Prevalence of and Risk Factors for Colorectal Neoplasia in Asymptomatic Young Adults (20-39 Years Old)

Comparison analysis of the burden and attributable risk factors of early-onset and late-onset colorectal cancer in China from 1990 to 2019

OBJECTIVES

The project intended to analyze the impact of burden and related risk factors of late-onset colorectal cancer (LOCRC) and early-onset colorectal cancer (EOCRC) in China, thus offering essential references for optimizing prevention and control strategies.

METHOD

Global Burden of Disease Study was employed to describe burden changes of EOCRC and LOCRC in China during 1990-2019, containing the numbers of incidence, deaths, prevalence, and disability-adjusted life years (DALYs), and to compare attributable deaths and DALYs risk factors in varying age and sex segments.

RESULTS

The numbers and corresponding crude rates of incidence, deaths, prevalence, and DALYs of EOCRC and LOCRC in China during 1990-2019 demonstrated an upward trend across all age categories, with males being dramatically predominant. Overall, over time, the impact of a low-calcium diet and a low-fiber diet on mortality and DALY rates decreased, while the impact of other risk factors increased. In terms of gender, the risk factors affecting males changed greatly, with smoking, inadequate milk intake, and the low whole-grain diet being the main factors in 2019, while in 1990, the main factors were the low-calcium diet, smoking, and inadequate milk intake.

CONCLUSION

The burden of colorectal cancer in China is concerning. Patients grouped by diagnostic age exhibit different characteristics, indicating the need for high-quality research in the future to achieve personalized medicine tailored to different population characteristics.

Brief Report: Trends in Incidence, Mortality, and Disability-Adjusted Life Years for Early-Onset Colorectal Cancer in Canada Between 1990 and 2019

BACKGROUND

Colorectal cancer is the third most common malignancy globally. Early-onset colorectal cancer (EOCRC) is becoming a growing healthcare focus globally, particularly in North America. We estimated trends in incidence, mortality, and disability-adjusted life years (DALYs) for EOCRC in Canada between 1990 and 2019.

METHODS

We used the Global Burden of Diseases Study to evaluate trends in incidence, mortality, and DALYs for EOCRC in Canada between 1990 and 2019. Rates were estimated per 100,000 persons at risk with associated uncertainty intervals (UIs). Annual percentage changes (APC) were estimated using joinpoint regression with 95% confidence intervals (CIs).

RESULTS

In 2019, the incidence, mortality, and DALYs rates for EOCRC were 10.89 (95% UI 8.09, 14.34), 2.24 (95% UI 2.00, 2.51), and 111.37 (95% UI 99.34, 124.78) per 100,000 individuals, respectively. Incidence increased during the study period by 1.12%/year (95% CI 1.03%, 1.22%; p < 0.001). The largest increase in incidence in EOCRC occurred between 1990 and 2007, with an APC of 2.23% (95% CI 2.09%, 2.37%; p < 0.001). Mortality (APC 2.95%, 95% CI 1.89%, 4.02%; p < 0.001) and DALY (APC 2.96%, 95% CI 1.84%, 4.09%; p < 0.001) rates increased for males between 2001 and 2006.

CONCLUSIONS

Our study reveals a substantial burden in EOCRC in Canada, with a significant increase in incidence.

Factors Affecting Cancer Mortality in Young Adults: Findings from a Prospective Cohort Study

BACKGROUND/OBJECTIVES

Cancer incidence in young adults or those aged 15-49 years old has increased during the past decade. Knowledge about the risk factors for cancer-related deaths in young adults is limited, particularly in low- and middle-income countries (LMICs).

METHODS

This analysis was based on the Hanoi Prospective Cohort Study, an ongoing study of 39,401 participants aged 15 or older in Northern Vietnam in the 2007-2019 period. A Cox proportional hazard regression model was used to calculate the hazard ratio (HR) and 95% confidence intervals (95% CIs) for the association between potential factors and the risk of cancer-related deaths.

RESULTS

With a median follow-up of 11.01 years, we identified 164 deaths in young adults out of 554 total deaths. Overall, family history of cancer (HR = 7.34; 95% CI: 3.30-16.36), drinking alcohol (HR = 1.82; 95% CI: 1.18-2.81), and smoking (HR = 2.22; 95% CI: 1.36-3.63) were found to be risk factors, while drinking coffee was found to be a protective factor (HR = 0.49; 95% CI: 0.24-1.00) for cancer-related deaths in young adults. Young male adults were found to be at a higher risk due to excessive cigarette smoking (HR = 1.91; 95% CI: 1.00-3.68) and alcohol consumption (HR = 2.15; 95% CI: 1.32-3.53) than those aged 50 years and older (HR = 1.36 and 95% CI: 0.96-1.93 and 1.27 and 95% CI: 0.97-1.67, respectively). The risk of death from cancer in women compared with men in the young population was twice as high as that in the older population (HR = 1.18 and 95% CI: 0.72-1.94 vs. 0.47 and 95% CI: 0.35-0.63, respectively).

CONCLUSIONS

Our data suggest that the young Vietnamese population is vulnerable to the risk of cancer-related deaths and that cancer in women will increase rapidly in the future.

Early Onset Colorectal Cancer: Molecular Underpinnings Accelerating Occurrence

The onset of colorectal cancer (CRC) in patients younger than 50 continues to rapidly increase. This study highlights the epidemiologic changes, risk factors, clinical characteristics, and molecular profiles prevalent in early onset CRC patients, and identifies key areas for future research. It has been noted that only a small fraction of early onset CRC cases is attributed to known hereditary mutations and fit the canonical pathway of late-onset colorectal cancer development. To highlight this, we review the genetic and epigenetic modifications specific to early onset CRC. We also discuss the synergetic effect of single-nucleotide polymorphisms and environmental factors on the early onset of CRC. Additionally, we discuss the potential of noninvasive biomarker assays to enhance early detection, screening, diagnosis, and prognostic outcome predictions.

Early-Onset colorectal Cancer: From the laboratory to the clinic

Colorectal cancer that occurs before age of 50 is defined as Early-Onset Colorectal Cancer (EOCRC). Its incidence has worryingly increased since the late 90 s and is expected to keep rising in the next future, despite Late-Onset CRC (LOCRC) is decreasing worldwide. Because of this, there is an urgent need to better understand this subset of patients in order to give them the best treatment possible. However, most of the literature is retrospective and often discordant. In this review, we aim to provide a general overview of the issue, endeavoring to highlight the current available knowledge. We decided to move from the beginning, investigating risk factors and inheritance, passing through diagnosis and clinical aspects, and to conclude with the translational part, focusing on the biology of the tumor. However, lot of questions remain open, including screening age and prognosis. Indeed, young patients tend to be treated more aggressively, even if a survival benefit has not been proven yet. Every clinician should be aware of the best practice for young people, and more translational studies are awaited in order to clarify is EOCRC represents a distinct biological entity.

Risk factors for early-onset colorectal cancer: A Canadian prospective cohort study

PURPOSE

The incidence of early-onset (<50 years of age) colorectal cancer (eoCRC) has been steadily increasing in high-income countries including Canada. Despite this increase in incidence, the etiology of eoCRC remains unclear and prospective cohort studies of potential risk factors are limited.

METHODS

We examined two prospective cohorts of healthy individuals (<50 years of age) who completed baseline questionnaires in the Ontario Health Study and Alberta's Tomorrow Project. We examined the associations between demographic characteristics, chronic health conditions, and lifestyle behaviours with the development of eoCRC using Cox proportional hazard models. Cohorts were analyzed separately and hazard ratios for each risk factor were pooled with random effects meta-analyses.

RESULTS

During an average follow-up of 6.63 years, 98 eoCRC cases occurred among study participants (n=127,852). A family history of CRC alone or with a history of other cancer types was associated with an increased risk of developing eoCRC (HR: 2.76, 95% CI: 1.43-5.32), but a family history of a non-CRC cancer only was not (HR: 1.18, 95% CI: 0.61-2.30). Heavy smokers (≥ 10 pack-years) at baseline had a higher risk of eoCRC compared to non-smokers (HR: 1.87, 95% CI: 1.00-3.52). Sex, socioeconomic factors, diabetes, alcohol consumption, among other factors were not significantly associated with the risk of eoCRC.

CONCLUSION

Our findings indicate that specific CRC risk factors are also associated with developing eoCRC. The data in the study offers valuable insights that could be integrated in future meta-analyses. Additional prospective cohort studies are required to understand the etiology of eoCRC.

Birth Cohort Colorectal Cancer (CRC): Implications for Research and Practice

Colorectal cancer (CRC) epidemiology is changing due to a birth cohort effect, first recognized by increasing incidence of early onset CRC (EOCRC, age <50 years). In this paper, we define "birth cohort CRC" as the observed phenomenon, among individuals born 1960 and later, of increasing CRC risk across successive birth cohorts, rising EOCRC incidence, increasing incidence among individuals aged 50 to 54 years, and flattening of prior decreasing incidence among individuals aged 55 to 74 years. We demonstrate birth cohort CRC is associated with unique features, including increasing rectal cancer (greater than colon) and distant (greater than local) stage CRC diagnosis, and increasing EOCRC across all racial/ethnic groups. We review potential risk factors, etiologies, and mechanisms for birth cohort CRC, using EOCRC as a starting point and describing importance of viewing these through the lens of birth cohort. We also outline implications of birth cohort CRC for epidemiologic and translational research, as well as current clinical practice. We postulate that recognition of birth cohort CRC as an entity-including and extending beyond rising EOCRC-can advance understanding of risk factors, etiologies, and mechanisms, and address the public health consequences of changing CRC epidemiology.

Metabolic syndrome and risk of colorectal cancer: A Mendelian randomization study

Background

Observational studies have previously demonstrated a significant relationship among both metabolic syndrome (Mets) and colorectal cancer (CRC). Whether there is a causal link remains controversial.

Objective

To clarify whether Mets and their components have a causal effect on colorectal cancer, we have carried out a bidirectional Mendelian randomization analysis (MR).

Methods

This study started from genome-wide association data for Mets and its 5 components (hypertension, waist circumference, fasting blood glucose, serum triglycerides, and serum high-density lipoprotein cholesterol) and colorectal cancer. Mendelian randomization (MR) techniques were used in the study to examine their associations.

Results

After Benjamini-Hochberg multiple corrections, genetically predicted significant causal link exists between WC (waist circumference) and CRC. The OR was 1.35 (95 % CI: 1.08-1.69; p = 0.0096). Other Mets components (HBP, FBG, TG, HDL), on the other hand, found no evidence of a genetic link between CRC and Mets. In addition, MR results showed that CRC was not causally related to either Mets or the components. We get the same result in the validated dataset.

Conclusion

According to the bidirectional MR investigation shows a significant causal relationship among obesity and CRC in the Mets component but no causal relationship in the opposite direction.

Association of High Body Mass Index in Early Life With the Development of Colorectal Cancer

SIGNIFICANCE

This study on the relationship between early life high BMI and the development of CRC reveals the role of high BMI during childhood and adolescence in the occurrence and progression of CRC. It suggests the importance of restoring normal weight or reducing weight in individuals with high BMI early in life for the prevention of colorectal cancer.

Age- and sex-stratified detection rates and associated factors of colorectal neoplasia in the Tianjin colorectal cancer screening program from 2012 to 2020

PURPOSE

Colorectal cancer (CRC) screening has been implemented in Tianjin, China since 2012. The objective was to estimate the neoplasia detection rate in a high-risk population by age and sex and to investigate the potential factors associated with colorectal neoplasia.

PATIENTS AND METHODS

This study is based on data of the Tianjin CRC screening program from 2012 to 2020. Residents with a positive high-risk factors questionnaire (HRFQ) or a positive faecal immunochemical test (FIT) were identified as high-risk participants and were subsequently recommended for a free colonoscopy.

RESULTS

A total of 4,117,897 eligible participants aged 40-74 years completed both a HRFQ and FIT, and 217,164 (5.3%) of them were identified as high-risk participants. Positive rates of preliminary screening increased with age and were higher in females than in males. For 57,971 participants undertaking colonoscopy, the detection rates of nonadvanced adenoma, advanced adenoma and CRC were 37.8%, 5.7% and 1.6%, respectively. Detection rates of advanced neoplasia increased from the age of 50 and were higher in males. For nonadvanced neoplasia, a strong increase was observed in males from the age of 40 and in females from the age of 50. Male sex had a greater impact on individuals aged 40-49 than on older individuals. Several factors including current smoking, drinking, and higher body mass index (BMI) were significantly associated with the presence of neoplasia, whereas, these associations were mainly restricted to individuals aged above 50 but not those aged 40-49 years.

CONCLUSIONS

These findings support that age-specific risk stratification and sex-specific initiating ages for CRC screening should be recommended to improve the accuracy and effectiveness of current screening strategy.

Summary and comparison of recently updated post-polypectomy surveillance guidelines

Recently, updated guidelines for post-polypectomy surveillance have been published by the U.S. Multi-Society Task Force (USMSTF), the British Society of Gastroenterology/Association of Coloproctology of Great Britain and Ireland/Public Health England (BSG/ACPGBI/PHE), the European Society of Gastrointestinal Endoscopy (ESGE), the Japan Gastroenterological Endoscopy Society (JGES), and the Korean Multi-Society Taskforce Committee. This review summarizes and compares the updated recommendations of these 5 guidelines. There are some differences between the guidelines for the recommended post-polypectomy surveillance intervals. In particular, there are prominent differences between the guidelines for 1-4 tubular adenomas < 10 mm with low-grade dysplasia (nonadvanced adenomas [NAAs]) and tubulovillous or villous adenomas. The USMSTF, JGES, and Korean guidelines recommend colonoscopic surveillance for patients with 1-4 NAAs and those with tubulovillous or villous adenomas, whereas the BSG/ACPGBI/PHE and ESGE guidelines do not recommend endoscopic surveillance for such patients. Surveillance recommendations for patients with serrated polyps (SPs) are limited. Although the USMSTF guidelines provide specific recommendations for patients who have undergone SPs removal, these are weak and based on very lowquality evidence. Future studies should examine this topic to better guide the surveillance recommendations for patients with SPs. For countries that do not have separate guidelines, we hope that this review article will help select the most appropriate guidelines as per each country's healthcare environment.

Global trends in incidence, death, burden and risk factors of early-onset cancer from 1990 to 2019

Objective

This study aimed to explore the global burden of early-onset cancer based on the Global Burden of Disease (GBD) 2019 study for 29 cancers worldwid.

Methods and analysis

Incidence, deaths, disability-adjusted life years (DALYs) and risk factors for 29 early-onset cancer groups were obtained from GBD.

Results

Global incidence of early-onset cancer increased by 79.1% and the number of early-onset cancer deaths increased by 27.7% between 1990 and 2019. Early-onset breast, tracheal, bronchus and lung, stomach and colorectal cancers showed the highest mortality and DALYs in 2019. Globally, the incidence rates of early-onset nasopharyngeal and prostate cancer showed the fastest increasing trend, whereas early-onset liver cancer showed the sharpest decrease. Early-onset colorectal cancers had high DALYs within the top five ranking for both men and women. High-middle and middle Sociodemographic Index (SDI) regions had the highest burden of early-onset cancer. The morbidity of early-onset cancer increased with the SDI, and the mortality rate decreased considerably when SDI increased from 0.7 to 1. The projections indicated that the global number of incidence and deaths of early-onset cancer would increase by 31% and 21% in 2030, respectively. Dietary risk factors (diet high in red meat, low in fruits, high in sodium and low in milk, etc), alcohol consumption and tobacco use are the main risk factors underlying early-onset cancers.

Conclusion

Early-onset cancer morbidity continues to increase worldwide with notable variances in mortality and DALYs between areas, countries, sex and cancer types. Encouraging a healthy lifestyle could reduce early-onset cancer disease burden.

Causes and Prevention of Early-Onset Colorectal Cancer

Sporadic colorectal cancer (CRC) has historically been considered a disease of the elderly. However, early-onset colorectal cancer (eoCRC) incidence and prevalence have steadily increased over the last few decades, highlighting the critical need for a comprehensive understanding of its causes and prevention. This research examines the numerous factors contributing to the increasing incidence of eoCRC. These factors include a combination of genetic predispositions and environmental effects. We also investigate the impact of modifiable lifestyle factors like obesity, physical inactivity, and an unhealthy diet on eoCRC risk. Understanding these factors is critical in developing future diagnostic, prognostic, disease monitoring, and therapy planning strategies in managing eoCRC and will help optimize guidelines for CRC screening.

Burden of early-onset colorectal cancer along with attributable risk factors from 1990 to 2019: a comparative study between China and other G20 countries

PURPOSE

The credible data about the burden of early-onset colorectal cancer (EOCRC) in China when compared to other countries in the group of twenty (G20) remained unavailable. We aimed to assess the burden and trends of EOCRC and attributable risk factors in China. Meanwhile, the comparison in the burden and attributable risk factors between China and other G20 countries was also evaluated.

METHODS

Data on the incidence, prevalence, mortality, disability-adjusted life years (DALYs), and attributable risk factors of EOCRC in China were obtained from Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 and compared with other G20countries. Temporal trends of age-standardized rates for incidence, prevalence, mortality, and DALYs were evaluated by estimated annual percentage change (EAPC). The autoregressive integrated moving average (ARIMA) model was used to forecast the incidence, mortality, and DALY rates of EOCRC in China from 2020 to 2029.

RESULTS

From 1990 to 2019, the age-standardized incidence rate (ASIR) and age-standardized prevalence rate (ASPR) of EOCRC in China increased with the EAPCs of 4.61 [95% confidence interval (CI): 4.45-4.77] and 5.82 (95% CI: 5.60-6.05). When compared to G20 countries, China was ranked 13^th in the ASIR in 1990 and then increased to 2^nd in 2019, second only to Japan. The ASPRs increased in all G20 countries, being highest in Saudi Arabia, followed by China and Mexico. Moreover, China had the highest age-standardized mortality rate and highest age-standardized DALY rate in 2019. In China, the five leading risk factors, for both sexes, were diet low in milk [18.54% (95% UI: 12.71-24.07)], diet low in calcium [15.06% (95% UI: 10.70-20.03)], alcohol use [12.16% (95% UI: 8.87-15.64)], smoking [9.08% (95% UI: 3.39-14.11)], and diet high in red meat [9.08% (95% UI: 3.39-14.11)] in 2019. Over the next 10 years, ASIR, ASMR, and age-standardized DALY rate of EOCRC will increase continuously in males and females.

CONCLUSION

The burden of EOCRC in China and other G20 countries is worrisome, indicating that coordinated efforts are needed to conduct high-quality researches, allocate medical resources, adjust screening guidelines, and develop effective treatment and prevention strategies in the G20 countries.

Smoking as a risk factor for colorectal neoplasms in young individuals? A systematic meta-analysis

BACKGROUND AND AIMS

Early-onset colorectal neoplasms (EoCRN) include both benign and malign colorectal tumors, which occur before the age of 50. The incidence of EoCRN is rising worldwide. Tobacco smoking has previously been proven to be related to the development of various tumor types. However, its relationship with EoCRN is not clearly defined. Hence, we carried out a systematic review and a meta-analysis to evaluate the relationship between smoking status and the risk of EoCRN.

METHODS

A systematic search of PubMed, EMBASE, and Web of Science up to September 7, 2022, was performed for studies that evaluated the association of smoking status with EoCRN. The quality of the case-control study was evaluated with the Newcastle‒Ottawa Scale. The quality of the cross-sectional studies was evaluated with the American Health Care Research and Quality checklist. Fixed-effects models were used to pool odds ratios (ORs) to evaluate the relationship between the risk of developing EoCRN and smoking status. The meta-analyses were performed with Review Manager version 5.4, and funnel plots and publication bias tests were produced by STATA software.

RESULTS

A total of six studies were included in this meta-analysis. After pooling the results of these six studies, we found that current smokers carry a relatively high risk of developing EoCRN (OR, 1.33; 95% confidence interval [CI], 1.17-1.52) compared to never-smokers. Ex-smokers were not at a significantly increased risk for developing EoCRN (OR, 1.00; 95% CI, 0.86-1.18).

DISCUSSION

Smoking behavior is significantly associated with an increased risk for developing EoCRN and might be one of the reasons for the increasing incidence. Ex-smokers who quit are not at significant risk of developing EoCRN.

Predictors for Colorectal Polyps in an Asymptomatic Population Undergoing Medical Check-ups

BACKGROUND

Colorectal cancer primarily arises from colorectal polyps. Early screening and removal is beneficial, especially in asymptomatic populations. This research aimed to reveal the risk factors detected in medical check-ups for colorectal polyps in asymptomatic people.

MATERIALS AND METHODS

Clinical data of 933 asymptomatic people who underwent colonoscopies from May 2014 to December 2021 was analyzed retrospectively. Data included sex, age, colonoscopy findings, polyp pathology, polyp number, and blood test results. The distribution of colorectal lesions was analyzed. Participants were divided into control and polyp groups, adenomatous and non-adenomatous polyp groups, and single and multiple adenoma groups.

RESULTS

Participants' age, proportion of males, carcinoembryonic antigen (CEA), uric acid and glycosylated hemoglobin levels were significantly higher ( P ≤0.05) in the polyp group. Age (>40 y), sex (male), and CEA level (>1.435 ng/mL) were independent risk factors for polyps. CEA, uric acid, carbohydrate antigen 19-9, triglyceride, and total cholesterol levels were significantly higher ( P <0.05) in the adenoma group than in the non-adenomatous group. CEA level (>1.435 ng/mL) was an independent predictor for adenomas ( P <0.05). Participants' age, proportion of males, CEA, glycosylated hemoglobin, and fasting blood glucose levels were significantly higher ( P <0.05) in the multiple adenoma group than in the single group; the high-density lipoprotein cholesterol level was lower ( P <0.05). No independent risk factors were found for the number of adenomas.

CONCLUSIONS

Serum CEA level (>1.435 ng/mL) was independent risk factor for colorectal polyps. It may be conducive to improve discriminative ability of colorectal cancer risk stratification model.

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.

Elucidating the Drivers for the Rising Incidence of Early-Onset Colorectal Cancer: How Ecologic Studies Could Help and What Is Next

The incidence of colorectal cancer diagnosed before age 50, often referred to as early-onset colorectal cancer, has been increasing, whereas the overall colorectal cancer incidence has declined. Elucidating the drivers for the rising burden of early-onset colorectal cancer is a priority in cancer epidemiology and prevention. In this issue of Cancer Epidemiology, Biomarkers & Prevention, Chen and colleagues demonstrated that ecologic studies are a helpful method to reveal emerging risk factors at the population level and concluded that alcohol use might be a potential contributor to the rising incidence of early-onset colorectal cancer. Moving forward, because of the observed birth cohort effect in early-onset colorectal cancer, where younger generations have a steeper increase, hypothesis-driven investigations on emerging risk factors in recent generations, especially during early life, are warranted. Ultimately, the identified risk factors could be integrated with well-established microsimulation models of colorectal cancer, powerful tools that can simultaneously capture population-level secular changes in risk factors, relative risk estimates for each risk factor, and the natural history of colorectal cancer. This would allow us to quantitatively estimate the explained and unexplained portion of the rising incidence of early-onset colorectal cancer by calendar period and birth cohorts, and to help identify priorities in etiologic research, prevention, and early detection. See related article by Chen et al., p. 217.

Young Patients With Colorectal Cancer Have Higher Early Mortality but Better Long-Term Survival

INTRODUCTION

To define the prognosis of colorectal cancer (CRC) in young patients and to compare their postoperative treatment with that of older patients.

METHODS

This multicenter study enrolled 5,457 patients with primary CRC who underwent surgical resection. The overall survival (OS), clinicopathologic characteristics, and postoperative treatment of 253 young patients aged 18-44 years and 5,204 older patients aged 44-80 years were analyzed.

RESULTS

The OS rate was 77.1% for young and 74.2% for older patients (P = 0.348). Landmark analysis showed a significant difference in survival between young and older patients, with 63.8% of deaths among young patients being within 25 months of surgery compared with 42.4% among older patients (P = 0.002). Among those who survived more than 25 months, young patients had significantly better survival than older patients (P = 0.009). Multivariable analysis of young patients revealed that the tumor location, perineural invasion, and stage were associated with poor survival within 25 months; after this period, stage was the only prognostic marker. Young patients were more likely to receive chemotherapy, particularly multiagent regimens. For young patients, no significant difference in OS was found based on the chemotherapy regimen, regardless of disease stage (II, III, or IV, all P > 0.05). In addition, unlike in older patients, no difference in OS was found in young patients regardless of the drug regimen administered (all P > 0.05).

DISCUSSION

Young-onset CRC may have a unique disease biology that warrants further research and therapy development.

Is early-onset cancer an emerging global epidemic? Current evidence and future implications

Over the past several decades, the incidence of early-onset cancers, often defined as cancers diagnosed in adults <50 years of age, in the breast, colorectum, endometrium, oesophagus, extrahepatic bile duct, gallbladder, head and neck, kidney, liver, bone marrow, pancreas, prostate, stomach and thyroid has increased in multiple countries. Increased use of screening programmes has contributed to this phenomenon to a certain extent, although a genuine increase in the incidence of early-onset forms of several cancer types also seems to have emerged. Evidence suggests an aetiological role of risk factor exposures in early life and young adulthood. Since the mid-20th century, substantial multigenerational changes in the exposome have occurred (including changes in diet, lifestyle, obesity, environment and the microbiome, all of which might interact with genomic and/or genetic susceptibilities). However, the effects of individual exposures remain largely unknown. To study early-life exposures and their implications for multiple cancer types will require prospective cohort studies with dedicated biobanking and data collection technologies. Raising awareness among both the public and health-care professionals will also be critical. In this Review, we describe changes in the incidence of early-onset cancers globally and suggest measures that are likely to reduce the burden of cancers and other chronic non-communicable diseases.

Young-Onset Colon Cancer: A Case Report

Colorectal cancer (CRC) which is diagnosed in patients under the age of 50 years is defined as young-onset CRC. There has been a substantial increase in the incidence and mortality of young-onset CRC in the past four decades and the patients have delayed diagnoses leading to the advanced stages of CRC at the time of diagnosis. Here we present a case of a 34-year-old male patient with colon cancer and a literature review on young-onset colon cancer to highlight the age-related disparities in CRC incidence and try to explore the possible causative factors for the rise in incidence and mortality in young patients due to CRC.

Factors associated with the risk of colorectal neoplasia in young adults under age 40

BACKGROUND/AIMS

Recent epidemiologic studies have shown a continued increase in colorectal cancer incidence among younger adults. Little is known about the factors that contribute to the development of young-onset colorectal neoplasia (CRN).

METHODS

A cross-sectional analysis was performed for individuals younger than 40 years who underwent colonoscopy in Seoul St. Mary's Hospital and its affiliated health screening center. High-risk CRN was defined as adenoma or sessile serrated lesion ≥ 10 mm, with three or more adenomas, villous histology, high grade dysplasia, or carcinoma.

RESULTS

Of these 13,621 included participants, 2,023 (14.9%) had one and more CRN. Young patients with CRN tended to be elderly, male, obese, smoker, having a habit of drinking, and having comorbidities such as hypertension, dyslipidemia, diabetes, and chronic kidney disease. In a multivariate analysis adjusted for age, sex, obesity, smoking status, and alcohol intake, old age (odds ratio [OR], 1.086; 95% confidence interval [CI], 1.054 to 1.119), male sex (OR, 1.748; 95% CI, 1.247 to 2.451), obesity (OR, 1.439; 95% CI, 1.133 to 1.828), and smoking (OR, 1.654; 95% CI, 1.287 to 2.127) were independent risk factors for overall CRN. Obesity and smoking as two modifiable factors increased the risk for high-risk CRN even more than for overall CRN (OR, 1.734; 95% CI, 1.168 to 2.575 and OR, 1.797; 95% CI, 1.172 to 2.753, respectively).

CONCLUSION

Obesity and smoking were modifiable risk factors for CRN in young adults. They increased the risk for highrisk CRN even more than for overall CRN. A colonoscopy might be beneficial for young individuals with these factors.

The Burden of Early-Onset Colorectal Cancer and Its Risk Factors from 1990 to 2019: A Systematic Analysis for the Global Burden of Disease Study 2019

Simple Summary

In this cross-sectional study, the global incidence, death, and DALY rates of early-onset colorectal cancer (CRC) increased from 1990 to 2019, with large variations in the regional and national levels. A low-milk or low-calcium diet and alcohol use were the leading possible risk factors in 2019. The importance of high body mass index and high fasting plasma glucose increased among both males and females from 1990 to 2019, while the importance of smoking and a low-fiber diet decreased among both sexes, but especially among females. These findings provide policymakers with an accurate quantification of the burden of early-onset CRC, and may help to identify and target high-risk individuals to mitigate the burden of early-onset CRC.

Abstract

Background: The incidence of early-onset colorectal cancer (CRC) diagnosed before age 50 has been increasing over the past decades. Hence, we examined the global, regional, and national burden of early-onset CRC and its risk factors from 1990 to 2019. Methods: Using data from the Global Burden of Disease (GBD) Study 2019, we reported the incidence, deaths, and disability-adjusted life-years (DALYs) attributable to the risk factors of early-onset CRC. All estimates were reported with 95% uncertainty intervals (UIs). Results: The global numbers of early-onset CRC for incidence, deaths, and DALYs in 2019 were 225,736 (95% UI, 207,658 to 246,756), 86,545 (80,162 to 93,431), and 4,259,922 (3,942,849 to 4,590,979), respectively. Despite large variations at the regional and national levels, the global incidence rate, death rate, and DALY rate increased from 1990 to 2019. Diets low in milk, diets low in calcium, and alcohol use were the leading risk factors in 2019. From 1990 to 2019, a high body mass index and high fasting plasma glucose ranked remarkably higher among males and females, while smoking and diets low in fiber ranked lower among both sexes, with a more profound change among females. Conclusions: Despite large variations in regional and national levels, the global incidence rate, death rate, and DALY rate increased during the past three decades. These findings may provide policymakers with an accurate quantification of the burden of early-onset CRC and targeted identification of those most at risk to mitigate the burden of early-onset CRC.

Prevalence and risk of colorectal polyps among the Korean population under 50 years

Colorectal cancer is a common cancer; generally, adults aged ≥ 50 years are screened using stool occult blood tests and colonoscopy. However, colorectal adenoma and cancer have been found in patients under the aged of 50, and studies on characteristics and risk factors in young patients are lacking. We evaluated the prevalence and risk factors of colorectal adenoma and cancer in young adults aged under 50 years. We retrospectively analyzed 570 individuals aged under 50 years who underwent colonoscopy at the Haeundae Paik Hospital, Korea, from January to June 2018. Logistic regression model was used to identify the risk factors for colorectal adenoma and colorectal cancer. The prevalence of colorectal adenoma in group of 19-29 years was 3.2% (1 of 31), 30-39 years was 13.8% (30 of 217) and in the group of 40-49 years was 21.1% (68 of 322) (P = .009). In multivariable analysis, age over 45 years (adjusted odds ratio [OR], 1.941; 95% confidence interval [CI], 1.187-3.172; P = .008) and male sex (adjusted OR, 1.711; 95% CI, 1.044-2.806; P = .033) were independent risk factors for colorectal neoplasia including cancer. The prevalence of colorectal adenoma increases as the age increased in young adults under 50 years of age, especially after the age of 45 years, the risk of colorectal neoplasia increases; hence, early screening should be considered before the age of 50 years.

Young-Onset Gastrointestinal Adenocarcinoma Incidence and Survival Trends in the Northern Territory, Australia, with Emphasis on Indigenous Peoples

Background and Aims: A concerning rise in incidence of young-onset cancers globally led to the examination of trends in incidence and survival of gastrointestinal (GI) adenocarcinomas in the Northern Territory (NT), Australia, over a 28-year period, with a special emphasis on Indigenous peoples. Methods: This cross-sectional analysis of a prospective longitudinal database, NT Cancer Registry (1990−2017), includes all reported cases of GI (oesophagus, gastric, small intestinal, pancreas, colon, and rectum) adenocarcinomas. Poisson regression was used to estimate incidence ratio ratios, and survival was modelled using Cox proportional hazard models separately for people aged 18−50 years and >50 years. Results: A total of 1608 cases of GI adenocarcinoma were recorded during the time of the study. While the overall incidence in people 18−50 years remained unchanged over this time (p = 0.51), the rate in individuals aged >50 years decreased (IRR = 0.65 (95% CI 0.56−0.75; p < 0.0001)). Incidence rates were significantly less in females >50 years (IRR = 0.67 95% CI 0.59−0.75; p < 0.0001), and their survival was significantly better (HR = 0.84 (95%CI 0.72−0.98; p < 0.03)) compared to males. Overall survival across all GI subsites improved in both age cohorts, especially between 2010 and 2017 (HR = 0.45 (95%CI 0.29−0.72; p < 0.0007) and HR = 0.64 (95%CI 0.52−0.78; p < 0.0001), respectively) compared to 1990−1999, driven by an improvement in survival in colonic adenocarcinoma alone, as the survival remained unchanged in other GI subsites. The incidence was significantly lower in Indigenous patients compared to non-Indigenous patients, in both age cohorts (18−50 years IRR = 0.68 95% CI 0.51−0.91; p < 0.009 and >50 years IRR = 0.48 95% CI 0.40−0.57; p < 0.0001). However, Indigenous patients had worse survival rates (18−50 years HR = 2.06 95% CI 1.36−3.11; p < 0.0007 and >50 years HR = 1.66 95% CI 1.32−2.08; p < 0.0001). Conclusions: There is a trend towards an increased incidence of young-onset GI adenocarcinomas in the NT. Young Indigenous patients have lower incidence but worse survival across all GI subsites, highlighting significant health inequities in life expectancy. Targeted, culturally safe Indigenous community-focussed programs are needed for early detection and patient-centred management of GI adenocarcinomas.

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.

Early-Age-Onset Colorectal Cancer in Canada: Evidence, Issues and Calls to Action

The inaugural Early-Age-Onset Colorectal Cancer Symposium was convened in June 2021 to discuss the implications of rapidly rising rates of early-age-onset colorectal cancer (EAO-CRC) in Canadians under the age of 50 and the impactful outcomes associated with this disease. While the incidence of CRC is declining in people over the age of 50 in Canada and other developed countries worldwide, it is significantly rising in younger people. Canadians born after 1980 are 2 to 2.5 times more likely to be diagnosed with CRC before the age of 50 than previous generations at the same age. While the etiology of EAO-CRC is largely unknown, its characteristics differ in many key ways from CRC diagnosed in older people and warrant a specific approach to risk factor identification, early detection and treatment. Participants of the symposium offered directions for research and clinical practice, and developed actionable recommendations to address the unique needs of these individuals diagnosed with EAO-CRC. Calls for action emerging from the symposium included: increased awareness of EAO-CRC among public and primary care practitioners; promotion of early detection programs in younger populations; and the continuation of research to identify unique risk factor profiles, tumour characteristics and treatment models that can inform tailored approaches to the management of EAO-CRC.

The Role of Diet and Lifestyle in Early-Onset Colorectal Cancer: A Systematic Review

Simple Summary

This systematic review sifted through the exogenous dietary and lifestyle risk factors associated with early-onset colorectal cancer, going through the putative involvement of these exogenous risk factors in epigenetic and microbiota modifications. Given the burden of early-onset colorectal cancer and its globally increasing trend with scant literature on its pathogenesis, we believe it would be of benefit to highlight the importance of further systematic and large studies. Indeed, dietary and lifestyle modification could complement colorectal screening for early-onset colorectal cancer prevention.

Abstract

The incidence of early-onset colorectal cancer, defined as colorectal cancer occurring in young adults under the age of 50, is increasing globally. Knowledge of the etiological factors in young adults is far from complete. Questionable eoCRCs’ exogenous factors are represented by processed meat, sugary drinks, alcohol, Western dietary pattern, overweight and obesity, physical inactivity, and smoking, though with heterogeneous results. Therefore, we performed a systematic review to summarize the current evidence on the role of diet and lifestyle as eoCRC risk factors. We systematically searched PubMed, Scopus, and EMBASE up to July 2021, for original studies evaluating diet, alcohol, physical activity, BMI, and smoking in eoCRC and included twenty-six studies. Indeed, the exogenous factors could represent modifiable key factors, whose recognition could establish areas of future interventions through public health strategies for eoCRC primary prevention. Additionally, we discussed the role of additional non-modifiable risk factors, and of epigenetic regulation and microbiota as mediators of the eoCRC triggered by diet and lifestyle.

Colorectal cancer patients in a tertiary hospital in Indonesia: Prevalence of the younger population and associated factors

BACKGROUND

An increasing trend in colorectal cancer (CRC) occurring at younger ages has been observed worldwide, even though incidence is declining in the general population. Most currently available guidelines still recommend CRC screening for older populations, despite an alarming rise in early-onset CRC incidence. Risk stratification is necessary to further determine the population most at risk for early-onset CRC. However, epidemiological data on related clinical characteristics and potential risk factors, especially in developing countries, have not been widely reported.

AIM

To investigate the prevalence, demographics, clinicopathologic features, and associated factors of young-onset CRC patients in a tertiary hospital in Indonesia.

METHODS

Patients undergoing colonoscopy examination between 2008 and 2019, yielding a diagnosis of CRC were identified from medical records. The subjects were classified into two groups according to their age at diagnosis, namely early-onset (18-49 years old) and late-onset (≥ 50-years-old). Demographic data, characteristics, and risk factors of both onset age groups were evaluated using the chi-square and Fisher’s exact test.

RESULTS

Among 495 CRC patients confirmed by histopathology, 205 (41.4%) were classified as early-onset and 290 (58.6%) as late-onset. Most subjects in the early-onset CRC group were male (53.7%), with 89.8% displaying adenocarcinoma histopathology. A majority (78%) of the early-onset CRC patients had left-sided tumors, with the rectum (41%) and rectosigmoid (17.6%) being the most common sites. Abdominal pain was the most frequent symptom in the early-onset CRC patients (55.6%), which was significantly higher than that in the late-onset CRC patients (43.8%, P < 0.05). Early-onset CRC cases were more likely to be underweight (34.6% vs 20.0%, P < 0.001) compared to late-onset CRC cases. The proportion of subjects with suspected hereditary nonpolyposis colorectal cancer (HNPCC) was also higher in the early-onset CRC group than in the late-onset age group (9.3% vs 4.1%, P < 0.05). However, no difference was observed in the parental or family histories of CRC cases.

CONCLUSION

Early-onset CRC patients were more likely to have abdominal pain, underweight status, and HNPCC suspicion than late-onset CRC patients.

Association of Body Mass Index With Risk of Early-Onset Colorectal Cancer: Systematic Review and Meta-Analysis

INTRODUCTION

Incidence of colorectal cancer (CRC) in young adults has been increasing in recent decades in many countries for still widely unclear reasons. Suspected candidates include increasing prevalence of overweight and obesity, but specific evidence on their role for early-onset CRC (EOCRC) is sparse. We conducted a systematic review and meta-analysis to summarize available evidence on the association of body mass index (BMI) with EOCRC.

METHODS

We systematically searched PubMed, EMBASE, and Web of Science up to February 2021 for studies that evaluated the association of BMI (before diagnosis but not near diagnosis) with CRC risk and reported specific results for EOCRC. Results from studies with similar BMI groupings were summarized in meta-analyses using random-effects models.

RESULTS

Twelve studies were eligible and included. Results of 6 studies were pooled in meta-analyses, which yielded a higher risk of EOCRC for overweight and obesity (BMI ≥25 kg/m2) compared with normal weight (odds ratio [OR] 1.42, 95% confidence interval [CI] 1.19-1.68). An increasing risk with increasing BMI was observed, with much higher risk for obesity (OR 1.88, 95% CI 1.40-2.54) than for overweight (OR 1.32, 95% CI 1.19-1.47).

DISCUSSION

Obesity is a strong risk factor for EOCRC, and its increasing prevalence in younger generations is likely to substantially contribute to the increase in EOCRC. Efforts to limit the obesity epidemic in adolescents and younger adults may be crucial for reducing CRC incidence in future generations of adults.

Risk Factors Associated With Early-Onset Colorectal Neoplasm in Chinese Youth: A Prospective Population-Based Study

Evidence of the risk factors associated with early-onset colorectal neoplasm from prospective population-based studies is limited. We enrolled 17,293 participants younger than 50 years from the Shanghai colorectal cancer (CRC) screening program cohort. Face-to-face interviews were performed by trained primary care physicians using a standardized questionnaire to collect the information on potential risk factors at baseline entry. Furthermore, 124 cases of early-onset colorectal neoplasm, including six CRC cases and 118 colorectal adenoma (CRA) cases, were detected between 2012 and 2016. Multivariable logistic regression models and restricted cubic spline (RCS) were used to evaluate the risk factors associated with early-onset colorectal neoplasm. We found that sex, body mass index (BMI), and family history of CRC were associated with the early onset of colorectal neoplasm. The RCS model showed a positive dose–response and linear association between BMI and risk of early-onset colorectal neoplasm among young participants (p-overall = 0.19, p-nonlinear = 0.97). The findings indicated that it was beneficial for normal people younger than 50 years to start opportunistic CRC screening. As for those at high risk, increased surveillance is strongly recommended. Further close follow-up is required for research on the underlying causes of early-onset CRC.

Colorectal Cancer, Age, and Obesity-Related Comorbidities: A Large Database Study

BACKGROUND AND AIMS

The association between obesity and colorectal cancer (CRC) is well established in older individuals, but evidence is limited in the younger population. The study aims to analyze the relationship of obesity and its related comorbidities in early-onset CRC (E-CRC) and compare it to late-onset CRC (L-CRC).

METHODS

A retrospective, cross-sectional study was performed on average-risk individuals ≥ 20 years who were active patients in the commercial database, IBM Watson Health Explorys in the last 5 years. Individuals with CRC were compared to those without CRC across different age groups (20-39, 40-49, and 50-74 years). Individuals with CRC diagnosed < 50 years (E-CRC) were compared to those with CRC between 50 and 74 years (L-CRC). Variables included sex, smoking, obese BMI, diabetes mellitus type 2 (DM2), hypertension (HTN), and hyperlipidemia (HLD). Since Explorys aggregates population-level, de-identified data, approval from institutional review board was not required.

RESULTS

Among 37,483,140 individuals, 162,150 cases of sporadic CRC were identified. Compared to the general population, obesity and HLD were independent risk factors for CRC across all age groups; DM2, HTN, and smoking were independent risk factors for CRC in men of all age groups and women with L-CRC. Compared to L-CRC, individuals with E-CRC had lower percentages of obesity-related comorbidities.

CONCLUSION

In E-CRC, obesity, DM2, HTN, HLD, and smoking are independent risk factors for CRC among men; obesity and HLD are independent risk factors for CRC in women. These subgroups may benefit from a personalized screening approach to detect early-onset CRC.

Risk factors for early-onset colorectal cancer: a population-based case-control study in Ontario, Canada

Purpose

There has been an alarming increase in colorectal cancer (CRC) incidence among young adults aged < 50 years, and factors driving this upward trend are unknown. This study investigated associations between various medical, lifestyle, and dietary factors and risk of early-onset CRC (EO-CRC).

Methods

A population-based case–control study was conducted in Ontario, Canada during 2018–2019. EO-CRC cases aged 20–49 years (n = 175) were identified from the Ontario Cancer Registry; sex- and age group-matched controls (n = 253) were recruited through random digit dialing. Data on potential a priori risk factors were collected using a web-based self-reported questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using multivariable logistic regression.

Results

Family history of CRC in a first- or second-degree relative (OR 2.37; 95% CI 1.47–3.84), longer sedentary time (≥ 10 vs. < 5 h/day, OR 1.93; 95% CI 1.02–3.65), greater consumption of sugary drinks (≥ 7 vs. < 1 drinks/week, OR 2.99; 95% CI 1.57–5.68), and a more Westernized dietary pattern (quartile 4 vs. 1, OR 1.92; 95% CI 1.01–3.66) were each associated with an increased risk of EO-CRC. Conversely, calcium supplement use (OR 0.53; 95% CI 0.31–0.92), history of allergy or asthma (OR 0.62; 95% CI 0.39–0.98), and greater parity in females (≥ 3 vs. nulliparity, OR 0.29; 95% CI 0.11–0.76) were each associated with a reduced risk.

Conclusion

Modifiable factors, particularly sedentary behavior and unhealthy diet including sugary drink consumption, may be associated with EO-CRC risk. Our findings, if replicated, may help inform prevention strategies targeted at younger persons.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10552-021-01456-8.

Nongenetic Determinants of Risk for Early-Onset Colorectal Cancer

Background

Incidence of early-onset (younger than 50 years of age) colorectal cancer (CRC) is increasing in many countries. Thus, elucidating the role of traditional CRC risk factors in early-onset CRC is a high priority. We sought to determine whether risk factors associated with late-onset CRC were also linked to early-onset CRC and whether association patterns differed by anatomic subsite.

Methods

Using data pooled from 13 population-based studies, we studied 3767 CRC cases and 4049 controls aged younger than 50 years and 23 437 CRC cases and 35 311 controls aged 50 years and older. Using multivariable and multinomial logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) to assess the association between risk factors and early-onset CRC and by anatomic subsite.

Results

Early-onset CRC was associated with not regularly using nonsteroidal anti-inflammatory drugs (OR = 1.43, 95% CI = 1.21 to 1.68), greater red meat intake (OR = 1.10, 95% CI = 1.04 to 1.16), lower educational attainment (OR = 1.10, 95% CI = 1.04 to 1.16), alcohol abstinence (OR = 1.23, 95% CI = 1.08 to 1.39), and heavier alcohol use (OR = 1.25, 95% CI = 1.04 to 1.50). No factors exhibited a greater excess in early-onset compared with late-onset CRC. Evaluating risks by anatomic subsite, we found that lower total fiber intake was linked more strongly to rectal (OR = 1.30, 95% CI = 1.14 to 1.48) than colon cancer (OR = 1.14, 95% CI = 1.02 to 1.27; P = .04).

Conclusion

In this large study, we identified several nongenetic risk factors associated with early-onset CRC, providing a basis for targeted identification of those most at risk, which is imperative in mitigating the rising burden of this disease.

Rising incidence of early-onset colorectal cancer - a call to action

The incidence of early-onset colorectal cancer (CRC), which occurs in individuals <50 years of age, has been increasing worldwide and particularly in high-income countries. The reasons for this increase remain unknown but plausible hypotheses include greater exposure to potential risk factors, such as a Western-style diet, obesity, physical inactivity and antibiotic use, especially during the early prenatal to adolescent periods of life. These exposures can not only cause genetic and epigenetic alterations in colorectal epithelial cells but also affect the gut microbiota and host immunity. Early-onset CRCs have differential clinical, pathological and molecular features compared with later-onset CRCs. Certain existing resources can be utilized to elucidate the aetiology of early-onset CRC and inform the development of effective prevention, early detection and therapeutic strategies; however, additional life-course cohort studies spanning childhood and young adulthood, integrated with prospective biospecimen collections, omics biomarker analyses and a molecular pathological epidemiology approach, are needed to better understand and manage this disease entity. In this Perspective, we summarize our current understanding of early-onset CRC and discuss how we should strategize future research to improve its prevention and clinical management.

An Update on the Epidemiology, Molecular Characterization, Diagnosis, and Screening Strategies for Early-Onset Colorectal Cancer

Rising trends in the incidence and mortality of early-onset colorectal cancer (CRC) in those who are younger than 50 years have been well established. These trends have spurred intense investigation focused on elucidating the epidemiology and characteristics of early-onset CRC, as well as on identifying strategies for early detection and prevention. In this review, we provide a contemporary update on early-onset CRC with a particular focus on epidemiology, molecular characterization, red flag signs and symptoms, and screening for early-onset CRC.

Comparison of Risk of Metachronous Advanced Colorectal Neoplasia in Patients with Sporadic Adenomas Aged < 50 Versus ≥ 50 years: A Systematic Review and Meta-Analysis

No specific recommendations are available for the surveillance of young patients aged <50 years undergoing polypectomy. We aimed to compare the risk of metachronous advanced colorectal neoplasia (ACRN) between patients aged ≥50 years and those aged <50 years who underwent polypectomy. Studies published between January 1980 and June 2020 that examined the risk of metachronous ACRN were searched. We performed a meta-analysis for the metachronous ACRN risk in patients with sporadic colorectal adenomas according to the age groups (≥50 vs. <50 years). Eight individual studies were included in the meta-analysis. The risk of metachronous ACRN was higher in patients aged ≥50 years than in those aged <50 years without significant heterogeneity (odds ratio (OR) (95% CI): 1.62 (1.34–1.96), I² = 14%). The impact of the age group on the risk of metachronous ACRN was identified in both the low-risk (LRA) and high-risk (HRA) adenoma groups (≥50 vs. <50 years: LRA, OR 1.88 (95% CI 1.30–2.70); HRA, OR 1.50 [95% CI 1.13–2.00]). In conclusion, patients aged <50 years had a lower risk of metachronous ACRN than older patients. Young patients with sporadic adenomas do not require more intensive surveillance; rather, the surveillance interval may be extended in these patients.

Risk Factors for Early-Onset Colorectal Cancer

BACKGROUND & AIMS

Colorectal cancer (CRC) incidence and mortality are increasing among persons younger than 50 years old in the United States, but risk factors associated with early-onset CRC (EOCRC) have not been widely studied.

METHODS

We conducted a case-control study of US veterans 18 to 49 years old who underwent colonoscopy examinations from 1999 through 2014. EOCRC cases were identified from a national cancer registry; veterans who were free of CRC at their baseline colonoscopy through 3 years of follow-up were identified as controls. We collected data on age, sex, race/ethnicity, body weight, body mass index (BMI), diabetes, smoking status, and aspirin use. Multivariate-adjusted EOCRC odds were estimated for each factor, with corresponding 95% confidence interval (CI) values.

RESULTS

Our final analysis included 651 EOCRC cases and 67,416 controls. Median age was 45.3 years, and 82.3% were male. Higher proportions of cases were older, male, current smokers, nonaspirin users, and had lower BMIs, compared with controls (P < .05). In adjusted analyses, increasing age and male sex were significantly associated with increased risk of EOCRC, whereas aspirin use and being overweight or obese (relative to normal BMI) were significantly associated with decreased odds of EOCRC. In post hoc analyses, weight loss of 5 kg or more within the 5-year period preceding colonoscopy was associated with higher odds of EOCRC (odds ratio 2.23; 95% CI 1.76-2.83).

CONCLUSIONS

In a case-control study of veterans, we found increasing age and male sex to be significantly associated with increased risk of EOCRC, and aspirin use to be significantly associated with decreased risk; these factors also affect risk for CRC onset after age 50. Weight loss may be an early clinical sign of EOCRC. More intense efforts are required to identify the factors that cause EOCRC and signs that can be used to identify individuals at highest risk.

Sporadic colorectal cancer in adolescents and young adults: a scoping review of a growing healthcare concern

PURPOSE

Sporadic colorectal cancer (CRC) amongst adolescents and young adults (AYA) is increasing in incidence. The reasons for this trend are not well understood. Current guidelines do not specifically address this patient cohort. A scoping review was performed to summarise the range of available evidence and identify key areas that need to be addressed in current guidelines.

METHODS

A systematic literature search was conducted adhering to the PRISMA statement. All potentially eligible studies were screened, and data extraction was performed by two reviewers independently. The studies were then divided into 5 broad subgroups: (1) risk factors, (2) screening, (3) clinicopathological and molecular features, (4) presentation and (5) management. Descriptive statistics were used for data analysis.

RESULTS

A total of 17 studies were included from 2010 to 2019. Overall, young adults with CRC tend to present with non-specific symptoms. The majority of these patients have a delayed diagnosis and more advanced disease at presentation, with a rise in prevalence of distal colon and rectal cancers. AYAs tend to have poorly differentiated tumours and are managed more aggressively. Overall 5-year survival varies between studies.

CONCLUSION

This is, to our knowledge, the first scoping review presenting the range of available evidence on CRC in AYAs. Although the rise in incidence is recognised by specialist bodies, recommendations are limited by the sparsity of available data. We seek to highlight the need for further research, define the role of earlier screening and raise awareness to promote thorough assessment of young patients.

Colorectal cancer risk based on extended family history and body mass index

Family history and body mass index (BMI) are well-known risk factors for colorectal cancer (CRC), however, their joint effects are not well described. Using linked data for genealogy, self-reported height and weight from driver's licenses, and the Utah Surveillance, Epidemiology, and End-Results cancer registry, we found that an increasing number of first-degree relatives (FDR) with CRC is associated with higher standardized incidence ratio (SIR) for overweight/obese probands but not for under/normal weight probands. For probands with two CRC-affected FDRs, the SIR = 1.91 (95% CI [0.52, 4.89]) for under/normal weight probands and SIR = 4.31 (95% CI [2.46, 7.00]) for overweight/obese probands. In the absence of CRC-affected FDRs, any number of CRC-affected SDRs did not significantly increase CRC risk for under/normal weight probands, but for overweight/obese probands with at least three CRC-affected SDRs the SIR = 2.68 (95% CI [1.29, 4.93]). In the absence of CRC-affected FDRs and SDRs, any number of CRC-affected third-degree relatives (TDRs) did not increase risk in under/normal weight probands, but significantly elevated risk for overweight/obese probands with at least two CRC-affected TDRs was observed; SIR = 1.32 (95% CI [1.04, 1.65]). For nonsyndromic CRC, maximum midlife BMI affects risk based on family history and should be taken into account for CRC risk communication when possible.

Symptoms and demographic factors associated with early-onset colorectal neoplasia among individuals undergoing diagnostic colonoscopy

BACKGROUND

The incidence and mortality of colorectal cancer (CRC) are increasing in adults under 50 years. Risk factors associated with early-onset colorectal neoplasia (CRN) are uncertain. We aimed to identify clinical predictors associated with the presence of CRN detected by diagnostic colonoscopy in symptomatic individuals under 50 years of age.

METHODS

We used a single-center endoscopy database to identify symptomatic patients 18-49 years of age who underwent ambulatory colonoscopy between 2007 and 2017. Pathology reports identified CRN as adenomas, advanced adenomas (based on size or histology), or adenocarcinomas. Multivariable analysis was used to determine factors associated with CRN.

RESULTS

We identified 4333 eligible patients of whom 363 (8.4%) had any CRN and 48 (1.1%) had advanced neoplasia (advanced adenoma or adenocarcinoma). Factors associated with any CRN on multivariable analysis included male sex [odds ratio (OR) 1.50 (1.19-1.88)], older age group [compared to 18-29 years, OR for 30-39: 3.12 (1.93-5.04); OR for 40-49: 4.68 (2.97-7.36)], obesity [OR for BMI 30-34.9 compared to 18-24.9: 1.44 (1.04-2.01)], and any tobacco use [OR 1.63 (1.18-2.23)]. Anemia was associated with advanced neoplasia [OR 3.11 (1.32-7.34)]. Of the advanced neoplastic lesions, 38 of 48 (79.2%) were located in the distal colon.

CONCLUSIONS

In the largest study to date of symptomatic individuals under 50 years of age undergoing colonoscopy in the USA, advanced CRN was most often detected in the distal colon and was associated with anemia, but not with abnormal bowel habits or abdominal pain. We also found that patients with CRN under 50 years of age were more likely to be male, smokers, and obese. These findings should prompt further investigation of these risk factors alone and in combination.

Risk Factors Associated With Young-Onset Colorectal Adenomas and Cancer: A Systematic Review and Meta-Analysis of Observational Research

The risk of young-onset colorectal adenomas and cancer (yCRAC) in adults less than 50 years of age is increasing. We conducted a systematic review and meta-analysis of epidemiologic studies to identify lifestyle and clinical risk factors associated with yCRAC risk. We searched Medline, EMBASE, and Cochrane Database of Systematic Reviews for studies which: used an epidemiologic study design, involved individuals with yCRAC, evaluated at least 1 lifestyle or clinical factor, and applied multivariable regression approaches. We critically appraised the quality of included studies and calculated pooled measures of association (e.g. odds ratio [OR]) and 95% confidence intervals (CI) using random-effects models. We identified 499 articles in our search with 9 included in a narrative synthesis and 6 included in a meta-analysis. We found in the pooled analysis that smoking and alcohol consumption were lifestyle factors associated with yCRAC, as were clinical factors including obesity elevated blood glucose, elevated blood pressure, and elevated triglycerides. We identified lifestyle and clinical risk factors associated with risk of yCRAC, which have potential implications for informing preventive efforts and modifying screening to target at-risk populations.

Colorectal Cancer in the Adolescent and Young Adult Population

Colorectal cancer in the young adult population is of increasing incidence and concern. Genetic predisposition and heritable syndromes contribute to this trend, but perhaps more concerning is the majority of new diagnoses that involve no traceable genetic risk factors. Prevention and early recognition, with a high suspicion in the symptomatic young adult, are critical in attenuating recent trends. Clinical management requires coordinated multidisciplinary care from diagnosis to surveillance in order to ensure appropriate management. This review provides a summary of key aspects related to colorectal cancer in adolescents and young adults, including epidemiology, biology, genetics, clinical management, and prevention.