Spatial accessibility to colonoscopy and its role in predicting late-stage colorectal cancer

Gravity models for potential spatial healthcare access measurement: a systematic methodological review

BACKGROUND

Quantifying spatial access to care-the interplay of accessibility and availability-is vital for healthcare planning and understanding implications of services (mal-)distribution. A plethora of methods aims to measure potential spatial access to healthcare services. The current study conducts a systematic review to identify and assess gravity model-type methods for spatial healthcare access measurement and to summarize the use of these measures in empirical research.

METHODS

A two-step approach was used to identify (1) methodological studies that presented a novel gravity model for measuring spatial access to healthcare and (2) empirical studies that applied one of these methods in a healthcare context. The review was conducted according to the PRISMA guidelines. EMBASE, CINAHL, Web of Science, and Scopus were searched in the first step. Forward citation search was used in the second step.

RESULTS

We identified 43 studies presenting a methodological development and 346 empirical application cases of those methods in 309 studies. Two major conceptual developments emerged: The Two-Step Floating Catchment Area (2SFCA) method and the Kernel Density (KD) method. Virtually all other methodological developments evolved from the 2SFCA method, forming the 2SFCA method family. Novel methodologies within the 2SFCA family introduced developments regarding distance decay within the catchment area, variable catchment area sizes, outcome unit, provider competition, local and global distance decay, subgroup-specific access, multiple transportation modes, and time-dependent access. Methodological developments aimed to either approximate reality, fit a specific context, or correct methodology. Empirical studies almost exclusively applied methods from the 2SFCA family while other gravity model types were applied rarely. Distance decay within catchment areas was frequently implemented in application studies, however, the initial 2SFCA method remains common in empirical research. Most empirical studies used the spatial access measure for descriptive purposes. Increasingly, gravity model measures also served as potential explanatory factor for health outcomes.

CONCLUSIONS

Gravity models for measuring potential spatial healthcare access are almost exclusively dominated by the family of 2SFCA methods-both for methodological developments and applications in empirical research. While methodological developments incorporate increasing methodological complexity, research practice largely applies gravity models with straightforward intuition and moderate data and computational requirements.

Comprehensive analysis of the potential role and prognostic value of sine oculis homeobox homolog family in colorectal cancer

BACKGROUND

Several genes, important for development, are reduced or silenced in adulthood, and their abnormal expression has been related to the occurrence and development of malignant tumors. Human sine oculis homeobox homolog (SIX) proteins belong to the homeobox family and play important roles in the development of different organs. Importantly, SIXs are predicted to have chromatin-binding and DNA-binding transcription factor activity with reported roles in cancers. However, a comprehensive analysis of SIXs in colorectal cancers (CRCs) has not been performed.

AIM

To explore the expression pattern of six SIX proteins in CRCs and their relationship with the clinicopathological parameters of CRC patients as well as investigate the potential utilization of SIXs as novel prognostic indicators in CRCs.

METHODS

The expression level of SIXs in normal tissues of different organs and related cancerous tissues was analyzed in the Human Protein Atlas. Kaplan-Meier Plotter and GEPIA2 were used to analyze the prognostic values of SIXs. To analyze the potential signaling pathways with SIX family involvement, LinkedOmics was used to perform Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses of SIX4-related genes. Subsequently, immunohistochemical experiments were performed on CRC tissues and adjacent normal tissues, and we examined the SIX4 expression level in 87 pairs of patients with tissue microarray. The relationship between SIX4 and clinicopathological parameters in CRC patients was tested using the χ² test and Fisher’s exact probability to verify the results of the database analysis.

RESULTS

The RNA levels of SIX1-4 and SIX6 were relatively low in normal human tissues, while SIX5 was highly expressed at both the RNA and protein levels. However, the protein level of SIX4 was found to be elevated in various malignancies. In CRC tissues, SIX1, SIX2 and SIX4 were elevated in cancer tissues compared with adjacent normal tissue. Among all SIXs, a high level of SIX4 was found to be associated with poor overall and disease-free survival in patients with CRC. For different clinicopathological parameters, increased SIX4 expression was positively correlated with advanced CRC. The top 50 SIX4-related genes were involved with oxidative phosphorylation and the respiratory chain signaling pathways.

CONCLUSION

The current results provided a comprehensive analysis of the expression and prognostic values of SIX family members in CRC. Among different SIXs, SIX4 plays an oncogenic role in CRC to promote the development of malignancy. In CRC, SIX4 mRNA and protein expression is higher than that in normal tissues and associated with shorter CRC patient survival, suggesting that SIX4 may be a potential therapeutic target for treatment of CRC patients.

Multiscale analysis of cancer service areas in the United States

The purpose of delineating Cancer Service Areas (CSAs) is to define a reliable unit of analysis, more meaningful than geopolitical units such as states and counties, for examining geographic variations of the cancer care markets using geographic information systems (GIS). This study aims to provide a multiscale analysis of the U.S. cancer care markets based on the 2014-2015 Medicare claims of cancer-directed surgery, chemotherapy, and radiation. The CSAs are delineated by a scale-flexible network community detection algorithm automated in GIS so that the patient flows are maximized within CSAs and minimized between them. The multiscale CSAs include those comparable in size to those 4 census regions, 9 divisions, 50 states, and also 39 global optimal CSAs that generates the highest modularity value. The CSAs are more effective in capturing the U.S. cancer care markets because of its higher localization index, lower cross-border utilizations, and shorter travel time. The first two comparisons reveal that only a few regions or divisions are representative of the underlying cancer care markets. The last two comparisons find that among the 39 CSAs, 54% CSAs comprise multiple states anchored by cities near inner state borders, 28% are single-state CSAs, and 18% are sub-state CSAs. Their (in)consistencies across state borders or within each state shed new light on where the intervention of cancer care delivery or the adjustment of cancer care costs are needed to meet the challenges in the U.S. cancer care system. The findings could guide stakeholders to target public health policies for more effective coordination of cancer care in improving outcomes and reducing unnecessary costs.

Potential of six-transmembrane epithelial antigen of the prostate 4 as a prognostic marker for colorectal cancer

BACKGROUND

Immune cells play a role in the regulation of tumor cell behavior, and accumulating evidence supports their significance in predicting outcomes and therapeutic efficacy in colorectal cancers (CRC). Human six-transmembrane epithelial antigen of the prostate (STEAP) proteins have been recognized and utilized as promising targets for cell- and antibody-based immunotherapy. One STEAP family member, STEAP4, is expected to be an attractive biomarker for the immunotherapy of prostate and breast cancer. However, the immunotherapeutic role of STEAP4 for colorectal carcinomas has not been demonstrated.

AIM

To explore the expression pattern of STEAPs in CRC and their relationship with immune infiltration, and investigate the potential utilization of STEAPs as novel prognostic indicators in colorectal carcinomas.

METHODS

The expression level of STEAPs in CRC was evaluated using various open-resource databases and online tools to explore the expression characteristics and prognostic significance of STEAPs, as well as their correlation with immune-related biomarkers, such as immune infiltration. Immunohistochemical (IHC) experiments were subsequently performed to verify the database conclusions.

RESULTS

The levels of STEAPs in CRC were inconsistent. The expression of STEAPs 1-3 in CRC was not significantly different from that in normal tissues. However, STEAP4 mRNA levels were significantly lower in CRC than in normal tissue and were positively correlated with immune-related biomarkers, such as immune cell infiltration, immune stimulation, major histocompatibility complex levels, and chemokines. Interestingly, the expression of STEAP4 in microsatellite instability-high CRC subtype was higher than that in microsatellite stability subtype. IHC staining was performed on colon cancer tissue samples and showed that high expression of STEAP4 in adjacent tissues positively correlated with immune-related biomarkers, including MLH1, MLH6, and PMS2, but negatively correlated with programmed death ligand 1, to varying degrees.

CONCLUSION

Our results provide an analysis of the expression of STEAP family members in CRC. Among different STEAP family members, STEAP4 plays a different role in CRC compared to STEAPs 1-3. In CRC, STEAP4 expression is not only lower than that in normal tissues, but it is also positively correlated with immune infiltration and immune-related biomarkers. These findings suggest that STEAP4 may be a potential biomarker for predicting CRC immune infiltration status.

The Problem Of The Color Line: Spatial Access To Hospital Services For Minoritized Racial And Ethnic Groups

Examining how spatial access to health care varies across geography is key to documenting structural inequalities in the United States. In this article and the accompanying StoryMap, our team identified ZIP Code Tabulation Areas (ZCTAs) with the largest share of minoritized racial and ethnic populations and measured distances to the nearest hospital offering emergency services, trauma care, obstetrics, outpatient surgery, intensive care, and cardiac care. In rural areas, ZCTAs with high Black or American Indian/Alaska Native representation were significantly farther from services than ZCTAs with high White representation. The opposite was true for urban ZCTAs, with high White ZCTAs being farther from most services. These patterns likely result from a combination of housing policies that restrict housing opportunities and federal health policies that are based on service provision rather than community need. The findings also illustrate the difficulty of using a single metric-distance-to investigate access to care on a national scale.

Geographic determinants of colorectal cancer in Louisiana

Purpose

Currently, rural residents in the United States (US) experience a greater cancer burden for tobacco-related cancers and cancers that can be prevented by screening. We aim to characterize geographic determinants of colorectal cancer (CRC) incidence in Louisiana due to rural residence and other known geographic risk factors, area socioeconomic status (SES), and cultural region (Acadian or French-speaking).

Methods

Primary colorectal cancer diagnosed among adults 30 years and older in 2008–2017 were obtained from the Louisiana Tumor Registry. Population and social and economic data were obtained from US Census American Community Survey. Rural areas were defined using US Department of Agriculture 2010 rural–urban commuting area codes. Estimates of relative risk (RR) were obtained from multilevel binomial regression models of incidence.

Results

The study population was 16.1% rural, 18.4% low SES, and 17.9% Acadian. Risk of CRC was greater among rural white residents (RR Women: 1.09(1.02–1.16), RR Men: 1.11(1.04–1.18)). Low SES was associated with increased CRC for all demographic groups, with excess risk ranging from 8% in Black men (RR: 1.08(1.01–1.16)) to 16% in white men (RR: 1.16(1.08–1.24)). Increased risk in the Acadian region was greatest for Black men (RR: 1.21(1.10–1.33)) and women (RR: 1.21(1.09–1.33)). Rural–urban disparities in CRC were no longer significant after controlling for SES and Acadian region.

Conclusion

SES remains a significant determinant of CRC disparities in Louisiana and may contribute to observed rural–urban disparities in the state. While the intersectionality of CRC risk factors is complex, we have confirmed a robust regional disparity for the Acadian region of Louisiana.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10552-021-01546-7.

Diverse expression patterns of mucin 2 in colorectal cancer indicates its mechanism related to the intestinal mucosal barrier

BACKGROUND

Abnormal expression patterns of mucin 2 (MUC2) have been reported in a variety of malignant tumors and precancerous lesions. Reduced MUC2 expression in the intestinal mucosa, caused by various pathogenic factors, is related to mechanical dysfunction of the intestinal mucosa barrier and increased intestinal mucosal permeability. However, the relationship between MUC2 and the intestinal mucosal barrier in patients with colorectal cancer (CRC) is not clear.

AIM

To explore the relationship between MUC2 and intestinal mucosal barrier by characterizing the multiple expression patterns of MUC2 in CRC.

METHODS

Immunohistochemical staining was performed on intestinal tissue specimens from 100 CRC patients, including both cancer tissues and adjacent normal tissues. Enzyme-linked immunosorbent assays were performed on preoperative sera from 66 CRC patients and 20 normal sera to detect the serum levels of MUC2, diamine oxide (DAO), and D-lactate (D-LAC). The relationship between MUC2 expression and clinical parameters was calculated by the χ² test or Fisher’s exact test. Prognostic value of MUC2 was evaluated by Kaplan-Meier curve and log-rank tests.

RESULTS

Immunohistochemical staining of 100 CRC tissues showed that the expression of MUC2 in cancer tissues was lower than that in normal tissues (54% vs 79%, P < 0.05), and it was correlated with tumor-node-metastasis (TNM) stage and lymph node metastasis in CRC patients (P < 0.05). However, the serum level of MUC2 in CRC patients was higher than that in normal controls, and was positively associated with serum levels of human DAO (χ² = 3.957, P < 0.05) and D-LAC (χ² = 7.236, P < 0.05), which are the biomarkers of the functional status of the intestinal mucosal barrier. And the serum level of MUC2 was correlated with TNM stage, tumor type, and distant metastasis in CRC patients (P < 0.05). Kaplan-Meier curves showed that decreased MUC2 expression in CRC tissues predicted a poor survival.

CONCLUSION

MUC2 in tissues may play a protective role by participating in the intestinal mucosal barrier and can be used as an indicator to evaluate the prognosis of CRC patients.