified analysis, left-sidedness (p < 0.001) and a KRAS G12C mutation (p = 0.046) were associated with a younger age (<50 years). In the sidedness-stratified analysis, a BRAF mutation (p = 0.001) and MSI-high/dMMR status (p = 0.009) were more common in right-sided tumors. Our data suggest that KRAS G12C mutations are more frequent in early-onset metastatic CRC. To the best of our knowledge, this is the largest cohort in the Latin American population with metastatic CRC reporting RAS, BRAF and MSI/MMR status.

Esophagogastroscopic Abnormalities Potentially Guided Patients Younger than 50 Years Old to Undergo Colonoscopy Earlier: A Retrospective Cross-Sectional Study

BACKGROUND

The incidence of early-onset colorectal cancer (CRC) is continuously increasing worldwide. Current guidelines in China recommend average-risk individuals starting CRC screening at age 50.

AIMS

To investigate the relationship between the gastric histopathology and colorectal neoplasms to identify CRC risk factors which potentially guide earlier colonoscopy in individuals aged < 50 years.

METHODS

A retrospective cross-sectional study was conducted on 8819 patients younger than age 50 who underwent gastroscopy and colonoscopy simultaneously between November 7, 2020 and November 14, 2022. Multivariate logistic regression was used to evaluate whether various gastric histopathology are risk factors for different types of colorectal polyps, reporting odds ratios (ORs) with corresponding 95% confidence intervals (CIs).

RESULTS

A total of 3390 cases (38.44%) under 50 years old were diagnosed as colorectal polyps. Advanced age (OR 1.66, 95%CI 1.57-1.76), male sex (OR 2.67, 95%CI 2.33-3.08), Helicobacter pylori (H. pylori) infection (OR 1.43, 95%CI 1.24-1.65), gastric polyps (OR 1.29, 95%CI 1.10-1.52), and low-grade intraepithelial neoplasia (LGIN) (OR 2.52, 95%CI 1.39-4.57) were independent risk factors for colorectal adenomas. For non-adenomatous polyps, reflux esophagitis (OR 1.38, 95%CI 1.11-1.71) was also an independent risk factor. Besides, older age (OR 1.90, 95%CI 1.66-2.18), male sex (OR 2.15, 95%CI 1.60-2.87), and H. pylori infection (OR 1.67, 95%CI 1.24-2.24) were associated with a higher risk of advanced neoplasms (advanced adenoma and CRC).

CONCLUSIONS

Earlier colonoscopy for identification and screening may need to be considered for individuals younger than 50 years old with H. pylori infection, LGIN, gastric polyps, and reflux esophagitis. Risk-adapted CRC screening initiation age allows a personalized and precise screening.

Global burden of early-onset colorectal cancer among people aged 40-49 years from 1990 to 2019 and predictions to 2030

PURPOSE

To explore the disease burden of early-onset colorectal cancer (EO-CRC) in individuals aged 40-49 years and provide baseline evidence for routine recommended age adjustment for CRC screening and other clinical decision-making.

METHODS

We collected data stratified by sex, risk factors, and socio-demographic index (SDI) from the Global Burden of Disease Study 2019 Data Resources. Trends in disease burden were analyzed by estimated annual percentage change. The Bayesian age-period-cohort model predicted the burden over the following 10 years.

RESULTS

In 2019, the global rates of incidence, mortality, prevalence, and disability-adjusted life year (DALY) of EO-CRC in people aged 40-44 years were 11.48 (95% uncertainty interval: 10.50-12.59), 4.35 (4.01-4.70), 72.63 (66.48-79.52), 209.82 (193.55-226.59) per 100,000 population. For people aged 45-49 years, the rates of these four estimates were 19.63 (17.97-21.54), 7.76 (7.16-8.41), 121.73 (110.99-133.84), and 335.83 (310.14-362.91), respectively. The incidence and prevalence rates for both age groups increased while the mortality and DALY rates remained stable from 1990 to 2019. In 2019, high-income North America had the highest incidence and prevalence rates. A low milk diet accounted for the largest proportion of global DALYs in EO-CRC, and there was a tendency for the DALY rate first to increase and then decrease with increasing SDI. The incidence and mortality rates were predicted to increase in the next 10 years.

CONCLUSION

The current and future burden of EO-CRC among people aged 40-49 years is heavy. Substantial variation exists in disease burden across regions and countries. Urgent screening actions and policies are needed.

Age-Based Comparative Analysis of Colorectal Cancer Colonoscopy Screening Findings

Background and Objectives: Colorectal cancer (CRC) incidence is rapidly emerging among individuals <50 years, termed as early-onset colorectal cancer (EOCRC). This study aimed to probe variations in tumorigenic pathology and relevant manifestations (polyp and adenoma incidence) between suspected cases of EOCRC and late-onset CRC (LOCRC; ≥50 years of age). Materials and Methods: Between September 2022 and February 2023, colonoscopy-based screening data from 1653 patients were included in this study. All eligible participants were divided into two groups, depending upon patient age, where Group 1 consisted of 1021 patients aged <50 years while Group 2 consisted of 632 patients aged ≥ 50 years. Polyp samples were collected when identified peri-procedurally and characterized according to World Health Organization criteria. Results: Polyp detection rate was 42% for the <50-year age group, while this was 76% for the ≥50-year age group. Additionally, the <50-year age group predominated in hyperplastic polyp manifestation, particularly within the rectum and sigmoid colon. In addition, the ≥50-year age group had increased prevalence of serrated polyps and differing adenoma manifestations. Conclusions: This investigation served to highlight the importance of age stratification for CRC colonoscopy-based screening effectiveness, with particular reference to evaluations that are based on polyp localization within differing colon regions.

Comparing efficacy and factors of postoperative bleeding in endoscopic mucosal resection vs coagulation for intestinal polyps

This study aimed to assess the effectiveness of Endoscopic Mucosal Resection (EMR) and Argon Plasma Coagulation (APC) as therapeutic approaches for intestinal polyps in patients, and to examine the factors associated with postoperative bleeding. This study included 132 patients diagnosed with colorectal polyps (188 polyps) who underwent endoscopic surgery at our hospital between January 2022 and December 2022. Based on the surgical method employed, the patients were divided into 2 groups: EMR (68 cases, 97 polyps) and APC (64 cases, 91 polyps). Comparative analyses were conducted to assess the clinical efficacy, surgery-related indicators, and quality of life the 2 groups. Furthermore, an investigation was carried out to identify the factors associated with postoperative bleeding. The analysis revealed no statistically significant difference in the cure rate of flat and superficial raised polyps between the EMR group and the APC (P > .05). However, it was found that the EMR group exhibited a significantly higher cure rate for subpedunculated and raised-pedunculated polyps compared to the APC group (P < .05). The results of logistics analysis showed that patients with hypertension (OR = 2.876, 95% CI: 1.119-7.393), patients with diabetes (OR = 5.278, 95% CI: 1.388-20.064), patients with hyperlipidemia (OR = 2.594, 95% CI: 1.054-6.380), the polyps of right hemicolon (OR = 2.743, 95% CI: 1.003-7.504), rectal polyps (OR = 5.143, 95% CI: 1.728-7.504), pedunculated polyps (OR = 4.758, 95% CI: 1.322-17.129), adenomatous polyps (OR = 3.152, 95% CI: 1.018-9.757) were independent risk factors for postoperative bleeding in patients with colorectal polyps (P < .05). The findings suggest that for subpedunculated and pedunculated-raised polyps, EMR can be a suitable treatment approach. On the other hand, flat and superficial-raised polyps can be effectively managed with either EMR or APC. The presence of hypertension, diabetes, hyperlipidemia, polyps of the right hemicolon, rectal polyps, pedunculated polyps, and adenomatous polyps has been established as independent risk factors for postoperative bleeding in patients with colorectal polyps.

Delphi Initiative for Early-Onset Colorectal Cancer (DIRECt) International Management Guidelines

BACKGROUND & AIMS

Patients with early-onset colorectal cancer (eoCRC) are managed according to guidelines that are not age-specific. A multidisciplinary international group (DIRECt), composed of 69 experts, was convened to develop the first evidence-based consensus recommendations for eoCRC.

METHODS

After reviewing the published literature, a Delphi methodology was used to draft and respond to clinically relevant questions. Each statement underwent 3 rounds of voting and reached a consensus level of agreement of ≥80%.

RESULTS

The DIRECt group produced 31 statements in 7 areas of interest: diagnosis, risk factors, genetics, pathology-oncology, endoscopy, therapy, and supportive care. There was strong consensus that all individuals younger than 50 should undergo CRC risk stratification and prompt symptom assessment. All newly diagnosed eoCRC patients should receive germline genetic testing, ideally before surgery. On the basis of current evidence, endoscopic, surgical, and oncologic treatment of eoCRC should not differ from later-onset CRC, except for individuals with pathogenic or likely pathogenic germline variants. The evidence on chemotherapy is not sufficient to recommend changes to established therapeutic protocols. Fertility preservation and sexual health are important to address in eoCRC survivors. The DIRECt group highlighted areas with knowledge gaps that should be prioritized in future research efforts, including age at first screening for the general population, use of fecal immunochemical tests, chemotherapy, endoscopic therapy, and post-treatment surveillance for eoCRC patients.

CONCLUSIONS

The DIRECt group produced the first consensus recommendations on eoCRC. All statements should be considered together with the accompanying comments and literature reviews. We highlighted areas where research should be prioritized. These guidelines represent a useful tool for clinicians caring for patients with eoCRC.

Characteristics of adenomatous colorectal polyps among a Saudi population

Objectives

Colorectal cancer is a common cause of cancer-related mortality in KSA with a rising incidence. Although adenomatous polyps are well-recognized as precursors of colorectal cancer, local data are scarce. Therefore, in this study, we aimed to evaluate the characteristics of adenomatous colon polyps in the Saudi population.

Methods

We retrospectively reviewed the electronic databases of all patients who underwent colonoscopy for any indication between January 2015 and December 2019 at a tertiary care hospital. This study included adult patients who were found to have colorectal polyps with identified histopathology reports. We collected clinical and pathological data, including patient age, sex, and histopathological polyp characteristics. A p-value <0.05 was considered significant for descriptive and analytical statistics.

Results

A total of 184 patients with colorectal polyps with identified histopathology reports were included in the analysis. Of these, 130 (70.6%) patients were aged 50 years or older, and 135 (73.3%) were male. Among all polyps, 127 (69%) were adenomatous, 31 (16.8%) were hyperplastic, and 24 (13%) were inflammatory. For adenomatous polyps, 31 (24.4%) were observed in patients younger than 50 years, and high-grade dysplasia was observed in 23 (18%) polyps. Among patients with adenomatous polyps, the anatomical location was as follows: 27 (23%) in the cecum/ascending colon, 12 (9%) in the transverse colon, 45 (35%) in the descending/sigmoid colon, 25 (19%) in the rectum, and 18 (14%) at multiple sites. Age >50 years was significantly associated with adenomatous polyps (P = 0.03).

Conclusion

Approximately one-third of adenomatous polyps were detected proximal to the splenic flexure. Although adenomatous polyps were significantly associated with increasing age, 24% were observed in patients younger than 50 years of age. This finding supports the current recommendation to start screening at the age of 45.

45 Is the new 50: improving colon cancer screening rates

PURPOSE OF REVIEW

The colonoscopy guidelines recently changed to begin screening at age 45. This review discusses the reasons for lowering the age, adenomatous polyp detection rates for patients 45-49, and to discover innovative health education campaigns aimed at younger patients.

RECENT FINDINGS

There are currently approximately 20 million Americans between the age of 45-49 who will need to be screened by gastroenterologists. The prevalence of overall and advanced colorectal neoplasia on screening colonoscopy for average-risk individuals younger than 50 years is 14% and 2%. An important 2022 study using the GI Quality Improvement Consortium Registry demonstrated that patients aged 45-49 had an overall adenoma detection rate of >25%.

SUMMARY

Health education campaigns need to immediately target 20 million Americans to begin colorectal cancer screening. Additional research should focus on whether there are sex differences for adenoma detection rates among patients aged 46-49. Innovative health education campaigns such as "Tune It Up: A Concert To Raise Colorectal Cancer" organized by the American College of Gastroenterology are educating younger patients to begin colorectal screening by combining concerts and health communication.

USPSTF colorectal cancer screening update 2021: A review of evidence

ABSTRACT

The US Preventive Services Task Force recently expanded its colorectal cancer screening recommendations to start screening adults with average risk profile at age 45. In the face of rising healthcare costs, limited medical resources, and in order to facilitate shared decision-making conversations, primary care clinicians should have a thorough understanding of the evidence supporting this new screening guideline.

Adenoma and Sessile Serrated Lesion Detection Rates at Screening Colonoscopy for Ages 45-49 Years vs Older Ages Since the Introduction of New Colorectal Cancer Screening Guidelines

BACKGROUND AND AIMS

All major U.S. guidelines now endorse average-risk colorectal cancer (CRC) screening at 45-49 years of age. Concerns exist that endoscopic capacity may be strained, that low-risk persons may self-select for screening, and that calculations of the adenoma detection rate may be diluted. We analyzed age-specific screening colonoscopy volumes and lesion detection rates before vs after the endorsement of CRC screening at 45-49 years of age.

METHODS

We compared colonoscopy volumes and lesion detection rates in our healthcare system during period 1 (October 2017 to December 2018), before the first change in guidelines, vs period 2 (January 2019 to August 2021), the era of new guidelines.

RESULTS

The proportion of first-time screening colonoscopies performed in 45- to 49-year-olds increased from 3.5% to 11.6% (relative risk, 3.36; 95% CI, 2.45-4.61). The period 2 detection rates for adenoma, advanced adenoma, sessile serrated lesion, advanced sessile serrated lesion, adenomas per colonoscopy, and lesions per colonoscopy were very similar for 45- to 49-year-olds (34.3%, 6.3%, 8.6%, 2.9%, 0.58, and 0.69, respectively) and 50- to 54-year-olds (38.2%, 5.8%, 9.4%, 3.0%, 0.63, and 0.76, respectively) at first-time screening, and for 60- to 64-year-olds at rescreening (33.4%, 6.1%, 7.2%, 2.3%, 0.61, and 0.70, respectively). All detection rates, adenomas per colonoscopy, and lesions per colonoscopy increased from period 1 to period 2 (eg, overall adenoma detection rate 35.1% vs 42.6%; P < .0001), without any decreases among 45- to 49-year-olds.

CONCLUSIONS

In our healthcare system, a lower CRC screening initiation age has modestly affected colonoscopy volume by age without compromising screening yield. Lesion detection rates, including for advanced adenomas, in average-risk 45- to 49-year-olds approximate those in 50- to 54-year-olds at first-time screening and 60- to 64-year-olds at rescreening. National monitoring is needed to assess fully the impact of lowering the CRC screening initiation age.

Colorectal cancer trends in Chile: A Latin-American country with marked socioeconomic inequities

Introduction

Colorectal cancer (CRC) is the third most frequent malignant disease in the world. In some countries with established screening programs, its incidence and mortality have decreased, and survival has improved.

Aims

To obtain reliable data about the epidemiology of CRC in Chile, we analyzed the trends in the last ten years and the influence of observable factors on survival, including a nationwide health program for CRC treatment access (GES program).

Methods

Publicly available data published by the Ministry of Health and National Institute of Statistics were used. Data were obtained from registries of mortality and hospital discharges, making follow-up of the individuals possible. Crude and age-standardized incidence and mortality rates were calculated, and individual survival was studied by constructing Kaplan–Meier curves. Finally, a Cox statistical model was established to estimate the impact of the observable factors.

Results

We found 37,217 newly identified CRC patients between 2008 and 2019 in Chile, corresponding to 103,239 hospital discharges. In the same period, 24,217 people died of CRC. A nearly linear, steady increase in crude incidence, mortality and prevalence was observed. CRC incidence was the lowest in the North of the country, increasing toward the South and reaching a maximum value of 34.6/100,000 inhabitants/year in terms of crude incidence and 20.7/100,000 inhabitants/year in terms of crude mortality in the XII region in 2018. We found that older patients had lower survival rates, as well as men compared to women. Survival was significantly better for patients with private insurance than those under the public insurance system, and the treating hospital also played a significant role in the survival of patients. Patients in the capital region survived longer than those in almost every other part of the country. We found no significant effect on survival associated with the GES program.

Conclusions

We found important inequalities in the survival probabilities for CRC patients in Chile. Survival depends mainly on the type of insurance, access to more complex hospitals, and geographical location; all three factors correlated with socioeconomic status of the population. Our work emphasized the need to create specific programs addressing primary causes to decrease the differences in CRC survival.

Age-Stratified Prevalence and Predictors of Neoplasia Among U.S. Adults Undergoing Screening Colonoscopy in a National Endoscopy Registry

BACKGROUND & AIMS

Several U.S. organizations now recommend starting average-risk colorectal cancer screening at age 45 years, but the prevalence of colonic neoplasia in individuals younger than 50 years has not been well characterized. We used a national endoscopic registry to calculate age-stratified prevalence and predictors of colorectal neoplasia.

METHODS

Outpatient screening colonoscopies performed during 2010-2020 in the GI Quality Improvement Consortium registry were analyzed. We measured the prevalence of advanced neoplasia and adenomas by age, sex, and race/ethnicity, as well as the prevalence ratio of neoplasia compared with the reference group of 50- to 54-year-olds. Multivariable logistic regression models were used to identify predictors of neoplasia.

RESULTS

We identified 3,928,727 screening colonoscopies, of which 129,736 (3.3%) were performed on average-risk individuals younger than 50 years. The prevalence of advanced neoplasia was 6.2% for 50- to 54-year-olds and 5.0% (prevalence ratio, 0.81; 95% confidence interval, 0.78-0.83) for average-risk 45- to 49-year-olds. Men had higher prevalence of neoplasia than women for all age groups. White individuals had higher prevalence of advanced neoplasia than persons of other racial/ethnic groups in most age groups, which was partially driven by serrated lesions. On multivariable regression, White individuals had higher odds of advanced neoplasia than Black, Hispanic, and Asian individuals in both younger and older age groups.

CONCLUSIONS

In a large U.S. endoscopy registry, the prevalence of advanced neoplasia in 45- to 49-year-olds was substantial and supports beginning screening at age 45 years. White individuals had higher risk of advanced neoplasia than Black, Hispanic, and Asian individuals across the age spectrum. These findings may inform adenoma detection benchmarks and risk-based screening strategies.

Colorectal Cancer in Younger Adults

Contrary to decreasing incidence rate of colorectal cancer (CRC) in older adults, incidence rates have nearly doubled in younger adults (age <50 years) in the United States since the early 1990s. A similar increase has been observed across the globe. Despite overall population trends in aging, about 15% of CRCs will be diagnosed in younger adults by 2030. The mechanisms and factors contributing to early-onset CRC (EOCRC) remain puzzling, especially because most young adults diagnosed with CRC have no known risk factors or predisposing conditions, such as family history of CRC or polyps or a hereditary syndrome (eg, Lynch syndrome, polyposis). In this up-to-date review, we discuss the current knowledge of EOCRC, including epidemiology, risk factors, clinical and molecular features, treatment and survival, and recognition and screening strategies.

Prevalence and Predictors of Young-Onset Colorectal Neoplasia: Insights From a Nationally Representative Colonoscopy Registry

BACKGROUND & AIMS

A disturbing increase in early-onset colorectal cancer (EOCRC) has prompted recent guidelines to recommend lowering the colorectal cancer (CRC) screening starting age from 50 to 45 years old for average-risk individuals. Little is known about the prevalence of colorectal neoplasia in individuals between 45 and 49 years old, or even younger, in the United States. We analyzed a large, nationally representative data set of almost 3 million outpatient colonoscopies to determine the prevalence of, and risk factors for, colorectal neoplasia among patients aged 18 to 54.

METHODS

Findings from high-quality colonoscopies were analyzed from AMSURG ambulatory endoscopy centers (ASCs) that report their results in the GI Quality Improvement Consortium (GIQuIC) Registry. Logistic regression was used to identify risk factors for EOCRC.

RESULTS

Increasing age, male sex, White race, family history of CRC, and examinations for bleeding or screening were all associated with higher odds of advanced premalignant lesions (APLs) and CRC. Among patients aged 45 to 49, 32% had any neoplasia, 7.5% had APLs, and 0.58% had CRC. Rates were almost as high in those aged 40 to 44. Family history of CRC portended neoplasia rates 5 years earlier. Rates of APLs were higher in American Indian/Alaskan Natives, but lower among Blacks, Asians, and Hispanics, compared with White counterparts. The prevalence of any neoplasia and APL gradually increased between 2014 and 2019, in all age groups.

CONCLUSIONS

These data provide support for lowering the screening age to 45 for all average-risk individuals. Early messaging to patients and providers in the years leading up to age 45 is warranted, especially in those with a family history of CRC.

Cause, Epidemiology, and Histology of Polyps and Pathways to Colorectal Cancer

Colorectal cancer is the second leading cause of cancer-associated mortality, with a lifetime risk of approximately 4% to 5%. Colorectal cancer develops from the sequential acquisition of defined genetic mutations in the colonic epithelium. Tumorigenesis from normal tissue to cancer occurs largely through 3 pathways: the chromosomal instability pathway, the microsatellite instability pathway, and the sessile serrated pathway. Colorectal cancer incidence and mortality have decreased by approximately 35% since the beginning of screening programs in the 1990s, although other factors such as use of aspirin for coronary disease prevention and decreased smoking rates may also be important. In this review, we discuss the etiology, epidemiology, and histology of colorectal polyps and cancer.

Updates on Age to Start and Stop Colorectal Cancer Screening: Recommendations From the U.S. Multi-Society Task Force on Colorectal Cancer

This document is a focused update to the 2017 colorectal cancer (CRC) screening recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer, which represents the American College of Gastroenterology, the American Gastroenterological Association, and the American Society for Gastrointestinal Endoscopy. This update is restricted to addressing the age to start and stop CRC screening in average-risk individuals and the recommended screening modalities. Although there is no literature demonstrating that CRC screening in individuals under age 50 improves health outcomes such as CRC incidence or CRC-related mortality, sufficient data support the U.S. Multi-Society Task Force to suggest average-risk CRC screening begin at age 45. This recommendation is based on the increasing disease burden among individuals under age 50, emerging data that the prevalence of advanced colorectal neoplasia in individuals ages 45 to 49 approaches rates in individuals 50 to 59, and modeling studies that demonstrate the benefits of screening outweigh the potential harms and costs. For individuals ages 76 to 85, the decision to start or continue screening should be individualized and based on prior screening history, life expectancy, CRC risk, and personal preference. Screening is not recommended after age 85.

Updates on Age to Start and Stop Colorectal Cancer Screening: Recommendations From the U.S. Multi-Society Task Force on Colorectal Cancer

This document is a focused update to the 2017 colorectal cancer (CRC) screening recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer, which represents the American College of Gastroenterology, the American Gastroenterological Association, and the American Society for Gastrointestinal Endoscopy. This update is restricted to addressing the age to start and stop CRC screening in average-risk individuals and the recommended screening modalities. Although there is no literature demonstrating that CRC screening in individuals under age 50 improves health outcomes such as CRC incidence or CRC-related mortality, sufficient data support the U.S. Multi-Society Task Force to suggest average-risk CRC screening begin at age 45. This recommendation is based on the increasing disease burden among individuals under age 50, emerging data that the prevalence of advanced colorectal neoplasia in individuals ages 45 to 49 approaches rates in individuals 50 to 59, and modeling studies that demonstrate the benefits of screening outweigh the potential harms and costs. For individuals ages 76 to 85, the decision to start or continue screening should be individualized and based on prior screening history, life expectancy, CRC risk, and personal preference. Screening is not recommended after age 85.

Updates on age to start and stop colorectal cancer screening: recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer

This document is a focused update to the 2017 colorectal cancer (CRC) screening recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer, which represents the American College of Gastroenterology, the American Gastroenterological Association, and the American Society for Gastrointestinal Endoscopy. This update is restricted to addressing the age to start and stop CRC screening in average-risk individuals and the recommended screening modalities. Although there is no literature demonstrating that CRC screening in individuals under age 50 improves health outcomes such as CRC incidence or CRC-related mortality, sufficient data support the U.S. Multi-Society Task Force to suggest average-risk CRC screening begin at age 45. This recommendation is based on the increasing disease burden among individuals under age 50, emerging data that the prevalence of advanced colorectal neoplasia in individuals ages 45 to 49 approaches rates in individuals 50 to 59, and modeling studies that demonstrate the benefits of screening outweigh the potential harms and costs. For individuals ages 76 to 85, the decision to start or continue screening should be individualized and based on prior screening history, life expectancy, CRC risk, and personal preference. Screening is not recommended after age 85.

Advances in Understanding Early-Onset Colorectal Cancer

Since the 1990s, the incidence of early-onset colorectal cancer (at <50 years of age) in the US has increased by more than 50%; similar increases have also been observed internationally. These increases are found particularly among individuals born during and after the 1960s, raising the possibility that the increased rates of early-onset colorectal cancer are attributable to changes in risk-factor patterns throughout successive generations. The reasons for these alarming epidemiologic patterns for early-onset colorectal cancer worldwide are only recently being investigated and major gaps in our knowledge remain. In the current issue of this journal, Arif and colleagues differentiated characteristics and outcomes of early-onset colorectal cancer in patients with the predisposing conditions of inflammatory bowel disease or hereditary genetic syndromes, compared with patients who have sporadic disease. Also, in this issue, Schumacher and colleagues investigated risk factors for early-onset colorectal adenocarcinoma in a nested case-control study among Kaiser Permanente Southern California (KPSC) health plan members. The research presented on characteristics and outcomes points to the importance of sporadic disease in the rise of early-onset colorectal cancer, while the research presented on risk factors points to the importance of obesity as a potential explanatory factor for this rise.See related articles by Arif et al., p. 1785 and by Schumacher et al., p. 1792.