Colorectal cancer in young adults: A difficult challenge

Lipid Metabolism as a Targetable Metabolic Vulnerability in Colorectal Cancer

Colorectal cancer (CRC), the second leading cause of cancer-related deaths according to the World Health Organization, remains a substantial public health problem worldwide [...].

A Young Male With Anorexia, Abdominal Complaints and Marked Blood Eosinophilia

Peripheral blood eosinophilia represents a frequent finding in routine clinical practice when absolute eosinophil count is found to be greater than 0.5 x 109/L (500/µL). Common causes include parasitic infections, allergic reactions, and hyper-eosinophilic syndrome. Eosinophilia secondary to malignancy represents an uncommon presentation.

Here we report an atypical case of a 47-year-old previously healthy male who presented to a primary care setting complaining of fatigue and anorexia for the last two weeks. The evaluation revealed leucocytosis and peripheral hypereosinophilia with an absolute eosinophil count of 14.13×109/L (37%).

Following an extensive diagnostic work in a secondary care centre he was finally diagnosed with rectal carcinoma. This case highlights that solid malignancy should be considered in patients with marked peripheral eosinophilia.

Patients with early-onset rectal cancer aged 40 year or less have similar oncologic outcomes to older patients despite presenting in more advanced stage; A retrospective cohort study

BACKGROUND

Early-onset colon and rectal cancer has increased in alarming rates. The present study reviewed the characteristics and outcome of early-onset rectal cancer in patients aged ≤40 years.

METHODS

This was a retrospective cohort study on rectal cancer patients who were treated in a tertiary center in the Middle East. Baseline characteristics and outcomes of patients ≤40 years were compared with patients >40 years. Main outcome measures were patients' and tumor characteristics, local recurrence, distance metastasis, overall survival (OS), and disease-free survival (DFS).

RESULTS

Among 244 patients with rectal cancer, 81 (33.2%) aged 40 years or less. 56.8% of patients ≤40 years and 49.7% of patients >40 years presented with stage III/IV disease (p = 0.36). Local recurrence and distant metastasis were detected in 10.3% and 13.2% of patients ≤40 years and in 16.9% and 13.9% of patients >40 years (p = 0.29 and 0.88). The 3-year OS and DFS rates of patients ≤40 years were 75% and 80.9% versus 74.2% and 76.5% in patients >40 years (p = 0.9 and 0.59). Patients ≤40 years presented with ulcerative carcinoma (38.3% vs 21.5%, p = 0.01) and signet-ring carcinoma (12.3% vs 2.5%, p = 0.008) more than patients > 40 years.

CONCLUSION

Early-onset rectal cancer accounted for one-third of all patients presenting with rectal cancer. Patients younger than 40 years had higher incidence of mucinous and signet-ring rectal carcinoma, and presented more with advanced stage. The age of patients did not have a significant impact on the oncologic outcome of rectal cancer.

Descriptive epidemiological study of South African colorectal cancer patients at a Johannesburg Hospital Academic institution

BACKGROUND AND AIM

Epidemiological studies of colorectal cancer (CRC) in South Africa (SA) have been poorly characterized. Black and white SA population groups have demonstrated distinct CRC clinical presentations, suggesting that black SA patients follow a different carcinogenic pathway than their white counterparts. Thus, the aim of this study was to identify unique demographic and histopathological features associated with black SA patients to facilitate earlier diagnosis and to improve disease management.

METHODS

This preliminary descriptive epidemiological study included 665 retrospective CRC cases diagnosed between the period 2011 and 2015 at the Charlotte Maxeke Johannesburg Academic Hospital. Demographic and histopathological features in black versus other race groups (ORG) were compared, and Student's t-test, Chi-square, and Fischer's exact tests were used for statistical analysis.

RESULTS

Statistical analysis demonstrated that patients with left-sided tumors of invasive adenocarcinoma were predominantly black and male. These patients were considerably younger when compared to ORG (median 56 vs 62 years, respectively), P < 0.0001. However, no significant propensity for other histological features was illustrated. Polyps were mostly tubular adenomas (51%) and tubulovillous adenomas (TVAs) (44%). TVAs were mostly high-grade lesions (P < 0.0001) and associated with left-sided CRC (P = 0.0325).

CONCLUSION

These findings verify that black SA CRC patients have an earlier disease onset in comparison to ORG; however, no increased tendency for tumor site, precursor lesion, stage of disease, or gender was evident. Thus, a deeper molecular characterization of CRC is required to understand the underlying causes associated with earlier disease onset in black SA CRC patients.

Increased incidence of early onset colorectal adenocarcinoma is accompanied by an increased incidence of rectal neuroendocrine tumors

Recent studies have reported an increasing incidence of early onset colorectal cancer (CRC). Few studies compared the changing incidence of CRC by the major histological type, adenocarcinoma and neuroendocrine tumors (NETs). Using data from the Surveillance, Epidemiology, and End Results Program (SEER), we identified CRC from 1992 to 2015 with site and histological codes. Standardized incidence rates of CRC by anatomical locations (proximal, distal and rectal colon) and histological types (adenocarcinoma, NETs and others) were calculated over calendar years. Annual percent changes (APC) and joint-point regression were further computed. A significant increase of cancers in the distal colon and rectum was observed in young populations (20-44 and 45-54 years) but not in the proximal colon. Further analyses found that the highest rise of rectal NETs was in the 45-54 years which contributed 53.47% to the total increase of rectal cancer. The APCs for NETs in the rectum were 2.9 (95% CI: -0.1, 6.0) and 6.1 (95% CI: 3.8-8.4) for 20-44 years or 45-54 years respectively. The increase of NETs in the rectum was still significant in the older than 55 years (APC=3.7, 95% CI: 2.8-4.7), although the total CRC in this group was decreasing. Incidence of NETs in the distal colon is not apparently changing. The increase of CRC incidence among young populations (age < 55) is mainly due to the increased incidence in the rectum and distal colon. Moreover, the increase of early onset cancer in the rectum could be ascribed to increased incidence of adenocarcinoma and NETs.

Trends in the epidemiology of young-onset colorectal cancer: a worldwide systematic review

BACKGROUND

Recent data suggest that the risk of young-onset colorectal cancer (yCRC), in adults less than 50 years of age, is increasing. To confirm findings and identify contemporary trends worldwide, we conducted a systematic review of studies examining population-level trends in yCRC epidemiology.

METHODS

We searched MEDLINE (1946-2018), EMBASE (1974-2018), CINAHL (1982-2018), and Cochrane Database of Systematic Reviews (2005-2018) for studies that used an epidemiologic design, assessed trends in yCRC incidence or prevalence, and published in English. Extracted information included country, age cut-off for yCRC, and reported trends in incidence or prevalence (e.g. annual percent change [APC]). We pooled similarly reported trend estimates using random effects models.

RESULTS

Our search yielded 8695 articles and after applying our inclusion criteria, we identified 40 studies from 12 countries across five continents. One study assessed yCRC prevalence trends reporting an APCp of + 2.6 and + 1.8 among 20-39 and 40-49 year olds, respectively. 39 studies assessed trends in yCRC incidence but with substantial variability in reporting. Meta-analysis of the most commonly reported trend estimate yielded a pooled overall APCi of + 1.33 (95% CI, 0.97 to 1.68; p < 0.0001) that is largely driven by findings from North America and Australia. Also contributing to these trends is the increasing risk of rectal cancer as among 14 studies assessing cancer site, nine showed an increased risk of rectal cancer in adults less than 50 years with APCi up to + 4.03 (p < 0.001).

CONCLUSIONS

Our systematic review highlights increasing yCRC risk in North America and Australia driven by rising rectal cancers in younger adults over the past two decades.

Survival analysis of colorectal cancer patients in a Thai hospital-based cancer registry

Background: The study aimed to assess the overall and stage-specific colorectal cancer (CRC) survival and to identify the prognostic factors for survival among Thai patients.Research design and methods: The retrospective data of CRC patients from a university hospital-based cancer registry from 2001 to 2014 were used to estimate five-year overall survival (OS). Kaplan-Meier method and log-rank tests were used to assess the differences in five-year OS by age at diagnosis, diagnostic period, tumor site, stage at diagnosis and treatment modalities. A multivariate Cox's proportional hazard model was used to identify independent prognostic factors for the OS.Results: A total of 1,507 (48%) colon and 1,648 (52%) rectal cancer patients were included. Five-year OS for CRC patients was 44%. It differed significantly by stage, age group, and treatment received. Stage at diagnosis, age group, diagnostic period, receiving surgical and chemotherapy treatments were prognostic factors for OS.Conclusions: An increasing trend in the number of CRC patients mostly at stage III and IV was found. Our results emphasized that an improvement in CRC survival could be achieved through the adoption of advanced cancer therapies, as well as improved access to quality diagnosis and timely treatment.

NGS Evaluation of Colorectal Cancer Reveals Interferon Gamma Dependent Expression of Immune Checkpoint Genes and Identification of Novel IFNγ Induced Genes

To evaluate the expression of immune checkpoint genes, their concordance with expression of IFNγ, and to identify potential novel ICP related genes (ICPRG) in colorectal cancer (CRC), the biological connectivity of six well documented ("classical") ICPs (CTLA4, PD1, PDL1, Tim3, IDO1, and LAG3) with IFNγ and its co-expressed genes was examined by NGS in 79 CRC/healthy colon tissue pairs. Identification of novel IFNγ- induced molecules with potential ICP activity was also sought. In our study, the six classical ICPs were statistically upregulated and correlated with IFNγ, CD8A, CD8B, CD4, and 180 additional immunologically related genes in IFNγ positive (FPKM > 1) tumors. By ICP co-expression analysis, we also identified three IFNγ-induced genes [(IFNγ-inducible lysosomal thiol reductase (IFI30), guanylate binding protein1 (GBP1), and guanylate binding protein 4 (GBP4)] as potential novel ICPRGs. These three genes were upregulated in tumor compared to normal tissues in IFNγ positive tumors, co-expressed with CD8A and had relatively high abundance (average FPKM = 362, 51, and 25, respectively), compared to the abundance of the 5 well-defined ICPs (Tim3, LAG3, PDL1, CTLA4, PD1; average FPKM = 10, 9, 6, 6, and 2, respectively), although IDO1 is expressed at comparably high levels (FPKM = 39). We extended our evaluation by querying the TCGA database which revealed the commonality of IFNγ dependent expression of the three potential ICPRGs in 638 CRCs, 103 skin cutaneous melanomas (SKCM), 1105 breast cancers (BC), 184 esophageal cancers (ESC), 416 stomach cancers (STC), and 501 lung squamous carcinomas (LUSC). In terms of prognosis, based on Pathology Atlas data, correlation of GBP1 and GBP4, but not IFI30, with 5-year survival rate was favorable in CRC, BC, SKCM, and STC. Thus, further studies defining the role of IFI30, GBP1, and GBP4 in CRC are warranted.

Deregulation of cancer-stem-cell-associated miRNAs in tissues and sera of colorectal cancer patients

Colorectal cancer (CRC) is a deadly tumour in Western countries characterized by high cellular/molecular heterogeneity. Cancer stem cells (CSC) act in cancer recurrence, drug-resistance and in metastatic epithelial-to-mesenchymal transition. microRNAs (miRNAs) contribute to cancer is increasing, and miRNA roles in CSC phenotype and fate and their utility as CRC biomarkers have also been reported. Here, we investigated miR-21, miR-221, miR-18a, miR-210, miR-31, miR-34a, miR-10b and miR-16 expression in experimental ALDH⁺ and CD44⁺/CD326⁺ colorectal CSCs obtained from the human CRC cell lines HCT-116, HT-29 and T-84. Then, we moved our analysis in cancer tissue (CT), healthy tissue (HT) and serum (S) of adult CRC patients (n=12), determining relationships with clinical parameters (age, sex, metastasis, biochemical serum markers). Specific miRNA patterns were evident in vitro (normal, monolayers and CSCs) and in patients’ samples stratified by TNM stage (LOW vs HIGH) or metastasis (Met vs no-Met). miR-21, miR-210, miR-34a upregulation ad miR-16 dowregulation associated with the CSCs phenotype. miR-31b robustly overexpressed in monolayers and CSCs, and in CT ad S of HIGH grade and Met patients, suggesting a role as marker of CRC progression and metastasis. miR-18a upregulated in all cancer models and associated to CSC phenotype, and to metastasis and age in patients. miR-10b downregulated in CT and S of LOW/HIGH grade and no-Met patients. Our results identify miRNAs useful as colorectal CSC biomarker and that miR-21, miR-210, miR-10b and miR-31b are promising markers of CRC. A specific role of miR-18a as metastatic CRC serum biomarker in adult patients was also highlighted.

Genetically Engineered Pigs to Study Cancer

Recent decades have seen groundbreaking advances in cancer research. Genetically engineered animal models, mainly in mice, have contributed to a better understanding of the underlying mechanisms involved in cancer. However, mice are not ideal for translating basic research into studies closer to the clinic. There is a need for complementary information provided by non-rodent species. Pigs are well suited for translational biomedical research as they share many similarities with humans such as body and organ size, aspects of anatomy, physiology and pathophysiology and can provide valuable means of developing and testing novel diagnostic and therapeutic procedures. Porcine oncology is a new field, but it is clear that replication of key oncogenic mutation in pigs can usefully mimic several human cancers. This review briefly outlines the technology used to generate genetically modified pigs, provides an overview of existing cancer models, their applications and how the field may develop in the near future.

The Association Between Inflammation, Epithelial Mesenchymal Transition and Stemness in Colorectal Carcinoma

Background

Inflammation plays an important albeit dual role in carcinogenesis. Survival studies have highlighted the prognostic significance of peritumorous inflammation. Currently, the theoretical background allows inflammation, epithelial mesenchymal transition (EMT) and the closely associated stem cell differentiation in colorectal carcinoma (CRC) to be linked. However, there is scarce direct morphological evidence.

Purpose and methods

The aim of our study was to investigate the role of inflammation in cancer growth and invasion by analyzing the association between inflammation and known morphological prognostic features of colorectal cancer, EMT, stemness and mismatch repair (MMR) protein expression. The study was designed as a retrospective morphological and immunohistochemical assessment of 553 consecutive cases of surgically treated primary CRC.

Results

There were statistically significant associations between high-grade inflammation and lower pT (p = 0.002), absence of lymph node metastases (p < 0.001) and less frequent lymphatic (p = 0.003), venous (p = 0.017), arterial (p = 0.012), perineural (p = 0.001) and intraneural (p = 0.01) invasion. In contrast, Crohn's like reaction (CLR) by density of lymphoid follicles in the invasive front lacked significant differences in regard to pT, pN, tumor invasion into surrounding structures (blood or lymphatic vessels, nerves), grade or necrosis (all p > 0.05). The expression of E-cadherin, CD44 and MMR proteins yielded no statistically significant associations with peritumorous inflammation by Klintrup-Mäkinen score or the density of lymphoid follicles. Nevertheless, E-cadherin levels were significantly associated with the density of eosinophils (p = 0.007).

Conclusion

High-grade peritumorous inflammation is associated with beneficial morphologic CRC features, including less frequent manifestations of invasion, and is not secondary to tissue damage and necrosis. CLR is not associated with cancer spread by pTN; this finding indirectly suggests an independent role of CLR in carcinogenesis. Further, inflammation by Klintrup-Mäkinen grade and CLR is not dependent on epithelial-mesenchymal transition and stem cell differentiation. Our study highlights the complex associations between inflammation, tumor morphology, EMT, stemness and MMR protein expression in human CRC tissues.

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.

Interleukin-24 Regulates T Cell Activity in Patients With Colorectal Adenocarcinoma

Interleukin (IL)-24 plays a potential anti-tumor activity in colorectal cancer in a dose-dependent manner. However, the immunoregulatory role of IL-24 to peripheral and tumor-infiltrating T cell function in colorectal cancer was not fully elucidated. In this study, twenty-nine colorectal adenocarcinoma patients and fifteen healthy individuals were enrolled. IL-24 expression and IL-24 receptor (IL-20R1, IL-20R2, and IL-22R1) mRNA relative level was measured by ELISA and real-time PCR, respectively. CD4⁺ and CD8⁺ T cells were purified from peripheral bloods and cancer specimens, and were stimulated with low (10 ng/ml) and high (100 ng/ml) concentration of recombinant IL-24. CD4⁺ T cells activity was assessed by measurement of Th cell percentage, transcriptional factors, and cytokine production. CD8⁺ T cells activity was evaluated by investigation of cytotoxic molecules, target cell death, and interferon-γ (IFN-γ) secretion. IL-24 was decreasingly expressed in both peripheral bloods and cancer tissues in colorectal adenocarcinoma patients. However, IL-20R1 and IL-20R2 was comparable between healthy controls and colorectal adenocarcinoma patients. Low concentration of IL-24 suppressed CD4⁺ T cell proliferation. In contrast, high concentration of IL-24 not only promoted CD4⁺ T cell proliferation, but also enhanced CD4⁺ T cell activity, which mainly presented as up-regulation of Th1/Th17 frequency, T-bet/RORγt mRNA, and IFN-γ/IL-17 production but down-regulation of Treg percentage, FoxP3 mRNA, and IL-10/IL-35 secretion. Moreover, high concentration of IL-24 also increased perforin and granzyme B expression in CD8⁺ T cells, and elevated cytolytic and non-cytolytic activity of CD8⁺ T cells, which presented as induction of target cell death and elevation of IFN-γ expression. However, low concentration of IL-24 did not affect bioactivity of CD8⁺ T cells. The current data indicated that IL-24 might regulate T cell function in a dose-dependent manner. High-concentration of IL-24 might promote anti-tumor immune responses in development novel therapeutic approaches to colorectal adenocarcinoma.

Clinicopathological features and survival of colorectal cancer patients younger than 50 years: a retrospective comparative study

BACKGROUND

Colorectal cancer (CRC) is a disease of old age, but its incidence has been rising among younger population compared to older ones. Nevertheless, there is a controversy over survival of younger patients compared to the older ones. Therefore, in the current study, we investigated the clinicopathological features and survival of the younger (< 50 years) versus older (≥ 50 years) CRC patients.

RESULTS

The younger and older groups consisted of 39.4% and 60.6% of patients, respectively. Both age groups were comparable regarding the symptom presentation and duration, and pre-operative carcinoembryonic antigen (CEA). The younger patients were diagnosed with a higher proportion of poorly differentiated (14.7% vs. 8.3%; p < 0.001) and more advanced tumors (53.2% vs. 45.9%; p = 0.266). The rectum tumor site was significantly more common among the younger patients (p = 0.021). The overall survival (OS) (p = 0.278), the cancer-specific survival (CSS) (p = 0.233), and the disease-free survival (DFS) (p = 0.497) did not differ significantly between the two groups. Based on Cox regression model, elevated pre-operative CEA level (HR = 1.41; 95%CI of 1.01-1.97), advanced tumor stage (6.06; 95%CI of 3.03-12.15), and poorly differentiated tumor (HR = 1.69; 95%CI of 1.05-2.71) were associated with decreased survival.

CONCLUSIONS

The younger patients did not have poor prognosis compared to the older ones despite having an advanced tumor stage and a poor tumor differentiation.

[Epidemiology, treatment and prognosis of colorectal cancer in young adults in sub-Saharan Africa]

Colorectal cancer is the most common digestive cancer. The objectives of this study was to analyse the frequency, aetiologies, and the therapeutic and progressive aspects of colorectal cancer in young adults in Burkina Faso. This study was a 10-years descriptive study conducted in 2 regional hospitals in Burkina Faso. It included all patients aged 20 to 45 years admitted to these two hospitals for colon cancer or rectal cancer during the study period. A total of 116 patients were included, which was 39.2% of all patients admitted for colorectal cancer during the same period. The average age of the included patients was 35.4 years old. There were 70 male patients (60.3%). Seven patients had a history of chronic inflammatory bowel disease, and six had a family history of colon cancer. The average consultation time was 6.2 months. In 25 cases (19.9%), the cancer was discovered in the context of an abdominal emergency. Ninety-two patients (79.3%) were diagnosed at stage 3 or stage 4 according to the TNM Staging System. The most common histological type was adenocarcinoma (103 cases, 88.9%). Therapeutically, surgery was performed on 87 patients (75%) and chemotherapy was used in 37 cases (31.9%). Sixteen patients received radiotherapy. The intra operative mortality rate was 4.6%. The 5-year survival rate was 17%. In conclusion, colorectal cancer in young adults occurs without obvious risk factors in Burkina Faso. Mortality remains high because of the limited therapeutic arsenal.

Serum Chemokine CXCL7 as a Diagnostic Biomarker for Colorectal Cancer

Identification of effective biomarkers is crucial for monitoring the treatment and remission of colorectal cancer (CRC) and improving survival. It is particularly important to diagnose CRC before the tumor metastasizes (stage I–II disease) where possible, to provide the greatest opportunity for patient recovery. Here, we evaluated the clinical value of serum chemokine (C-X-C) ligand 7 (CXCL7) concentration as a biomarker for CRC diagnosis. An enzyme-linked immunosorbent assay was used to measure CXCL7 concentration in 560 serum samples from patients with CRC and controls. Logistic regression and receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic efficacy and build mathematical diagnostic models. The concentration of CXCL7 in the CRC group was significantly higher than that in the control group (P < 0.001), with an area under the ROC curve (AUC) value of 0.862 [95% confidence interval (CI): 0.831–0.890]. Further, the AUC of a regression model including the markers carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and carbohydrate antigen 125 (CA125), along with CXCL7, was 0.933 (95% CI: 0.909–0.952). For stage I–II tumors, CXCL7 had the highest AUC (0.823, 95% CI: 0.783–0.858) among the four individual biomarkers. The AUC value for combination model analysis of samples from patients with stage I–II tumors was 0.904 (95% CI: 0.872–0.930), with a sensitivity of 82.76% and a specificity of 87.14%, and an optimal cut-off value of 2.66. AUC values for application of the regression model in subgroup analysis were 0.947 (0.917–0.968) and 0.919 (0.874–0.951) for males and females, respectively. These results suggest that CXCL7 has potential as a serum diagnostic biomarker for detection of CRC. Importantly, the combination of CXCL7, CEA, CA125, and CA19-9 may facilitate diagnosis of CRC with relatively high sensitivity and specificity.

Clinical Trial Registration Number: LS2017001.

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.

Global Increasing Incidence of Young-Onset Colorectal Cancer Across 5 Continents: A Joinpoint Regression Analysis of 1,922,167 Cases

BACKGROUND

Colorectal cancer incidence among young adults in the United States is on the rise, but whether this phenomenon is present in other parts of the world is not well documented. This study aims to explore the temporal change of incidence rates for colorectal cancer in various countries across the globe.

METHODS

We extracted colorectal cancer incidence and population data from 1988 to 2007 based on data from the International Agency for Research on Cancer and compared incidence between age groups. Twelve representative jurisdictions from five continents were selected. Young-onset colorectal cancer cases were defined as those ages <50 years. Joinpoint regression was used to measure the trends of colorectal cancer incidence and to estimate the annual percent change (APC).

RESULTS

The APC for those ages <50 years was noted to be increasing at a faster rate as compared with those ages ≥50 years in many regions, including Australia (+1.10% vs. -0.35%), Brazil (+9.20% vs. +5.72%), Canada (+2.60% vs. -0.91%), China-Hong Kong (+1.82% vs. -0.10%), China-Shanghai (+1.13% vs. -2.68%), Japan (+2.63% vs. +0.90%), the United Kingdom (+3.33% vs. +0.77%), and the United States (+1.98% vs. -2.88%). These trends were largely driven by rectal cancer, except in Brazil and the United Kingdom.

CONCLUSIONS

Increasing incidence of young-onset colorectal cancer was noted in many regions across the globe.

IMPACT

Further studies focusing on young-onset colorectal cancer, particularly with regard to risk factors and establishing the optimal age of screening, are warranted.

An Incidental Finding of Anemia: Rectal Adenocarcinoma in a Young Adult

Rectal adenocarcinoma is an uncommon finding in patients under the age of 40. However, epidemiological surveys have suggested that colorectal cancers are increasing in incidence among patients aged 20 to 39 years in the United States. Colorectal adenocarcinoma is often not considered in the differential diagnosis in this demographic because of age. Here, we present the case of an incidental finding of anemia during a preliminary evaluation of rheumatoid arthritis leading to the diagnosis of stage IV-B rectal adenocarcinoma in a 34-year-old male patient.

A 34-year-old Caucasian male presented with the incidental finding of anemia during a preliminary evaluation for rheumatoid arthritis. The patient was asymptomatic with the exception of a three-month history of wrist and ankle joint pain. Past medical history was positive for only a three-year history of occasional spotty, painless rectal bleeding attributed to internal hemorrhoids. Physical exam findings were positive for mild extremity pallor and positive fecal occult blood test. Hematologic studies revealed a significant microcytic, hypochromic anemia with severe iron deficiency. Laboratory studies revealed no evidence of vitamin deficiency, hemolytic activity, hematuria, hypothyroidism, or clotting factor disorder. Erythrocyte sedimentation rate (ESR), rheumatoid factor, and cyclic citrullinated peptide 3 (CCP3) were elevated supporting the diagnosis of underlying rheumatoid arthritis. On further questioning, the patient revealed that he had been utilizing an average of 2000 mg of ibuprofen daily during the previous several months in an attempt to control his joint pain. The patient was evaluated for a potential upper gastrointestinal bleed by esophagogastroduodenoscopy (EGD), which found no evidence of active bleeding. As the patient continued to have decreasing hemoglobin levels, he was evaluated for a lower gastrointestinal source of bleeding by colonoscopy, which revealed an 8 cm circumferential mass at the anal verge. Pathological evaluation of biopsy samples revealed a moderately differentiated invasive adenocarcinoma. The patient had no family history of colorectal cancer or major associated risk factors, such as obesity, smoking history, heavy alcohol use, diabetes mellitus type 2, or a history of inflammatory bowel disease. Following discharge, positron emission tomography (PET) scan showed extensive metastatic disease to multiple regional lymph nodes as well as multiple suspicious hepatic lesions and bilateral pulmonary nodules. Due to the poor prognosis, recommended treatment consisted of folinic acid, 5-fluorouracil, oxaliplatin (FOLFOX-4) along with palliative radiation.

The cause of the increase in the incidence rate of colorectal cancer in young adults remains unknown. Among this demographic, colorectal cancers appear to be more aggressive and present at later stages with more advanced disease. In young adults, the most common clinical sign at presentation is rectal bleeding. In young adults presenting with seemingly common gastrointestinal complaints, a high degree of suspicion for colorectal cancer may be warranted by clinicians.

Clinical and Molecular Comparative Study of Colorectal Cancer Based on Age-of-onset and Tumor Location: Two Main Criteria for Subclassifying Colorectal Cancer

Our aim was to characterize and validate that the location and age of onset of the tumor are both important criteria to classify colorectal cancer (CRC). We analyzed clinical and molecular characteristics of early-onset CRC (EOCRC) and late-onset CRC (LOCRC), and we compared each tumor location between both ages-of-onset. In right-sided colon tumors, early-onset cases showed extensive Lynch syndrome (LS) features, with a relatively low frequency of chromosomal instability (CIN), but a high CpG island methylation phenotype. Nevertheless, late-onset cases showed predominantly sporadic features and microsatellite instability cases due to BRAF mutations. In left colon cancers, the most reliable clinical features were the tendency to develop polyps as well as multiple primary CRC associated with the late-onset subset. Apart from the higher degree of CIN in left-sided early-onset cancers, differential copy number alterations were also observed. Differences among rectal cancers showed that early-onset rectal cancers were diagnosed at later stages, had less association with polyps, and more than half of them were associated with a familial LS component. Stratifying CRC according to both location and age-of-onset criteria is meaningful, not only because it correlates the resulting categories with certain molecular bases, but with the confirmation across larger studies, new therapeutical algorithms could be defined according to this subclassification.

Prevalence and clinicopathological characteristics of mismatch repair-deficient colorectal carcinoma in early onset cases as compared with late-onset cases: a retrospective cross-sectional study in Northeastern Iran

OBJECTIVES

Lynch syndrome (LS), a genetically inherited autosomal disorder, increases the incidence of colorectal carcinoma (CRC). We aimed to perform a universal strategy to assess the prevalence and clinicopathological characteristics of early onset CRCs at high risk of LS versus late-onset ones in the Iranian population.

SETTING

A local population-based study from Northeastern Iran.

PARTICIPANTS

321 consecutive CRCs and pathology specimen screened between 2013 and 2016.

PRIMARY AND SECONDARY OUTCOME MEASURES

Retrospectively, information regarding the clinical criteria was obtained by interviewing the patients with CRC or, their families. Pathologists tested tumours with immunohistochemistry (IHC) staining of four mismatch repair (MMR) proteins (MLH1, MSH2, MSH6 and PMS2). Tumours with absent IHC staining of MLH1 were tested for BRAF mutations to exclude sporadic CRCs. Prevalence of early onset CRCs at high risk of LS and familial CRC type X were assessed as primary and secondary outcome measures, respectively.

RESULTS

Of 321 CRCs (13/123 (10.57%), early onset vs 21/198 (10.6%) late-onset) were detected to be MMR-deficient (dMMR). Nine early onset cases and 14 late-onset ones with a loss of MLH1 underwent testing for the BRAF mutation, none of the early onset and four (2.02%) late-onset were recognised as sporadic. The difference in the outcome of IHC-analysis between early and late-onset CRCs at high risk of LS was not statistically significant (p=0.34). Majority of the suspected LS tumours from early onset patients had arisen in distal part (8/11 (72.72%) vs 8/14 (57.14%)), all of which were occurred in the rectum or sigmoid.

CONCLUSION

Clinically, these findings suggest that in case of limitation for BRAF testing, the practitioner in Iran may consider managing early onset dMMR cases like LS until access to BRAF testing becomes available to them, before germline testing to accurately diagnose LS.

Decreased expression of ARHGAP15 promotes the development of colorectal cancer through PTEN/AKT/FOXO1 axis

Copious evidence demonstrates the crucial role of Rho GTPase-activating proteins in human malignancies. The downregulation of Rho GTPase-activating protein 15 (ARHGAP15), a Rac1-specific GAP, has been observed in glioma and pancreatic ductal adenocarcinoma. The present study explored the expression in colorectal cancer (CRC) by quantitative real-time PCR and immunohistochemistry analysis. The possible function of ARHGAP15 in CRC was investegated in vitro and in vivo. We found that ARHGAP15 expression was obviously lower in CRC specimens than in normal colonic mucosa. ARHGAP15 expression was significantly correlated with clinical stage, tumor size metastasis, vital status, and overall survival of CRC patients. ARHGAP15 overexpression inhibited cell growth, migration, and invasion of HT29 and RKO cells in vitro, whereas opposite results were observed in ARHGAP15-silenced LoVo cells. Mechanically, we found that PTEN (phosphatase and tensin homology deleted on chromosome 10) signaling pathway was closely correlated with ARHGAP15 expression by Gene set enrichment analysis with The Cancer Genome Atlas CRC data set. Increased PTEN and Forkhead box protein O1 (FOXO1, a downstream transcription factor of AKT), and decreased phosphorylation of AKT were observed in ARHGAP15-overexpressed HT29 and RKO cells. In addition, ARHGAP15 overexpression increased p21, which was responsible for the accelerated cell growth and S phase arrest, but decreased the protein levels of MMP-2 and MMP-9, which were stimuli for cell metastasis. Notably, upregulating PTEN expression, FOXO1 overexpression and interdicting the activation of AKT pathway with MK2206 suppressed the proliferation and the metastatic ability of ARHGAP15-silenced LoVo cells. In addition, FOXO1 overexpression markedly enhanced the expression and the promoter activity of ARHGAP15. Furthermore, ARHGAP15 overexpression significantly decelerated the pace of tumor growth and metastasis in the lung in vivo. In summary, these results suggest that ARHGAP15 might serve as a tumor suppressor during CRC progression and metastasis through PTEN/AKT/FOXO1-signaling pathway.

Metastatic colorectal cancer during pregnancy: A tertiary center experience and review of the literature

Background

Colorectal cancer during pregnancy is rare. Diagnosis may be delayed and clinicians are faced with unique challenges when formulating management plans, having to consider the well-being of both fetus and mother.

Cases

Our series outlines five cases of metastatic colorectal cancer during pregnancy. There was one patient who presented in each of the first, second and third trimesters, whilst the remaining were post-partum. Diagnosis was difficult as the patients were either asymptomatic or their symptoms were misconstrued as features of pregnancy. Two patients received chemotherapy while pregnant but only one had a successful delivery. Survival of patients in this series ranged between 1 and 35 months from diagnosis.

Conclusion

Women with gestational colorectal cancer are often diagnosed at an advanced stage and have a poor prognosis.

Colorectal cancer incidence and clinicopathological features in northern Tunisia 2007–2009

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. The aim of this study was to determine CRC incidence and to describe clinicopathological features in north Tunisia for the period 2007–2009. The North Tunisia Cancer Registry was the source of data for the identification of patients. The age-standardized incidence rates (ASRs) were respectively 13.6 cases (7.5/100,000 for colon cancer and 6.2 for rectal cancer) and 11.1 cases (6.5/100,000 for colon cancer and 4.4 for rectal cancer) per 100,000 among male and female. The ASR varied widely by regions in northern Tunisia.  The most common site in colon cancer was the distal colon comparing to the proximal one (49.0 and 29.9% respectively). Adenocarcinoma was the most common histological type. CRC screening should be strengthened in Tunisia to achieve a reduction of CRC incidence and mortality.