Colorectal Cancer Mortality Research Articles

Abstract 7004: DNA Methylation analysis of African American colorectal cancers reveal race-specific alterations

Abstract African Americans (AAs) have among the highest incidence and mortality rates of colorectal cancer (CRC) in the US. They present with more right-sided, microsatellite stable (MSS) tumors and are diagnosed at earlier ages than non-Hispanic Whites (NHW). While DNA methylation changes and their significance have been previously described in CRC, much less is known about the unique DNA methylation changes that occur in AA CRCs compared to NHW CRCs. In the current study, we analyzed DNA methylation changes in AA patients and compared those changes to data from NHWs. AA patients diagnosed with a MSS colorectal tumor at the Yale New Health System were included in the study. A pathologist reviewed archival slides, and selected areas from CRCs (n=160) and adjacent normal tissue (n=42) were cored (median age=59; 82 females, 78 males). DNA was bisulfite converted and analysis performed using EPIC arrays. The 450K methylation array from NHW CRCs was also analyzed for 217 CRCs and 20 normal tissues obtained from TCGA (median age=68; 103 females, 114 males). Differentially methylated regions (DMRs) with |Δβ|>0.1, FDR corrected p-value <0.05 between tumor and normal tissue were identified using SeSAMe. We identified 4881 DMRs (57% hyper- and 44% hypomethylated) between AA CRC and normal tissue. Of these, 46% were in CpG Islands, 15% in CpG Shores, 4% in CpG shelves, and 36% in open sea. Most DMRs (71%) were in promoter regions, with 18% in gene bodies, 5% in enhancer regions, and 6% in intergenic regions. Next, we performed additional DMR analysis using overlapping probes from both arrays to compare NHW with AA data. We identified 2239 DMRs between AA CRC and normal tissue compared to 4138 in NHW. Of the 2239 AA DMRs, 1419 (66%) were common with NHW DMRs, 790 (34%) were unique to AAs. There were many overlapping pathways and genes; however, the DMRs impacting these pathways differed between AA and NHW CRCs. Hypermethylation of LCK, a tyrosine kinase involved in T-cell receptor signaling, was found in 60% of AA CRCs compared to 5.9% of NHW CRCs. LCK hypermethylation leads to CD4/8 T-cell inactivation and linked to poor outcomes in lung cancer. We observed AA-specific hypermethylation of SSTR1 in 57.2% of AA CRCs compared to 27.6% of NHW CRCs. Somatostasin (SST) suppresses tumor growth by regulating certain factors involved in cell proliferation. Hypermethylation of SSTR1 has been associated with various malignancies including gastric cancer. Lastly, promoter hypermethylation of 3 protocadherin genes was found in 65.1% of AAs compared to 33.1% NHWs. Protocadherins regulate WNT signaling and hypermethylation is associated with poor outcomes in multiple cancers. Taken together, these results show AA-specific CRC methylation changes compared with NHW CRCs. Further work is warranted to investigate the potential functional and clinical implications of these methylation alterations, some of which may represent therapeutic targets and biomarkers. Citation Format: Seeta Rajpara, David N. Buckley, Rosa Xicola, Reger Mikaeel, Mary K. Yagle, Baris Kerimoglu, Curtis Thorne, Dante A. Bellomo, Megha Padi, Xavier Llor, Nathan Ellis, Bodour Salhia. DNA Methylation analysis of African American colorectal cancers reveal race-specific alterations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7004.

Abstract 1168: Anti-CSF1R antibody monotherapy inhibits minimal residual disease in a novel immunocompetent murine colorectal cancer metastasis model

Abstract Background: The high mortality rate of colorectal cancer (CRC) is primarily due to metastatic disease. Microscopic minimal residual disease (MRD) detected in patients by circulating tumor DNA (ctDNA) may remain radiographically undetectable and persist following therapeutic intervention, resulting in recurrence. Preclinical models are urgently needed to elucidate the mechanisms whereby MRD escapes anti-tumor immune surveillance. We have developed and characterized a preclinical liver MRD model that recapitulates immune response, with the goal to discover novel strategies to improve outcomes for patients with ctDNA+ MRD. Methods: We generated genetically engineered mouse colonic organoids CDX2 CRE; Rosa26 LSL-CAS9-GFP with APC and TP53 mutation and performed intrasplenic injection in syngeneic C57BL/6 mice to recapitulate microsatellite stable CRC metastasis to the liver. Mice were monitored for radiographically detectable disease using MRI. Tumors were resected at various timepoints, with comparison between metastases at various sizes of development (dichotomized as micro- and macro-metastases). We performed multiplex immunofluorescence staining, single cell RNA seq, and spatial transcriptomic analysis to delineate the immune compartments of micro- and macro-metastasis in untreated mice. After identifying colony stimulating factor -1 receptor (CSF1R) as a target, we performed a vehicle controlled anti-CSF1R monotherapy study for 4 weeks. Treatment began at either 7 days before metastasis is radiographically detectable to mimic treatment of MRD, or 21 days post tumor engraftment. Results: Immune exclusion was confirmed through intratumoral CD45+ leukocyte densities, with transition to an immune excluded phenotype occurring above 0.5mm in size (defined as macro-metastases). In our preclinical model, immunosuppressive populations of macrophages (IBA1+CD163+) dominated in the micro-metastases. This observation was confirmed in 13 patients with paired micro- and macro-metastases to the liver (p=0.0065). Strikingly, anti-CSF1R treatment in the murine model eradicated IBA1+CD163+ macrophages (p<0.0001) and induced complete remission of liver micro-metastasis (0/7 mice with residual disease), in contrast to limited efficacy for macro-metastases (5/5 mice with progressed radiographically disease). Additionally, a long-term study confirmed 100% survival (5/5 mice) and no evidence of disease via MRI at 6 months upon anti-CSF1R treatment compared to vehicle (0/5 mice). Conclusions: We established a reproducible preclinical model of MRD with similar immunopathological features of MRD in patients. Our data further identified infiltration of immunosuppressive macrophage populations as an early determinant of MRD progression and indicated CSF1R as a potential new clinical therapeutic target for ctDNA+-defined MRD patients. Citation Format: Alaa M. Mohamed, Kyung Serk Cho, Melinda Soeung, Amanda Anderson, Jumanah Alshenaifi, Ganiraju Manyam, Oscar Villareal, Jennifer Davis, Will Norton, Sisi Gao, Christopher Bristow, Federica Carbone, Stefania Napolitano, Oluwadara Coker, Isha Khanduri, Justin Huang, Dipen M. Maru, Mauro Di Pilato, Ryan Sun, Linghua Wang, David G. Menter, Giannicola Genovese, Giulio Draetta, Natalie Fowlkes, Scott Kopetz. Anti-CSF1R antibody monotherapy inhibits minimal residual disease in a novel immunocompetent murine colorectal cancer metastasis model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1168.

Abstract 6180: Tumor microenvironment phenotypes predict recurrence in African Americans diagnosed with colorectal cancer: A comparative study of manual grading with digital pathology

Abstract African Americans face a higher rate of colorectal cancer (CRC) incidence and mortality compared to other ethnicities. Identifying key prognostic factors is essential for better outcomes in this group. This study focused on the prognostic value of stromal grading in the tumor microenvironment (TME) of African American CRC patients, using both manual grading and digital pathology. A retrospective analysis of CRC cases in African Americans was conducted. Two cohorts were established: a control cohort (patients without recurrence) and a recurrence cohort (patients with recurrence). Stromal grading was performed manually, categorizing tumors into Grade 1 (low risk), Grade 2 (moderate risk), and Grade 3 (high risk), and we also quantified the TME percentages by digital pathology: myxoid, collagen, immune and tumor. In the control cohort (N=40), stromal grading identified 30 Grade 1, 7 Grade 2, and 3 Grade 3 cases. Conversely, the recurrence cohort (N=17) demonstrated a starkly different distribution, with 1 Grade 1, 3 Grade 2, and 13 Grade 3 cases. The Chi-square statistic was notably significant (p<0.0001), indicating a strong association between higher stromal grades and the likelihood of recurrence. By unpaired t-test, high myxoid stroma (p<0.0001), low collagen (p<0.0001), and low tumor (p=0.0002) by digital pathology were associated with recurrence. TME phenotypes are a significant prognostic and recurrence indicator in African American patients with CRC. The marked difference in stromal grades and digital pathology features between the control and recurrence cohorts suggests that higher stromal grades, along with higher myxoid, lower collagen and lower tumor percentages are associated with an increased risk of recurrence. These findings underscore the need for tailored therapeutic strategies and more vigilant surveillance in African American patients exhibiting high-risk TME phenotypes. The efficacy of manual and digital pathology evaluation of the TME also warrants further exploration to enhance prognostic accuracy and treatment personalization. Citation Format: Dongling Wu, Rong Xia, Mouyed Alawad, Lili Lee, Tamas Gonda, Wenqing Cao, Sean Hacking. Tumor microenvironment phenotypes predict recurrence in African Americans diagnosed with colorectal cancer: A comparative study of manual grading with digital pathology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6180.

Abstract 250: Sex differences in cancer stemness among individuals with early onset colorectal cancer

Abstract Since 1990, the overall incidence and mortality rates of late onset colorectal cancer (LOCRC ≥50 years) have been decreasing due to improvements in access to screening and available treatment options. However, the rates for early onset CRC (EOCRC ≤ 49 years) have steadily increased in men and women. Less than 30% of LOCRC patients present with late-stage tumors (clinical stages III or IV) at the time of diagnosis compared to 70% of EOCRC patients. Despite this, the cellular and molecular mechanisms underlying the incidence and stage are unclear, as are appropriate strategies for prevention of recurrence in men and women with EOCRC. Effective prognostic markers are therefore urgently needed. To address this issue, we performed a detailed bioinformatics analysis based on Gene Expression Omnibus database (GSE39582; n=585 patients), wherein we identified 7 prognostic biomarkers for EOCRC: KRAS, LGR5, CTNNB1, MYC, BMI1, CD44 and ASNS. Importantly, Kaplan Meier analysis revealed tumor onset at a younger age was significantly (p = 0.0082) associated with poorer 5-year survival in men with EOCRC only, after adjusting for KRAS status. CTNBB1 and CD44 transcript levels were higher in men with EOCRC versus men with LOCRC. Conversely, female EOCRC had a higher frequency of KRAS mutations (52.6%) compared to their LOCRC counterpart (38.8%), and an increased expression of markers of tumor stem cell and metabolic reprogramming including LGR5, MYC, BMI, and ASNS. A single CRISPR-Cas9 deletion of ASNS in HCT116 cell lines, a pre-clinical model of EOCRC, caused an inhibition of 3D spheroid formation compared to HCT116 ASNS wild type cells. In vivo study using a cell line derived R2G2 mouse xenograft model showed that ASNS disruption caused a reduction in tumor burden that was accompanied by low Lgr5 and Myc transcripts compared to the ASNS wild type group, indicating that ASNS may regulate cancer stemness. Together, this data suggests a unique molecular fingerprint for EOCRC and highlights sex-specific influences on cellular metabolism during EOCRC progression. Citation Format: Oladimeji Aladelokun, Kaelyn Sumigray, Sajid A. Khan, Caroline Johnson. Sex differences in cancer stemness among individuals with early onset colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 250.

Abstract 6135: Racial and ethnic differences in site of de novo metastases in patients with colorectal cancer: A SEER analysis

Abstract Purpose: Disparities in colorectal cancer (CRC) mortality may be driven by differences in access to care, tumor biology, and propensity to spread to distant sites. We examine differences in patterns of de novo metastases by race/ethnicity and age. Methods: We identified 248,732 CRC patients listed in the Surveillance, Epidemiology, and End Results (SEER) database diagnosed with a first primary invasive CRC from 2010-2020, aged 20+ years at diagnosis, with complete data on SEER summary stage, and not diagnosed only by autopsy/death certificate. Outcomes included de novo metastatic site (no metastasis, liver, lung, brain, bone) and pattern (no metastasis, liver only, lung only, liver and lung, other). We used logistic regression to calculate odds ratios (OR) and 95% confidence intervals (95% CI) for the associations between 1) demographic and tumor characteristics (site, side, T stage, N stage) and site of de novo metastases , and 2) race/ethnicity and site of de novo metastases stratified by age (20-49, 50-74, 75+). We used multinomial logistic regression to assess the association between demographic and tumor characteristics and pattern of metastasis. Models adjusted for age, race/ethnicity, sex, site (colon, rectum), side (left, right), T stage, and N stage. Results: 62,844 stage IV CRC cases were diagnosed from 2010-2020, and liver was the most common metastatic site (72%). Relative to age 50-74, age 20-49 at diagnosis was more strongly associated with de novo liver metastases (OR: 1.07; 95% CI: 1.02-1.11) and less with lung (OR: 0.86; 95% CI: 0.80-0.92) or brain (OR: 0.69; 95% CI: 0.52-0.93) metastases. Relative to Non-Hispanic White (NHW) patients, Non-Hispanic American Indian/Alaskan Native (AI/AN) patients had a higher risk of lung metastases (OR: 1.33; 95% CI: 1.07-1.65), Non-Hispanic Asian/Pacific Islander (API) patients had lower risks of liver (OR: 0.87; 95% CI: 0.83-0.92) and brain (OR: 0.67; 95% CI: 0.48-0.95) metastases, and Non-Hispanic Black (NHB) patients had higher risks of liver (OR: 1.35; 95% CI: 1.29-1.41), lung (OR: 1.36; 95% CI: 1.27-1.45), and bone (OR: 1.23; 95% CI: 1.08-1.41) metastases. In age-stratified analyses, the risks for NHB patients persisted across groups, while lower risks for API patients were not observed in the 20-49 group. API patients aged 20-49 had a higher risk of de novo lung (OR: 1.31; 95% CI: 1.06-1.61) and bone (OR: 1.63; 95% CI: 1.13-2.37) metastases, and the increased risk of lung metastases for AI/AN patients was larger in magnitude (OR: 2.26; 95% CI: 1.39-3.68). Age 20-49 was more strongly associated with a liver-only pattern (OR: 1.14; 95% CI: 1.09-1.19) and with less common distant sites (OR: 1.33; 95% CI: 1.25-1.41). Conclusions: Racial/ethnic differences in de novo metastatic CRC patterns exist overall and across age groups. These findings are consistent with disparities in risk of stage IV CRC and can inform surveillance priorities in CRC survivors. Citation Format: Nicole C. Loroña, Mariana C. Stern, Stephanie L. Schmit, Jane C. Figueiredo. Racial and ethnic differences in site of de novo metastases in patients with colorectal cancer: A SEER analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6135.

Abstract 3453: U.S. Geographic and socio-demographic characteristics of Voyage Study participants

Abstract The Voyage Study is a large-scale, prospective cohort study of long-term health outcomes among participants with a valid multi-target stool DNA (mt-sDNA) test order. Recently, the Voyage Study achieved its enrollment target of 150,000 participants. The intent of this descriptive analysis is to provide baseline geographic and socio-demographic characteristics of Voyage Study participants to set the stage for future comparisons to the broader mt-sDNA user population. Participants were randomly selected from all persons in the U.S. or Puerto Rico who had a valid order for mt-sDNA screening during the enrollment period (10/18/2019 - 10/17/2023). Enrolled participants completed a baseline questionnaire that collected socio-demographic and health information. Participant characteristics and baseline survey answers were compared between regions using chi-square tests where appropriate. Regional geographic data was aggregated for the broader mt-sDNA user population during the enrollment period, though no formal comparisons were made between the broader population and the Voyage population at this time. Analyses were limited to 139,369 participants with available baseline questionnaire data. Voyage participants were more likely to reside in the Midwest, Northeast, or Southeast (29.9%, 22.5%, 22.6% respectively) and less likely to reside in the Southwest and West (11.6%, 13.4%). During the enrollment period, differential participation was also observed in the mt-sDNA user population, with the Midwest, Northeast, and Southeast having the greatest proportion (25.4%, 22.2%, 26.7%) and the Southwest and West having the lowest proportion of mt-sDNA users (13.8%, 11.9%). In the Voyage cohort, Midwest participants reported the lowest education attainment as characterized by years of school completed (14.1% high school or below, 59.2% college or greater), while participants in the West reported the highest education attainment (7.9% high school or below, 67.3% college or greater). The West also had the highest percentage of participants reporting an income of $100,000 or greater (51.6%), with the Southeast being the lowest (42.2%), as compared to the other regions. We report here early results of geographic and socio-demographic characteristics from a new research resource that will enable future analyses of health outcomes and behaviors in a population of mt-sDNA users. We observed that the greatest percentage of Voyage participants resided in the Midwest, Northeast, or Southeast, and that there was differential socio-demographic participant characteristics based on region. Future analyses will compare long-term healthcare outcomes and differences in colorectal cancer incidence and mortality between the broader mt-sDNA user population and the Voyage cohort. Citation Format: Allison M. Berry, Jessica A. Grimm, Christine R. Kirt, Emily J. Kirsch, Rachel E. Dixon, Winnie Z. Fan, Kandace A. Bohn, Jennifer St. Sauver, Kathleen J. Yost, Lila J. Finney Rutten, Janet E. Olson. U.S. Geographic and socio-demographic characteristics of Voyage Study participants [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3453.

Social Determinants of Health and the Link to Colorectal Cancer Outcomes.

OPINION STATEMENT: Colorectal cancer (CRC) remains the second most deadly cancer in the United States, behind only lung cancer. Despite improvements in incidence due to screening and mortality in part due to better treatments, there are some groups that have not seen these promising changes. American Indian/Alaska Native and non-Hispanic Black individuals, certain geographic regions, and lower socioeconomic groups have all been shown to have worse CRC outcomes. A significant body of evidence has linked these disparities in outcomes to social determinants of health (SDH). SDH are defined by the WHO as "the non-medical factors that influence health outcomes." These factors include but are not limited to income, education, social support, neighborhood of residence, and access to healthcare. Individuals who are negatively impacted by SDH have been shown to have a higher incidence of CRC. These individuals are also less likely to receive adequate CRC screening, are less likely to receive appropriate treatment, and have increased CRC mortality. Interventions that target different SDH domains have been shown to lead to increased rates of CRC screening and receipt of appropriate treatment while simultaneously improving CRC mortality. The aim of this review is to highlight the connection between SDH and CRC outcomes while also exploring interventions that target SDH and thereby improve CRC outcomes.

Expression and significance of pigment epithelium-derived factor and vascular endothelial growth factor in colorectal adenoma and cancer.

The incidence and mortality of colorectal cancer (CRC) are among the highest in the world, and its occurrence and development are closely related to tumor neovascularization. When the balance between pigment epithelium-derived factors (PEDF) that inhibit angiogenesis and vascular endothelial growth factors (VEGF) that stimulate angiogenesis is broken, angiogenesis is out of control, resulting in tumor development. Therefore, it is very necessary to find more therapeutic targets for CRC for early intervention and later treatment. To investigate the expression and significance of PEDF, VEGF, and CD31-stained microvessel density values (CD31-MVD) in normal colorectal mucosa, adenoma, and CRC. In this case-control study, we collected archived wax blocks of specimens from the Digestive Endoscopy Center and the General Surgery Department of Chengdu Second People's Hospital from April 2022 to October 2022. Fifty cases of specimen wax blocks were selected as normal intestinal mucosa confirmed by electronic colonoscopy and concurrent biopsy (normal control group), 50 cases of specimen wax blocks were selected as colorectal adenoma confirmed by electronic colonoscopy and pathological biopsy (adenoma group), and 50 cases of specimen wax blocks were selected as CRC confirmed by postoperative pathological biopsy after inpatient operation of general surgery (CRC group). An immunohistochemical staining experiment was carried out to detect PEDF and VEGF expression in three groups of specimens, analyze their differences, study the relationship between the two and clinicopathological factors in CRC group, record CD31-MVD in the three groups, and analyze the correlation of PEDF, VEGF, and CD31-MVD in the colorectal adenoma group and the CRC group. The F test or adjusted F test is used to analyze measurement data statistically. Kruskal-Wallis rank sum test was used between groups for ranked data. The chi-square test, adjusted chi-square test, or Fisher's exact test were used to compare the rates between groups. All differences between groups were compared using the Bonferroni method for multiple comparisons. Spearman correlation analysis was used to test the correlation of the data. The test level (α) was 0.05, and a two-sided P< 0.05 was considered statistically significant. The positive expression rate and expression intensity of PEDF were gradually decreased in the normal control group, adenoma group, and CRC group (100% vs 78% vs 50%, χ2 = 34.430, P < 0.001; ++~++ vs +~++ vs -~+, H = 94.059, P < 0.001), while VEGF increased gradually (0% vs 68% vs 96%, χ2 = 98.35, P < 0.001; - vs -~+ vs ++~+++, H = 107.734, P < 0.001). In the CRC group, the positive expression rate of PEDF decreased with the increase of differentiation degree, invasion depth, lymph node metastasis, distant metastasis, and TNM stage (χ2 = 20.513, 4.160, 5.128, 6.349, 5.128, P < 0.05); the high expression rate of VEGF was the opposite (χ2 = 10.317, 13.134, 17.643, 21.844, 17.643, P < 0.05). In the colorectal adenoma group, the expression intensity of PEDF correlated negatively with CD31-MVD (r = -0.601, P < 0.001), whereas VEGF was not significantly different (r = 0.258, P = 0.07). In the CRC group, the expression intensity of PEDF correlated negatively with the expression intensity of CD31-MVD and VEGF (r = -0.297, P < 0.05; r = -0.548, P < 0.05), while VEGF expression intensity was positively related to CD31-MVD (r = 0.421, P = 0.002). It is possible that PEDF can be used as a new treatment and prevention target for CRC by upregulating the expression of PEDF while inhibiting the expression of VEGF.

A case–control study of the association between the gut microbiota and colorectal cancer: exploring the roles of diet, stress, and race

BackgroundThe gut microbiota is associated with risk for colorectal cancer (CRC), a chronic disease for which racial disparities persist with Black Americans having a higher risk of CRC incidence and mortality compared to other groups. Given documented racial differences, the gut microbiota may offer some insight into previously unexplained racial disparities in CRC incidence and mortality. A case–control analysis comparing 11 women newly diagnosed with CRC with 22 cancer-free women matched on age, BMI, and race in a 1:2 ratio was conducted. Information about participants’ diet and perceived stress levels were obtained via 24-h Dietary Recall and Perceived Stress Scale-10 survey, respectively. Participants provided stool samples from which microbial genomic DNA was extracted to reveal the abundance of 26 genera chosen a priori based on their previously observed relevance to CRC, anxiety symptoms, and diet.ResultsSignificantly lower alpha diversity was observed among cancer-free Black women compared to all other race-cancer status combinations. No group differences were observed when comparing beta diversity. Non-Hispanic White CRC cases tended to have higher relative abundance of Fusobacteria, Gemellaceae, and Peptostreptococcus compared to all other race-cancer combination groups. Perceived stress was inversely associated with alpha diversity and was associated with additional genera.ConclusionsOur findings suggest that microbiome-CRC associations may differ by racial group. Additional large, racially diverse population-based studies are needed to determine if previously identified associations between characteristics of the gut microbiome and CRC are generalizable to Black women and other racial, ethnic, and gender groups.

Screening Implications for Distribution of Colorectal Cancer Subsite by Age and Role of Flexible Sigmoidoscopy.

Objectives: The effectiveness of colonoscopy to reduce colorectal cancer (CRC) mortality is extrapolated from cohort studies in the absence of randomized controlled trial (RCT) data, whereas flexible sigmoidoscopy is supported by RCT data and may be easier to implement in practice. We characterized the anatomic distribution of CRC to determine the proportion that is visible with sigmoidoscopy. Methods: Patients with a primary diagnosis of colorectal adenocarcinoma were identified in the Surveillance, Epidemiology, and End Results program (2000-2020). Tumors from the rectum to the descending colon were categorized as visible by sigmoidoscopy, whereas more proximal tumors required colonoscopy. Differential prognosis between tumor locations, stratified by age groups and stage, was assessed using the overall restricted mean survival time (RMST) at 2, 5, and 10 years. Results: Among 309,466 patients, 58% had tumors visible by sigmoidoscopy, including 73% of those under age 50 (OR 2.10, 95% CI 2.03-2.16 age < 45, OR 2.20, 95% CI 2.13-2.27 age 45-49 versus age ≥ 50). Male sex (OR 1.54, 95% CI 1.51-1.56) and Asian or Pacific Islander race (OR 1.60, 95% CI 1.56-1.64) were also positively associated with tumors visualizable by sigmoidoscopy. Across age groups, for local disease, RMST was comparable for tumors visible versus not visible on sigmoidoscopy. For regional and metastatic cancer, patients with tumors visible by sigmoidoscopy had improved RMST versus those with more proximal tumors. Conclusions: 58% of CRC arises in locations visible by flexible sigmoidoscopy. Flexible sigmoidoscopy should be considered as a viable option for CRC screening, particularly in younger patients unwilling or unable to undergo colonoscopy.

Contributions of early detection and cancer prevention to colorectal cancer mortality reduction by screening colonoscopy: a validated modeling study

Background and aimsScreening colonoscopy, recommended every ten years, reduces mortality from colorectal cancer (CRC) by early detection of prevalent but undiagnosed CRC, as well as by prevention of CRC by removal of precursor lesions. The aim of this study was to assess the relative contribution of both components to total CRC mortality reduction over time. MethodsUsing a validated multistate Markov model, we simulated hypothetical cohorts of 100,000 individuals aged 55-64 with and without use of screening at baseline. Main outcomes included proportions of prevented CRC deaths arising from (asymptomatic) CRC already prevalent at baseline and from newly developed CRC during 15-years of follow-up, and mortality rate ratios of screened versus unscreened groups over time. ResultsEarly detection of prevalent cases accounted for 52%, 30% and 18% of deaths prevented by screening colonoscopy within 5, 10 and 15 years, respectively. Relative reduction of mortality was estimated to be much larger for mortality from incident cancers than for mortality from cancers that were already present and early detected at screening endoscopy and for total CRC mortality (i.e., 88% versus 67% and 79% within 10 years from screening). ConclusionsReduction of CRC mortality mainly arises from early detection of prevalent cancers during the early years after screening colonoscopy, but prevention of incident cases accounts for the majority of prevented deaths in the longer run. Prevention of incident cases leads to sustained strong reduction of colorectal cancer mortality, possibly warranting an extension of screening intervals.

Carbohydrate quality, not quantity, linked to reduced colorectal cancer incidence and mortality in US populations: evidence from a prospective study

BackgroundCarbohydrates have been implicated in colorectal cancer (CRC) risk, but the specific impact of carbohydrate quality and quantity on CRC susceptibility in US populations remains unclear.MethodsWe followed 101,694 participants from Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. The carbohydrate quality index (CQI) and low-carbohydrate diet score (LCDs) were used to evaluate the daily carbohydrate quality and quantity separately, where higher scores indicated greater adherence. Cox proportional hazards regression was used to compute HRs and 95% CIs for incident CRC and related death. Subgroup analyses were conducted to identify potential effect modifiers.ResultsDuring follow-up, we documented 1085 incident cases of CRC, of whom 311 died from CRC. Individuals in the highest compared with the lowest quartiles of CQI had a lower CRC incidence (Q4 vs Q1: HR 0.80, 95% CI 0.67–0.96, Ptrend = 0.012) and mortality (Q4 vs Q1: HR 0.61, 95% CI 0.44–0.86, Ptrend = 0.004). The inverse association between CQI and CRC risk was observed for distal colon and rectum but not for proximal colon cancer. Regarding mortality, this association was only significant for rectum cancer. Subgroup analyses indicated this inverse association of CQI with CRC risk was only observed in participants with lower LCDs. No significant associations were found between LCDs and CRC incidence or mortality.ConclusionsOur findings suggest focusing on higher quality, rather than restricting the quantity, of carbohydrate consumption may be an effective approach to reduce the risk of CRC in the US population, particularly for distal colon and rectal cancers.

Recent Advances in Therapeutic Strategies to Improve Colorectal Cancer Treatment.

Colorectal cancer (CRC) is the second-leading cause of cancer-related mortality worldwide. CRC mortality results almost exclusively from metastatic disease (mCRC) for which systemic chemotherapy is often a preferred therapeutic option. Biomarker-based stratification of mCRC enables the use of precision therapy based on individual tumor mutational profiles. Activating mutations in the RAS/RAF/MAPK pathway downstream of EGFR signaling have, until recently, limited the use of EGFR-targeted therapies for mCRC; however, the development of anti-RAS and anti-RAF therapies together with improved strategies to limit compensatory signaling pathways is resulting in improved survival rates in several highly lethal mCRC sub-types (e.g., BRAF-mutant). The use of fluoropyrimidine (FP)-based chemotherapy regimens to treat mCRC continues to evolve contributing to improved long-term survival. Future advances in chemotherapy for mCRC will need to position development relative to the advances made in precision oncology.

Forecasting Survival Rates in Metastatic Colorectal Cancer Patients Undergoing Bevacizumab-Based Chemotherapy: A Machine Learning Approach

Background: Antibiotics can play a pivotal role in the treatment of colorectal cancer (CRC) at various stages of the disease, both directly and indirectly. Identifying novel patterns of antibiotic effects or responses in CRC within extensive medical data poses a significant challenge that can be addressed through algorithmic approaches. Machine Learning (ML) emerges as a promising solution for predicting clinical outcomes using clinical and heterogeneous cancer data. In the pursuit of our objective, we employed ML techniques for predicting CRC mortality and antibiotic influence. Methods: We utilized a dataset to examine the accuracy of death prediction in metastatic colorectal cancer. In addition, we analyzed the association between antibiotic exposure and mortality in metastatic colorectal cancer. The dataset comprised 147 patients, nineteen independent variables, and one dependent variable. Our analysis involved testing different classification-supervised ML, including an oversampling pool for classification models, Logistic Regression, Decision Trees, Naive Bayes, Support Vector Machine, Random Forest, XGBboost Classifier, a consensus of all models, and a consensus of top models (meta models). Results: The consensus of the top models’ classifier exhibited the highest accuracy among the algorithms tested (93%). This model met the standards for good accuracy, surpassing the 90% threshold considered useful in ML applications. Consistent with the accuracy results, other metrics are also good, including precision (0.96), recall (0.93), F-Beta (0.94), and AUC (0.93). Hazard ratio analysis suggests that there is no discernible difference between patients who received antibiotics and those who did not. Conclusions: Our modelling approach provides an alternative for analyzing and predicting the relationship between antibiotics and mortality in metastatic colorectal cancer patients treated with bevacizumab, complementing classic statistical methods. This methodology lays the groundwork for future use of datasets in cancer treatment research and highlights the advantages of meta models.

Impact of Helicobacter pylori Infection and Treatment on Colorectal Cancer in a Large, Nationwide Cohort.

Helicobacter pylori is the most common cause of infection-associated cancer worldwide. We aimed to evaluate the impact of H. pylori infection and treatment on colorectal cancer (CRC) incidence and mortality. US Veterans who completed H. pylori testing between 1999 and 2018. We conducted a retrospective cohort analysis among adults within the Veterans Health Administration who completed testing for H. pylori. The primary exposures were (1) H. pylori test result (positive/negative) and (2) H. pylori treatment (untreated/treated) among H. pylori-positive individuals. The primary outcomes were CRC incidence and mortality. Follow-up started at the first H. pylori testing and continued until the earliest of incident or fatal CRC, non-CRC death, or December 31, 2019. Among 812,736 individuals tested for H. pylori, 205,178 (25.2%) tested positive. Being H. pylori-positive versus H. pylori-negative was associated with higher CRC incidence and mortality. H. pylori treatment versus no treatment was associated with lower CRC incidence and mortality (absolute risk reduction 0.23%-0.35%) through 15-year follow-up. Being H. pylori-positive versus H. pylori-negative was associated with an 18% (adjusted hazard ratio [adjusted HR], 1.18 [95% CI, 1.12 to 1.24]) and 12% (adjusted HR, 1.12 [95% CI, 1.03 to 1.21]) higher incident and fatal CRC risk, respectively. Individuals with untreated versus treated H. pylori infection had 23% (adjusted HR, 1.23 [95% CI, 1.13 to 1.34]) and 40% (adjusted HR, 1.40 [95% CI, 1.24 to 1.58]) higher incident and fatal CRC risk, respectively. The results were more pronounced in the analysis restricted to individuals with nonserologic testing. H. pylori positivity may be associated with small but statistically significant higher CRC incidence and mortality; untreated individuals, especially those with confirmed active infection, appear to be most at risk.

Temporal trends in colorectal cancer mortality rates (1999-2022) in the United States.

Colorectal cancer (CRC) ranks as the third leading cause of cancer-related deaths in the United States (U.S.). Our study aims to analyze CRC mortality patterns in the U.S., focusing on gender and age groups from 1999 to 2022. We analyzed Age-Adjusted Mortality Rates (AAMRs) for CRC-related deaths using the CDC Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) database and assessed differences between age and sex. CRC-related mortality decreased significantly from 1999 to 2011 (-2.81% APC) and from 2011 to 2020 (-1.95% APC) but a not significant uptrend from 2020 to 2022 (2% APC). Males experienced a more significant decrease. Among age groups, crude mortality decreased until 2020, except in age group 45-54, which showed an annual increase in mortality of 0.9% from 2004 to 2022. Furthermore, individuals aged 75-84 and 85+ saw a nonsignificant annual increase of 1.8% and 4.5% from 2020 to 2022, respectively. Our study highlights a significant decline in age and gender-specific CRC-related mortality from 1999 to 2020. However, the worrisome uptrend observed in the younger age group of 45-54 emphasizes the importance of implementing targeted public health measures and evidence-based interventions.

Engaging with Rural Communities for Colorectal Cancer Screening Outreach Using Modified Boot Camp Translation

Abstract: Background: Colorectal cancer (CRC) incidence and mortality are disproportionately high among rural residents and Medicaid enrollees. Objectives: To address disparities, we used a modified community engagement approach, Boot Camp Translation (BCT). Research partners, an advisory board, and the rural community informed messaging about CRC outreach and a mailed fecal immunochemical test program. Methods: Eligible rural patients (English-speaking and ages 50–74) and clinic staff involved in patient outreach participated in a BCT conducted virtually over two months. We applied qualitative analysis to BCT transcripts and field notes. Results: Key themes included: the importance of directly communicating about the seriousness of cancer, leveraging close clinic-patient relationships, and communicating the test safety, ease, and low cost. Conclusions: Using a modified version of BCT delivered in a virtual format, we were able to successfully capture community input to adapt a CRC outreach program for use in rural settings. Program materials will be tested during a pragmatic trial to address rural CRC screening disparities.

The risk of colorectal cancer incidence in a cohort of individuals occupationally exposed to ionizing radiation

The increased risk of colorectal cancer following ionizing radiation exposure was demonstrated in a number of epidemiological studies. Earlier, no impact of occupational radiation exposure on colorectal cancer incidence or mortality was observed in a cohort of workers of the nuclear industrial facility, Mayak Production Association (PA). Extension of the follow-up of the cohort and improvement of dose estimates for personnel made it possible to update the earlier findings. The study objective is to assess the risk of colorectal cancer incidence associated with chronic occupational radiation exposure taking into account non-radiation factor effects. The study cohort included 22,377 workers employed at the reactor, plutonium-producing and radiochemical plants of Mayak PA (hiring period 1948–1982; follow-up period ended on December 31, 2018). Using the Poisson regression (EPICURE software), the relative risks (RRs with 95 % confidence intervals, (95 % CI)) of colorectal cancer incidence were estimated depending on the most significant non-radiation factors (sex, age, smoking, alcohol consumption, excessive body mass and obesity, intestinal polyps, chronic colitis). These values were also calculated for certain ranges of occupational exposure doses relying on data provided by ‘The Mayak Worker Dosimetry System – 2013’. The linear model was used to analyze the dose-response relationship. In the study cohort, the RR of colorectal cancer incidence was lower in females than in males: 0.72 (95 % CI: 0.55; 0.96) for colon and 0.48 (95 % CI: 0.34; 0.67) for rectum. The increased RR of the rectum cancer incidence was observed for cases with intestinal polyps: 3.42 (95 % CI: 1.68; 6.19). The colon cancer incidence risk increased with increasing age of workers, but other non-radiation factors were not shown to affect the results. This study supported the earlier results: no association was observed between the risk of colorectal cancer incidence and doses of occupational external gamma-ray or internal alpha-particle exposures.

Риск заболеваемости раком кишечника в когорте работников, подвергшихся хроническому профессиональному облучению

The increased risk of colorectal cancer following ionizing radiation exposure was demonstrated in a number of epidemiological studies. Earlier, no impact of occupational radiation exposure on colorectal cancer incidence or mortality was observed in a cohort of workers of the nuclear industrial facility, Mayak Production Association (PA). Extension of the follow-up of the cohort and improvement of dose estimates for personnel made it possible to update the earlier findings. The study objective is to assess the risk of colorectal cancer incidence associated with chronic occupational radiation exposure taking into account non-radiation factor effects. The study cohort included 22,377 workers employed at the reactor, plutonium-producing and radiochemical plants of Mayak PA (hiring period 1948–1982; follow-up period ended on December 31, 2018). Using the Poisson regression (EPICURE software), the relative risks (RRs with 95 % confidence intervals, (95 % CI)) of colorectal cancer incidence were estimated depending on the most significant non-radiation factors (sex, age, smoking, alcohol consumption, excessive body mass and obesity, intestinal polyps, chronic colitis). These values were also calculated for certain ranges of occupational exposure doses relying on data provided by ‘The Mayak Worker Dosimetry System – 2013’. The linear model was used to analyze the dose-response relationship. In the study cohort, the RR of colorectal cancer incidence was lower in females than in males: 0.72 (95 % CI: 0.55; 0.96) for colon and 0.48 (95 % CI: 0.34; 0.67) for rectum. The increased RR of the rectum cancer incidence was observed for cases with intestinal polyps: 3.42 (95 % CI: 1.68; 6.19). The colon cancer incidence risk increased with increasing age of workers, but other non-radiation factors were not shown to affect the results. This study supported the earlier results: no association was observed between the risk of colorectal cancer incidence and doses of occupational external gamma-ray or internal alpha-particle exposures.

Effectiveness of Colonoscopy Screening vs Sigmoidoscopy Screening in Colorectal Cancer

Randomized clinical screening trials have shown that sigmoidoscopy screening reduces colorectal cancer (CRC) incidence and mortality. Colonoscopy has largely replaced sigmoidoscopy for CRC screening, but long-term results from randomized trials on colonoscopy screening are still lacking. To estimate the additional screening benefit of colonoscopy compared with sigmoidoscopy. This comparative effectiveness simulation study pooled data on 358 204 men and women randomly assigned to sigmoidoscopy screening or usual care in 4 randomized sigmoidoscopy screening trials conducted in Norway, Italy, the US, and UK with inclusion periods in the years 1993 to 2001. The primary analysis of the study was conducted from January 19 to December 30, 2021. Invitation to endoscopic screening. Primary outcomes were CRC incidence and mortality. Using pooled 15-year follow-up data, colonoscopy screening effectiveness was estimated assuming that the efficacy of colonoscopy in the proximal colon was similar to that observed in the distal colon in the sigmoidoscopy screening trials. The simulation model was validated using data from Norwegian participants in a colonoscopy screening trial. This analysis included 358 204 individuals (181 971 women [51%]) aged 55 to 64 years at inclusion with a median follow-up time ranging from 15 to 17 years. Compared with usual care, colonoscopy prevented an estimated 50 (95% CI, 42-58) CRC cases per 100 000 person-years, corresponding to 30% incidence reduction (rate ratio, 0.70 [95% CI, 0.66-0.75]), and prevented an estimated 15 (95% CI, 11-19) CRC deaths per 100 000 person-years, corresponding to 32% mortality reduction (rate ratio, 0.68 [95% CI, 0.61-0.76]). The additional benefit of colonoscopy screening compared with sigmoidoscopy was 12 (95% CI, 10-14) fewer CRC cases and 4 (95% CI, 3-5) fewer CRC deaths per 100 000 person-years, corresponding to percentage point reductions of 6.9 (95% CI, 6.0-7.9) for CRC incidence and 7.6 (95% CI, 5.7-9.6) for CRC mortality. The number needed to switch from sigmoidoscopy to colonoscopy screening was 560 (95% CI, 486-661) to prevent 1 CRC case and 1611 (95% CI, 1275-2188) to prevent 1 CRC death. The findings of this comparative effectiveness study assessing long-term follow-up after CRC screening suggest that there was an additional preventive effect on CRC incidence and mortality associated with colonoscopy screening compared with sigmoidoscopy screening, but the additional preventive effect was less than what was achieved by introducing sigmoidoscopy screening where no screening existed. The results probably represent the upper limit of what may be achieved with colonoscopy screening compared with sigmoidoscopy screening.