High frequency of KRAS mutation in early onset colorectal adenocarcinoma: implications for pathogenesis. Hum Pathol. 2016;56:163-170. [PMID: 27346571 DOI: 10.1016/j.humpath.2016.06.010]

Investigating the WNT and TGF-beta pathways alterations and tumor mutant burden in young-onset colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the United States. Recent epidemiological evidence demonstrates an increasing incidence of young-onset CRC cases, defined as CRC cases in individuals 50 years old or younger. Studies have established that alterations in both the WNT and TGF-Beta signaling pathways have contributed to CRC development. While this is well understood, the comprehensive analysis of WNT and TGF-Beta pathway alterations in young-onset CRC cases has yet to be investigated. Here, we conducted a comprehensive bioinformatics analysis of mutations associated with each of the WNT and TGF-Beta signaling pathways according to age (≤ 50 years old versus > 50 years old) utilizing published genomic data from the cBioPortal. Chi-square results demonstrated no significant difference in WNT alterations between young-onset CRC and those > 50 years old. However, across all age groups, WNT alterations were frequently found in rectal cancers. We also found that WNT alterations were associated with better outcomes. The mutations associated with TGF-beta were observed at a higher rate in older CRC patients when compared to those ≤ 50 years old. Additionally, these mutations were found more frequently in colon primaries.

Comparative characteristics of early-onset vs. late-onset advanced colorectal cancer: a nationwide study in China

BACKGROUND

The incidence of early-onset colorectal cancer (EOCRC, diagnosed in patients under the age of 50 years) has been increasing around the world. Here, we aimed to systematically identify distinctive features of EOCRC.

METHODS

From 2020 to 2021, we conducted a nationwide survey in 19 hospitals, collecting data on advanced CRC patients' demographics, clinical features, disease knowledge, medical experiences, expenditures, and health-related quality of life (HRQOL). We compared these features between EOCRC and late-onset colorectal cancer (LOCRC, ≥ 50 years old) groups and analyzed the association between EOCRC and HRQOL using multivariate linear regression.

FINDINGS

In total, 991 patients with EOCRC and 3581 patients with LOCRC were included. Compared to the LOCRC group, the EOCRC group had higher levels of education, were more informed about the risk factors for CRC, were more likely to have widespread metastases throughout the body, were more inclined to undergo gene testing, and were more likely to opt for targeted therapy, radiotherapy, and chemotherapy. However, HRQOL in the EOCRC group was similar to that of the LOCRC group, and no significant association was observed between EOCRC and HRQOL (beta: -0.753, P value: 0.307).

INTERPRETATION

In Chinese patients, EOCRC patients had more aggressive features. Despite undergoing more intensified treatments and gene testing, they had similar HRQOL compared with LOCRC. These findings advocate for a more tailored approach to treatment, especially for young CRC patients with advanced TNM stages and metastasis.

Differential landscape of immune evasion in oncogenic RAS-driven primary and metastatic colorectal cancers

Oncogenic drivers such as KRAS extensively modulate the tumor inflammatory microenvironment (TIME) of colorectal cancer (CRC). The influence of KRAS on modulating immune cell composition remains unclear. The objective of this study was to identify signatures of infiltrative immune cells and distinctive patterns that differ between RAS wild-type (WT) and oncogenic mutant (MT) CRC that explain immune evasion in MT tumors. A total of 7,801 CRC specimens were analyzed using next-generation DNA sequencing, whole-exome sequencing, and/or whole transcriptome sequencing. Deficiency of mismatch repair (dMMR)/microsatellite instability (MSI) and tumor mutation burden (TMB) were also assessed. KRAS mutations were present in 48% of CRC, similarly distributed in patients younger than vs. 50 years and older. In microsatellite stable (MSS) KRAS MT tumors, composition of the TIME included higher neutrophil infiltration and lower infiltration of B cells. MSI-H/dMMR was significantly more prevalent in RAS WT (9.1%) than in KRAS MT (2.9%) CRC. In MSS CRC, TMB-high cases were significantly higher in RAS MT (3.1%) than in RAS WT (2.1%) tumors. KRAS and NRAS mutations are associated with increased neutrophil infiltration, with codon-specific differences. These results demonstrate significant differences in the TIME of RAS mutant CRC that match previous reports of immunoevasive characteristics of such tumors.

Focusing on colorectal cancer in young adults (Review)

Colorectal cancer (CRC) ranks as the third leading cause of cancer-related mortality worldwide. Recent years have witnessed an increase in the incidence of CRC among adults <50 years old on a global scale. The increased incidence is associated with several modifiable risk factors, including obesity, type II diabetes, physical inactivity and frequent antibiotic use. In younger individuals, haematochezia and abdominal pain are the most common symptoms, predominantly affecting the left-side colon. While certain cases of early-onset CRC (eoCRC) are associated with a genetic predisposition, the majority result from sporadic mutations in the genes APC, KRAS, BRAF and TP53, which trigger uncontrolled cell proliferation and tumour formation. Colorectal carcinogenesis involves three major pathways: The chromosomal instability (CIN), microsatellite instability and CpG island methylator phenotype pathways. Dysregulation of the CIN pathway accounts for 85% of sporadic cases of eoCRC. Notably, eoCRC exhibits a distinctive molecular profile, characterized by a decreased prevalence of BRAF mutations, an increased prevalence of KRAS mutations and LINE-1 hypomethylation, and involvement of the Microsatellite and Chromosomal Stable pathway. Prevention strategies for eoCRC primarily centre on lifestyle modifications and the development of screening programs targeting younger populations. Further exploration into the molecular mechanisms involved in the identification of novel risk factors associated with eoCRC is imperative. These efforts, in conjunction with the development of specific screening strategies, hold the potential to reduce morbidity and mortality in the future.

KRAS Sequence Variation as Prognostic Marker in Patients With Young- vs Late-Onset Colorectal Cancer

Importance

The understanding of the association between KRAS sequence variation status and clinical outcomes in colorectal cancer (CRC) has evolved over time.

Objective

To characterize the association of age at onset, tumor sidedness, and KRAS sequence variation with survival among patients diagnosed with CRC.

Design, Setting, and Participants

This cross-sectional study used data extracted from the Surveillance, Epidemiology, and End Results database. Patients diagnosed with adenocarcinoma of the colon or rectum from 2010 through 2015 were included and were classified as having young-onset (YO) cancer if diagnosed between ages 20 to 49 years and late-onset (LO) cancer if diagnosed at age 50 years or older. Data were analyzed from April 2021 through August 2023.

Main Outcomes and Measures

CRC cause-specific survival (CSS) was summarized using Fine and Gray cumulative incidence and Kaplan-Meier curves. Estimation of subdistribution hazard ratios (sHRs) for the association of KRAS status, age at onset, and tumor location with CRC CSS was conducted using the Fine and Gray competing risk model. Cox proportional hazards regression was used to estimate and compare HRs.

Results

Among 21 661 patients with KRAS sequence variation status (mean [SD] age at diagnosis, 62.50 [13.78] years; 9784 females [45.2%]), 3842 patients had YO CRC, including 1546 patients with KRAS variants, and 17 819 patients had LO CRC, including 7311 patients with KRAS variants. There was a significant difference in median CSS time between patients with variant vs wild-type KRAS (YO: 3.0 years [95% CI, 2.8-3.3 years] vs 3.5 years [95% CI, 3.3-3.9 years]; P = .02; LO: 2.5 years [95% CI, 2.4-2.7 years] vs 3.4 years [95% CI, 3.3-3.6 years]; P < .001). Tumors with variant compared with wild-type KRAS were associated with higher risk of CRC-related death (YO: sHR, 1.09 [95% CI, 1.01-1.18]; P = .03; LO: sHR, 1.06 [95% CI, 1.02-1.09]; P = .002). Among patients with YO cancer, mortality hazards increased by location, from right (sHR, 1.02 [95% CI, 0.88-1.17) to left (sHR, 1.15 [95% CI, 1.02-1.29) and rectum (sHR, 1.16 [95% CI, 0.99-1.36), but no trend by tumor location was seen for LO cancer.

Conclusions and Relevance

In this study of patients diagnosed with CRC, KRAS sequence variation was associated with increased mortality among patients with YO and LO tumors. In YO cancer, variant KRAS-associated mortality risk was higher in distal tumors than proximal tumors.

Biological and clinical implications of early-onset cancers: A unique subtype

In recent years, the incidence of cancers is continuously increasing in young adults. Early-onset cancer (EOC) is usually defined as patients with cancers under the age of 50, and may represent a unique subgroup due to its special disease features. Overall, EOCs often initiate at a young age, present as a better physical performance but high degree of malignancy. EOCs also share common epidemiological and hereditary risk factors. In this review, we discuss several representative EOCs which were well studied previously. By revealing their clinical and molecular similarities and differences, we consider the group of EOCs as a unique subtype compared to ordinary cancers. In consideration of EOC as a rising threat to human health, more researches on molecular mechanisms, and large-scale, prospective clinical trials should be carried out to further translate into improved outcomes.

Log odds of positive lymph nodes show better predictive performance on the prognosis of early-onset colorectal cancer

BACKGROUND

As the incidence of colorectal cancer tends to be younger, early-onset colorectal cancer (EOCRC) has attracted more attention in recent years. We aimed to assess the optimal lymph node staging system among EOCRC patients, and then, establish informative assessment models for prognosis prediction.

METHODS

Data of EOCRC were retrieved from the Surveillance, Epidemiology, and End Results database. Survival prediction ability of three lymph node staging systems including N stage of the tumor node metastasis (TNM) staging system, lymph node ratio (LNR), and log odds of positive lymph nodes (LODDS) was assessed and compared using Akaike information criterion (AIC), Harrell's concordance index (C-index), and likelihood ratio (LR) test. Univariate and multivariate Cox regression analyses were conducted to identify the prognostic predictors for overall survival (OS) and cancer-specific survival (CSS). Effectiveness of the model was demonstrated by receiver operative curve and decision curve analysis.

RESULTS

A total of 17,535 cases were finally included in this study. All three lymph node staging systems showed significant performance in survival prediction (p < 0.001). Comparatively, LODDS presented a better ability of prognosis prediction with lower AIC (OS: 70,510.99; CSS: 60,925.34), higher C-index (OS: 0.6617; CSS: 0.6799), and higher LR test score (OS: 998.65; CSS: 1103.09). Based on independent factors identified from Cox regression analysis, OS and CSS nomograms for EOCRC were established and validated.

CONCLUSIONS

LODDS shows better predictive performance than N stage or LNR among patients with EOCRC. Novel validated nomograms based on LODDS could effectively provide more prognostic information than the TNM staging system.

Analysis of Circulating Tumor DNA in Synchronous Metastatic Colorectal Cancer at Diagnosis Predicts Overall Patient Survival

Sporadic colorectal cancer (sCRC) initially presents as metastatic tumors in 25-30% of patients. The 5-year overall survival (OS) in patients with metastatic sCRC is 50%, falling to 10% in patients presenting with synchronous metastatic disease (stage IV). In this study, we systematically analyzed the mutations of RAS, PIK3CA and BRAF genes in circulating tumor DNA (ctDNA) and tumoral tissue DNA (ttDNA) from 51 synchronous metastatic colorectal carcinoma (SMCC) patients by real-time PCR, and their relationship with the clinical, biological and histological features of disease at diagnosis. The highest frequency of mutations detected was in the KRAS gene, in tumor biopsies and plasma samples, followed by mutations of the PIK3CA, NRAS and BRAF genes. Overall, plasma systematically contained those genetic abnormalities observed in the tumor biopsy sample from the same subject, the largest discrepancies detected between the tumor biopsy and plasma from the same patient being for mutations in the KRAS and PIK3CA genes, with concordances of genotyping results between ttDNA and ctDNA at diagnosis of 75% and 84%, respectively. Of the 51 SMCC patients in the study, 25 (49%) showed mutations in at least 1 of the 4 genes analyzed in patient plasma. From the prognostic point of view, the presence and number of the most common mutations in the RAS, PIK3CA and BRAF genes in plasma from SMCC patients are independent prognostic factors for OS. Determination of the mutational status of ctDNA in SMCC could be a key tool for the clinical management of patients.

Distinct Molecular Profiles of Sporadic Early-Onset Colorectal Cancer: A Population-Based Cohort and Systematic Review

Background and Aims

The observed increase in the incidence of early-onset colorectal cancer (EOCRC) is being driven by sporadic cases, but the molecular characteristics of these tumors are not fully understood. Our objective was to investigate the prevalence of microsatellite instability (MSI) and selected mutations in sporadic EOCRC, and their association with survival.

Methods

Firstly, we compared the prevalence of molecular characteristics and survival within a population-based cohort study of 652 stage II and III colon cancer patients in Northern Ireland, comparing sporadic early-onset (<50 years, n = 35) with older (60-69 years, n = 179) patients. Secondly, a systematic review for studies reporting the prevalence of MSI, mismatch repair deficiency (dMMR), or BRAF, KRAS, NRAS, PIK3CA, and TP53 mutations in sporadic EOCRC was conducted. A meta-analysis was performed to calculate pooled estimates of the prevalence of molecular features in sporadic EOCRC.

Results

Firstly, within the cohort study, EOCRC patients did not have a significantly increased risk of colorectal cancer-specific death (adjusted hazard ratio 1.20; 95% confidence interval [CI] 0.61-2.39) compared with 60- to 69-year-olds. Second, 32 studies were included in the systematic review. The pooled analysis estimated a prevalence of 10% (95% CI 7%-14%) for MSI high/dMMR in sporadic EOCRC. BRAF and KRAS mutations had a prevalence of 1% (95% CI 0%-3%) and 32% (95% CI 23%-40%), respectively.

Conclusion

The molecular characteristics of sporadic EOCRC differ from those of cancers in older adults, particularly regarding reduced prevalence of BRAF mutations. Ten percent of sporadic EOCRC display MSI high/dMMR. Further studies are needed to address survival in sporadic EOCRC cases and whether molecular profiles influence EOCRC outcomes in this patient group.

Trends, clinicopathological features, surgical treatment patterns and prognoses of early-onset versus late-onset colorectal cancer: A retrospective cohort study on 34067 patients managed from 2000 to 2021 in a Chinese tertiary center

BACKGROUND

In recent decades, the incidence of early-onset colorectal cancer (EOCRC) has reportedly increased in several developed countries, whereas that of late-onset colorectal cancer (LOCRC) has decreased continuously. The trends, clinicopathological features, surgical treatment patterns, and prognoses of EOCRC and LOCRC in China remain unclear.

MATERIALS AND METHODS

This retrospective cohort study was performed in China using data from our pathology registry collected in 2000-2021. Pathologically confirmed cases of colorectal cancer (CRC) were analyzed. The average annual percentage change (AAPC) was estimated to quantify the secular trends. Clinicopathological features, surgical treatment patterns, and prognoses were compared between the two groups. Multivariate Cox regression analyses were performed for disease-free survival and overall survival.

RESULTS

A total of 34,067 cases of CRC were included, with 6,369 cases of EOCRC and 27,698 cases of LOCRC. Overall, the numbers of EOCRC (AAPC = 8.4%), LOCRC (AAPC = 11.6%), and CRC (AAPC = 11.0%) cases increased significantly from 2000 to 2021. Compared to the LOCRC group, the EOCRC group had fewer men, comorbidities, concomitant cancers, polyps, and KRAS mutations; more symptoms, rectal cancers, multiple primary CRCs, deficient mismatch repair tumors, poorly differentiated, mucinous adenocarcinoma or signet ring cell carcinoma, advanced TNM stage, vascular invasion, perineural invasion; less laparoscopic surgery and sphincter-preserving surgery; more extended radical resection, perioperative chemoradiotherapy and targeted therapy; and similar disease-free and overall survival rates.

CONCLUSION

The numbers of EOCRC and LOCRC cases have continuously increased over the last two decades. The EOCRC group has more aggressive features, advanced TNM stage, intensified surgical treatment and perioperative treatment than the LOCRC group, but similar disease-free and overall survival rates. More CRC screening programs are recommended for younger adults to combat the rapidly increasing trend of EOCRC.

Nomogram predicting the cancer-specific survival of early-onset colorectal cancer patients with synchronous liver metastasis: a population-based study

PURPOSE

This research aimed to explore prognostic factors for early-onset colorectal cancer (EO-CRC) patients with liver metastasis (LM) and develop nomogram for predicting cancer-specific survival (CSS) probability quantitatively.

METHODS

Our study included 4368 EO-CRC patients with LM registered in the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2017. Potential prognostic factors for EO-CRC patients with LM were identified by multivariable Cox regression analysis. Prognostic nomogram was subsequently constructed based on these prognostic factors. The discriminative ability, calibration, and clinical usefulness of the nomogram were assessed by the area under the receiver operating characteristic (ROC) curves (AUC), calibration curves, and decision curve analysis (DCA).

RESULTS

In the training cohort, marital status, primary tumor location, histopathological grade, T stage, number of metastatic organs, carcinoembryonic antigen (CEA), perineural invasion (PI), surgery of primary site, chemotherapy, radiation therapy, and metastatic lymph nodes ratio (LNR) were prognostic factors for cancer-specific mortality of EO-CRC patients with LM. The 1-, 2-, and 3-year AUC values of the prognostic nomogram were 0.777, 0.781, and 0.788, respectively. Calibration curves indicated acceptable agreement between nomogram-predicted survival and actual observed survival at 1, 2, and 3 years. DCA curves exhibited good positive net benefits in the prognostic model in most threshold probabilities at different time points. All of these results were reproducible in the validation cohort.

CONCLUSIONS

This study identified prognostic factors for EO-CRC patients with LM and developed a prognostic nomogram with good performance and clinical usability, which may help clinicians make better treatment decisions.

Clinical and molecular profile of young adults with early-onset colorectal cancer: Experience from four Australian tertiary centers

BACKGROUND

Patients with early-onset colorectal cancer (EO-CRC) have unique characteristics. Contemporary data on the pathological and molecular features, and survival of EO-CRC are limited in the Australian context.

AIM

To determine the demographic, histopathological and molecular characteristics of adults with EO-CRC, and their survival.

METHODS

We conducted a retrospective study of adults aged 18-49 years with EO-CRC who were referred to the Illawarra Shoalhaven Local Health District, South Eastern Sydney Local Health District and Royal North Shore Hospital in New South Wales, Australia, between 2014 and 2018.

RESULTS

Of 257 patients included, 94 (37%) patients presented with de novo metastatic CRC, 80% patients had near-average risk family history and 89% had a symptomatic presentation. In 159 patients with nonmetastatic disease at diagnosis, stage III disease (OR 3.88 [95% CI: 1.13-13.3]; p = .03) and the presence of perineural invasion (PNI) (OR 6.63 [95% CI: 2.21-19.84]; p = .001) were risk factors associated with the development of metastatic disease. Among 94 patients with de novo metastatic disease, 43 (43%) and 12 (14%) patients harbored a KRAS or BRAF V600E mutation, respectively. The median overall survival was 29.6 months (95% CI: 20.4-38.7). BRAF mutation was associated with inferior survival (HR 3.00 [95% CI: 1.30-6.94]; p = .01).

CONCLUSION

The prevalence of KRAS and BRAF mutations in our cohort is similar to the overseas experience. Stage III disease at diagnosis, presence of PNI and BRAF mutation are adverse prognostic indicators. A better understanding of the molecular landscape is needed for this patient cohort, so as to better tailor prevention strategies, screening and treatment pathways.

Gut Dysbiosis and Intestinal Barrier Dysfunction: Potential Explanation for Early-Onset Colorectal Cancer

Colorectal cancer (CRC) is a heterogeneous disease that commonly affects individuals aged more than 50 years old globally. Regular colorectal screening, which is recommended for individuals aged 50 and above, has decreased the number of cancer death toll over the years. However, CRC incidence has increased among younger population (below 50 years old). Environmental factors, such as smoking, dietary factor, urbanization, sedentary lifestyle, and obesity, may contribute to the rising trend of early-onset colorectal cancer (EOCRC) because of the lack of genetic susceptibility. Research has focused on the role of gut microbiota and its interaction with epithelial barrier genes in sporadic CRC. Population with increased consumption of grain and vegetables showed high abundance of Prevotella, which reduces the risk of CRC. Microbes, such as Fusobacterium nucleatum, Bacteroides fragilis and Escherichia coli deteriorate in the intestinal barrier, which leads to the infiltration of inflammatory mediators and chemokines. Gut dysbiosis may also occur following inflammation as clearly observed in animal model. Both gut dysbiosis pre- or post-inflammatory process may cause major alteration in the morphology and functional properties of the gut tissue and explain the pathological outcome of EOCRC. The precise mechanism of disease progression from an early stage until cancer establishment is not fully understood. We hypothesized that gut dysbiosis, which may be influenced by environmental factors, may induce changes in the genome, metabolome, and immunome that could destruct the intestinal barrier function. Also, the possible underlying inflammation may give impact microbial community leading to disruption of physical and functional role of intestinal barrier. This review explains the potential role of the interaction among host factors, gut microenvironment, and gut microbiota, which may provide an answer to EOCRC.

Prevalence of KRAS, PIK3CA, BRAF and AXIN2 gene mutations in colorectal cancer and its relationship with dental agenesis: a systematic review

Introduction: The study of allelic and genotypic frequencies contributes to determining the distribution of genetic variants in different populations and their possible association with biomarkers. This knowledge could improve the decision-making process regarding the management of some diseases such as colorectal cancer (CRC), in which the detection of clinical biomarkers such as dental agenesis could be crucial in clinical practice. Objective: To evaluate the available scientific evidence on the prevalence of KRAS, PIK3CA, BRAF and AXIN2 mutations and their possible association with dental agenesis in people with CRC. Materials and methods: A systematic search was conducted in PubMed, EMBASE and Cochrane Library databases using the following search strategy: type of studies: observational studies reporting the prevalence of KRAS, PIK3CA, BRAF and AXIN2 mutations in people diagnosed with CRC and their possible association with dental agenesis; publication language: English and Spanish; publication period: 2010-2020; search terms: “Genes”, “RAS”, “Kras”, “PIK3CA”, “BRAF”, “AXIN2”, “Mutation”, “Polymorphism”, “Colorectal Neoplasms”, “Colorectal Cancer”, used in different combinations (“AND” and “OR”).   Results: The initial search yielded 403 records, but only 30 studies met the eligibility criteria. Of these, 11, 5, 5 and 1 only reported the prevalence of PIK3CA, KRAS, BRAF and AXIN2 mutations, respectively; while 8 reported the prevalence of more than one of these mutations in patients with CRC. The prevalence of KRAS (p.Gly12Asp), PIK3CA (p.Glu545Lys), and BRAF (p.Val600Glu) mutations ranged from 20.5% to 54%, 3.5% to 20.2%, and 2.5% to 12.1%, respectively. There were no findings regarding the association between the occurrence of these mutations and dental agenesis.   Conclusions: KRAS mutations were the most prevalent; however, there is no evidence on the association between dental agenesis and the occurrence of KRAS, PIK3CA and BRAF germline mutations in individuals with CRC.

Utility of tumor-informed circulating tumor DNA in the clinical management of gastrointestinal malignancies

BACKGROUND

Gastrointestinal (GI) malignancies represent a heterogeneous group of diseases. Traditional tumor markers, though part of standard-of-care, lack sensitivity and specificity. Tumor-informed circulating tumor DNA (ctDNA) assay-based molecular residual disease assessment as well as recurrence and treatment response monitoring can serve as a robust tool in patients with wide range of GI malignancies and ethnicities.

METHODS

A personalized, tumor-informed multiplex PCR-NGS assay (SignateraTM) was used for the detection and quantification of ctDNA in 258 plasma samples from 198 patients with GI cancers at two institutions. Serial time- points were collected on a subset of patients (n=64) to monitor their ctDNA levels in response to treatment. Chi-square test was used to compare ctDNA-positivity rates in different cohorts.

RESULTS

The study included stage I-IV patients with a median age of 62 years (61% females and 49% ethnic minorities); 92% had surgical resection, 83% received systemic treatment. ctDNA-positivity was significantly associated with advanced stage (P=0.004), and presence/extent of metastases (P<0.00003). Serial time-point analysis showed that 22% (14/64) patients cleared ctDNA following treatment. ctDNA was detected in all patients who recurred (4/4; 100% sensitivity).

CONCLUSIONS

Serial monitoring of ctDNA using a tumor-informed ctDNA assay can be prognostic and predictive in advanced GI malignancies in adjuvant setting.

Clinicopathological characteristics of early onset colorectal cancer

BACKGROUND

The rising incidence of early onset colorectal cancer (EOCRC) might reflect a novel tumour entity.

AIMS

To evaluate clinicopathological characteristics of sporadic EOCRC (in patients < 50 years old) and investigate changes over time METHODS: All patients with sporadic EOCRC between 1989 and 2016 were included and divided by age: 20-29 years (group I), 30-39 years (group II) and 40-49 years (group III).

RESULTS

We included 6400 patients. The presence of signet-ring cells and more poorly differentiated tumours were more common in the younger age groups: 5.4% and 3.7% for signet-ring cells in group I and II vs 1.4% in group III (P < 0.01), and 28.5% and 20.3% for poorly differentiated in group I and II vs 16.6% in group III, (P < 0.01 group I; P = 0.07 group II). Positive lymph nodes were more frequently observed in the younger age groups: 16.2% in group I vs 9.3% in group II (P = 0.01) and 7.9% (P < 0.01) in group III. Over time, a greater proportion of CRCs were diagnosed in women in group I (34.5% < 2004 vs 54.9%>2005, P = 0.09), and a higher percentage of rectal cancer was found in age group III (34.3% < 2004 vs 40.7% > 2005, P < 0.01). Mean overall survival was 6.3 years and improved over time.

CONCLUSIONS

EOCRC is not only characterised by age of onset but also by the more frequent presence of signet-ring cells, more poorly differentiated tumours, and higher risk of lymph node metastases. In the most recent years, a higher proportion of rectal cancer was found from the age of 30 years, and a higher proportion of CRCs were diagnosed in females below the age of 30 years.

Analyzing the Opportunities to Target DNA Double-Strand Breaks Repair and Replicative Stress Responses to Improve Therapeutic Index of Colorectal Cancer

Despite the ample improvements of CRC molecular landscape, the therapeutic options still rely on conventional chemotherapy-based regimens for early disease, and few targeted agents are recommended for clinical use in the metastatic setting. Moreover, the impact of cytotoxic, targeted agents, and immunotherapy combinations in the metastatic scenario is not fully satisfactory, especially the outcomes for patients who develop resistance to these treatments need to be improved. Here, we examine the opportunity to consider therapeutic agents targeting DNA repair and DNA replication stress response as strategies to exploit genetic or functional defects in the DNA damage response (DDR) pathways through synthetic lethal mechanisms, still not explored in CRC. These include the multiple actors involved in the repair of DNA double-strand breaks (DSBs) through homologous recombination (HR), classical non-homologous end joining (NHEJ), and microhomology-mediated end-joining (MMEJ), inhibitors of the base excision repair (BER) protein poly (ADP-ribose) polymerase (PARP), as well as inhibitors of the DNA damage kinases ataxia-telangiectasia and Rad3 related (ATR), CHK1, WEE1, and ataxia-telangiectasia mutated (ATM). We also review the biomarkers that guide the use of these agents, and current clinical trials with targeted DDR therapies.

Expression of Immuno-Oncologic Biomarkers Is Enriched in Colorectal Cancers and Other Solid Tumors Harboring the A59T Variant of KRAS

The molecular heterogeneity of KRAS is well established, with a pool of variants comprising >75% of all known mutations; this pool includes mutations in classic codons 12, 13, and 61, as well as 146 and 117. In addition, there are rare variants that are more frequently encountered clinically due to the advances in next-generation sequencing and more widespread implementation of All-RAS sequencing over the past five years. We have previously identified a missense variant of KRAS, A59T, in a patient with CRC that was associated with a response to an epidermal growth factor inhibitor when added to chemotherapy, supporting the hypothesis that distinct biochemical impacts of different KRAS mutations may produce varied responses to targeted therapy. In this study, we explored a large genomic database comprising 17,909 cases of CRC to determine the prevalence of the A59T mutation and characterized the concurrent genomic alterations associated with this variant in more detail, particularly in relation to the expanding set of potential predictive immuno-oncologic biomarkers. We identified 14 cases of A59 mutations in this dataset (0.08% prevalence). We evaluated the prevalence of high tumor mutation burden (TMB), positive PD-L1 expression, and microsatellite instability-high/mismatch repair-deficiency (MSI-H/dMMR) using both next generation sequencing (NGS) and immunohistochemistry (IHC). The genomic features of pertinent signaling pathways were also described, including RAS pathway, chromatin remodeling, DDR, hedgehog signaling, PI3K, receptor tyrosine kinases, signal transduction, TGF-beta, TP53, and WNT. We uncovered a high level of association of predictive markers of responsiveness to checkpoint inhibition and potentially other forms of immunotherapy, with nearly half of all cases harboring microsatellite instability as assessed using NGS. A59T was also detected in 11 additional cancer types, most prominently in cases of gynecologic or other gastrointestinal sites of origin. This study provides supportive evidence that A59T, and possibly other similarly rare KRAS variants, co-occur with predictive biomarkers of response to immunotherapy.

Recent Updates on the Significance of KRAS Mutations in Colorectal Cancer Biology

The most commonly mutated isoform of RAS among all cancer subtypes is KRAS. In this review, we focus on the special role of KRAS mutations in colorectal cancer (CRC), aiming to collect recent data on KRAS-driven enhanced cell signalling, in vitro and in vivo research models, and CRC development-related processes such as metastasis and cancer stem cell formation. We attempt to cover the diverse nature of the effects of KRAS mutations on age-related CRC development. As the incidence of CRC is rising in young adults, we have reviewed the driving forces of ageing-dependent CRC.

Clinical, Pathological and Molecular Characteristics of Chilean Patients with Early-, Intermediate- and Late-Onset Colorectal Cancer

Colorectal cancer (CRC) is the second most frequent neoplasm in Chile and its mortality rate is rising in all ages. However, studies characterizing CRC according to the age of onset are still lacking. This study aimed to identify clinical, pathological, and molecular features of CRC in Chilean patients according to the age of diagnosis: early- (≤50 years; EOCRC), intermediate- (51–69 years; IOCRC), and late-onset (≥70 years; LOCRC). The study included 426 CRC patients from Clinica Las Condes, between 2007 and 2019. A chi-square test was applied to explore associations between age of onset and clinicopathological characteristics. Body Mass Index (BMI) differences according to age of diagnosis was evaluated through t-test. Overall (OS) and cancer-specific survival (CSS) were estimated by the Kaplan–Meier method. We found significant differences between the age of onset, and gender, BMI, family history of cancer, TNM Classification of Malignant Tumors stage, OS, and CSS. EOCRC category was characterized by a family history of cancer, left-sided tumors with a more advanced stage of the disease but better survival at 10 years, and lower microsatellite instability (MSI), with predominant germline mutations. IOCRC has shown clinical similarities with the EOCRC and molecular similarities to the LOCRC, which agrees with other reports.

Colorectal cancer of the young displays distinct features of aggressive tumor biology: A single-center cohort study

BACKGROUND

In recent years, a decrease in incidence and mortality of colorectal cancer (CRC) has been observed in developed nations, presumably through public disease awareness and increased screening efforts. However, a rising incidence of CRC in young patients below the age of 50 years has been reported in several studies.

AIM

To study tumor biology in CRC patients below 50 years of age.

METHODS

All patients with CRC were prospectively enrolled in our single-center oncologic database from January 2013 to December 2018 and were grouped and analyzed according to age (≥ 50 and < 50 years). Clinical as well as histopathological features were analyzed and compared. The study was approved by the local Ethics Committee. Fisher’s exact test or t-test was used to test for differences between the groups, as appropriate. All statistical analysis was performed with IBM SPSS software Version 25 (SPSS Inc, Armonk, NY, United States) and with R-Studio using R Version 3.4.1 (RStudio, Boston, MA, United States).

RESULTS

Seventeen percent of the 411 patients were younger than 50 years. Young patients were more often diagnosed with locally advanced T4-tumors and lymph node metastases (36.6% and 62% vs 17.7% and 42%; P < 0.01). In addition, a higher frequency of poorly differentiated (G3) tumors (40% vs 22.4% P < 0.05) was observed. More than every second patient below 40 years of age (51.8%) had distant metastases at diagnosis with a significant higher rate ring of signet cell differentiation compared to patients ≥ 50 years (14.8%, P < 0.05). Mutational status (KRAS, NRAS, BRAF, MSI) as well as selected behavioral risk factors showed no significant differences.

CONCLUSION

Distinct histopathologic features of increased biologic aggressiveness are found in patients with CRC of young-onset. Those patients present more frequently with more advanced tumor stages compared to older patients. Features of aggressive tumor biology underscore the need for earlier uptake of routine screening measures.

Differences in Pathology and Mutation Status Among Colorectal Cancer Patients Younger Than, Older Than, and of Screening Age

BACKGROUND

Screening protocols for colorectal cancer are broadly recommended and effective in reducing mortality. However, populations from different age groups can harbor distinct pathologic and molecular profiles that can also be influenced by screening and polyp resection, especially in older ages.

PATIENTS AND METHODS

We retrospectively analyzed tumors from stage IV colorectal cancer patients from a central pathology laboratory in Brazil that is a reference for mutational profiling countrywide. Patients were classified into age groups as follows: prescreening age (PrSA; < 45 years old), screening age (SA; 45-75 years old), and postscreening age (PoSA; > 75 years old). Every tumor was centrally reviewed by the pathologist. Groups were compared regarding clinicopathologic features, and the presence of RAS (renin-angiotensin system) and BRAF (v-Raf murine sarcoma viral oncogene homolog B) mutations.

RESULTS

We included 1635 patients (215 PrSA, 1213 SA, 207 PoSA). There was no difference among groups regarding sidedness (P = .65) and KRAS (Kirsten rat sarcoma viral oncogene) mutations (P = .57). Stage IV disease at diagnosis (P = .04), the presence of a signet-ring cell component (P < .001), and poorly differentiated tumors (P = .02) were most common in young patients, while BRAF and NRAS (neuroblastoma RAS viral (v-ras) oncogene homolog) mutations were significantly more common among PoSA patients (P = .002 and .03, respectively). When divided by age decade, KRAS mutations seem to have a stable frequency among all ages, while the BRAF mutation rate increased with increasing age.

CONCLUSION

BRAF mutations are more frequent among PoSA patients, and this seems to be a continuous trend. PrSA and PoSA patients seem to present a distinct profile from SA, including differences in molecular and pathologic aspects. These findings could impact the frequency of screening tests among different age groups.

Early-onset colorectal cancer: initial clues and current views

Over the past several decades, the incidence of early-onset colorectal cancer (EOCRC; in patients <50 years old) has increased at an alarming rate. Although robust and scientifically rigorous epidemiological studies have sifted out environmental elements linked to EOCRC, our knowledge of the causes and mechanisms of this disease is far from complete. Here, we highlight potential risk factors and putative mechanisms that drive EOCRC and suggest likely areas for fruitful research. In addition, we identify inconsistencies in the evidence implicating a strong effect of increased adiposity and suggest that certain behaviours (such as diet and stress) might place nonobese and otherwise healthy people at risk of this disease. Key risk factors are reviewed, including the global westernization of diets (usually involving a high intake of red and processed meats, high-fructose corn syrup and unhealthy cooking methods), stress, antibiotics, synthetic food dyes, monosodium glutamate, titanium dioxide, and physical inactivity and/or sedentary behaviour. The gut microbiota is probably at the crossroads of these risk factors and EOCRC. The time course of the disease and the fact that relevant exposures probably occur in childhood raise important methodological issues that are also discussed.

Nomogram predicting cancer-specific mortality in early-onset rectal cancer: a competing risk analysis

BACKGROUND

The incidence of rectal cancer has meaningfully increased in young patients. However, quantitative evaluation for the competing data of early-onset rectal cancer is lacking. So, we performed a competing risk analysis to calculate the cumulative incidence of death for patients with early-onset rectal cancer and developed a nomogram to predict the probability of cancer-specific mortality for these patients.

METHODS

We abstracted data of patients with early-onset rectal cancer between 2004 and 2016 by using the Surveillance, Epidemiology, and End Results program database. The cumulative incidence function was used to calculate the crude cancer-specific mortality of early-onset rectal cancer. Fine and Gray's proportional sub-distribution hazard model was adopted to explore the risk factors of cancer-specific death. Then, we establish a nomogram to predict their 3-, 5-, and 10-year probabilities.

RESULTS

We identified 9917 patients with early-onset rectal cancer, and they were randomly divided into training (n = 6941) and validation (n = 2976) cohorts. In the training cohort, the 3-, 5-, and 10-year cumulative incidences of cancer-specific death after diagnosis for early-onset rectal cancer were 11.4%, 19.9%, and 28.8%, respectively. Fine and Gray's model showed that sex, race, marital status, histology, T stage, N stage, M stage, examined lymph nodes, and pretreatment carcinoembryonic antigen were independently associated with cancer-specific mortality. Such factors were selected to develop a prognostic nomogram.

CONCLUSION

The competing risk nomogram has an ideal performance for predictive cancer-specific mortality in early-onset rectal cancer.

Demographic trends in the incidence of young-onset colorectal cancer: a population-based study

Background

Evidence is emerging that the incidence of colorectal cancer is increasing in young adults, but the descriptive epidemiology required to better understand these trends is currently lacking.

Methods

A population‐based cohort study was carried out including all adults aged 20–49 years diagnosed with colorectal cancer in England between 1974 and 2015. Data were extracted from the National Cancer Registration and Analysis Service database using ICD‐9/10 codes for colorectal cancer. Temporal trends in age‐specific incidence rates according to sex, anatomical subsite, index of multiple deprivation quintile and geographical region were analysed using Joinpoint regression.

Results

A total of 56 134 new diagnoses of colorectal cancer were analysed. The most sustained increase in incidence rate was in the group aged 20–29 years, which was mainly driven by a rise in distal tumours. The magnitude of incident rate increases was similar in both sexes and across Index of Multiple Deprivation quintiles, although the most pronounced increases in incidence occurred in the southern regions of England.

Conclusion

Colorectal cancer should no longer be considered a disease of older people. Changes in incidence rates should be used to inform future screening policy, preventative strategies and research agendas, as well as increasing public understanding that younger people need to be aware of the symptoms of colorectal cancer.

Colorectal Cancer in the Young: Epidemiology, Prevention, Management

Colorectal cancer (CRC) incidence rates in the United States overall have declined since the mid-1980s because of changing patterns in risk factors (e.g., decreased smoking) and increases in screening. However, this progress is increasingly confined to older adults. CRC occurrence has been on the rise in patients younger than age 50, often referred to as early-onset disease, since the mid-1990s. Young patients are more often diagnosed at an advanced stage and with rectal disease than their older counterparts, and they have numerous other unique challenges across the cancer management continuum. For example, young patients are less likely than older patients to have a usual source of health care; often need a more complex treatment protocol to preserve fertility and sexual function; are at higher risk of long-term and late effects, including subsequent primary malignancies; and more often suffer medical financial hardship. Diagnosis is often delayed because of provider- and patient-related factors, and clinicians must have a high index of suspicion if young patients present with rectal bleeding or changes in bowel habits. Educating primary care providers and the larger population on the increasing incidence and characteristic symptoms is paramount. Morbidity can further be averted by increasing awareness of the criteria for early screening, which include a family history of CRC or polyps and a genetic predisposition.

Comprehensive characterization of RAS mutations in colon and rectal cancers in old and young patients

Colorectal cancer (CRC) is increasingly appreciated as a heterogeneous disease, with factors such as microsatellite instability (MSI), cancer subsite within the colon versus rectum, and age of diagnosis associated with specific disease course and therapeutic response. Activating oncogenic mutations in KRAS and NRAS are common in CRC, driving tumor progression and influencing efficacy of both cytotoxic and targeted therapies. The RAS mutational spectrum differs substantially between tumors arising from distinct tissues. Structure-function analysis of relatively common somatic RAS mutations in G12, Q61, and other codons is characterized by differing potency and modes of action. Here we show the mutational profile of KRAS, NRAS, and the less common HRAS in 13,336 CRC tumors, comparing the frequency of specific mutations based on age of diagnosis, MSI status, and colon versus rectum subsite. We identify mutation hotspots, and unexpected differences in mutation spectrum, based on these clinical parameters.

Activating oncogenic mutations in KRAS and NRAS are common in colorectal cancer, which is a heterogenous disease. Here, the authors show that the RAS mutation spectrum is markedly different between colon and rectal cancer, and also different based on age of diagnosis and microsatellite instability.

Colorectal cancer screening from 45 years of age: Thesis, antithesis and synthesis

Colorectal cancer incidence and mortality in patients younger than 50 years are increasing, but screening before the age of 50 is not offered in Europe. Advanced-stage diagnosis and mortality from colorectal cancer before 50 years of age are increasing. This is not a detection-bias effect; it is a real issue affecting the entire population. Three independent computational models indicate that screening from 45 years of age would yield a better balance of benefits and risks than the current start at 50 years of age. Experimental data support these predictions in a sex- and race-independent manner. Earlier screening is seemingly affordable, with minimal impediments to providing younger adults with colonoscopy. Indeed, the American Cancer Society has already started to recommend screening from 45 years of age in the United States. Implementing early screening is a societal and public health problem. The three independent computational models that suggested earlier screening were criticized for assuming perfect compliance. Guidelines and recommendations should be derived from well-collected and reproducible data, and not from mathematical predictions. In the era of personalized medicine, screening decisions might not be based solely on age, and sophisticated prediction software may better guide screening. Moreover, early screening might divert resources away from older individuals with greater biological risks. Finally, it is still unknown whether early colorectal cancer is part of a continuum of disease or a biologically distinct disease and, as such, it might not benefit from screening at all. The increase in early-onset colorectal cancer incidence and mortality demonstrates an obligation to take actions. Earlier screening would save lives, and starting at the age of 45 years may be a robust screening option.

Clinical and molecular characterization of early-onset colorectal cancer

BACKGROUND

Colorectal cancer (CRC) incidence is increasing in adults younger than 50 years. This study evaluated clinical and molecular features to identify those features unique to early-onset CRC that differentiate these patients from patients 50 years old or older.

METHODS

Baseline characteristics were evaluated according to the CRC onset age with 3 independent cohorts. A fourth cohort was used to describe the impact of age on the consensus molecular subtype (CMS) prevalence.

RESULTS

This retrospective review of more than 36,000 patients with CRC showed that early-onset patients were more likely to have microsatellite instability (P = .038), synchronous metastatic disease (P = .009), primary tumors in the distal colon or rectum (P < .0001), and fewer BRAF V600 mutations (P < .001) in comparison with patients 50 years old or older. Patients aged 18 to 29 years had fewer adenomatous polyposis coli (APC) mutations (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.35-0.90; P = .015) and an increased prevalence of signet ring histology (OR, 4.89; 95% CI, 3.23-7.39; P < .0001) in comparison with other patients younger than 50 years. In patients younger than 40 years, CMS1 was the most common subtype, whereas CMS3 and CMS4 were uncommon (P = .003). CMS2 was relatively stable across age groups. Early-onset patients with inflammatory bowel disease were more likely to have mucinous or signet ring histology (OR, 5.54; 95% CI, 2.24-13.74; P = .0004) and less likely to have APC mutations (OR, 0.24; 95% CI, 0.07-0.75; P = .019) in comparison with early-onset patients without predisposing conditions.

CONCLUSIONS

Early-onset CRC is not only distinct from traditional CRC: special consideration should be given to and further investigations should be performed for both very young patients with CRC (18-29 years) and those with predisposing conditions. The etiology of the high rate of CMS1 in patients younger than 40 years deserves further exploration.

Early-onset colorectal cancer in young individuals

Treatment of young adults with colorectal cancer (CRC) represents an unmet clinical need, especially as diagnosis in this population might lead to the greatest loss of years of life. Since 1994, CRC incidence in individuals younger than 50 years has been increasing by 2% per year. The surge in CRC incidence in young adults is particularly alarming as the overall CRC frequency has been decreasing. Early-onset CRC are characterized by a more advanced stage at diagnosis, poorer cell differentiation, higher prevalence of signet ring cell histology, and left colon-sided location of the primary tumor. Among EO-CRC, approximately 30% of patients are affected by tumors harboring mutations causing hereditary cancer predisposing syndromes, and 20% have familial CRC. Most notably, the remaining 50% of EO-CRC patients have neither hereditary syndromes nor familial CRC, thus representing a formidable challenge for research. In this review article we summarize epidemiology, clinical and molecular features, heredity and outcome of treatments of EO-CRC, and provide considerations for future perspectives.

Early onset sporadic colorectal cancer: Worrisome trends and oncogenic features

Early onset colorectal cancers, defined as arising before 50 years of age, are a growing health hazard in western and eastern countries alike. The incidence of colon and rectal cancers in young individuals is projected to increase by as much as 90% and 140%, respectively, by 2030. Although several known cancer risk factors (e.g. smoking, alcohol, dietary habits) have been investigated, there is no single compelling explanation for this epidemiological trend. While some early onset colorectal cancers have been associated with germline mutations in cancer predisposition genes, genetic syndromes are implicated in only a fraction of these cancers (20%) and do not explain the rising incidence. Colorectal neoplasms develop through microsatellite instability or chromosomal instability pathways, with most of the early onset colorectal cancers exhibiting microsatellite stable phenotypes. Genome-wide hypomethylation is a feature of a subgroup of early onset cancers, which appears to be correlated with chromosomal instability and poor prognosis.

Genomic profiling of intestinal-type sinonasal adenocarcinoma reveals subgroups of patients with distinct clinical outcomes

BACKGROUND

Patients with intestinal-type sinonasal adenocarcinoma (ITAC) have an unfavorable prognosis and new therapeutic approaches are needed to improve clinical management.

METHODS

Genetic analysis of 96 ITACs was performed by microarray comparative genomic hybridization and immunohistochemistry and correlated to previously obtained mutation, methylation, and protein expression data, and with pathological characteristics and clinical outcome.

RESULTS

Seven copy number alterations (CNAs) were significantly associated with unfavorable clinical outcome: gains at 1q22-23, 3q28-29, 6p22, and 13q31-33, and losses at 4p15-16, 4q32-35, and 10q24. Unsupervised cluster analysis resulted in 5 subgroups of ITAC with significantly distinct genetic signatures and clinical outcomes, independently of disease stage or histological subtype.

CONCLUSION

These data may guide studies to identify driver genes and signaling pathways involved in ITAC. In addition, the subclassification of genetic subgroups of patients with distinct clinical behavior can aid therapeutic decision making and may ultimately lead to personalized therapy with targeted inhibitors.