Temporal Trends in Geographic and Sociodemographic Disparities in Colorectal Cancer Among Medicare Patients, 1973-2010

ANALYSIS OF THE TRACKING INITIATIVES OF COLORECTAL CANCER IN BRAZIL

BACKGROUND

Colorectal cancer (CRC) is an important public health problem, as it represents the world's third most diagnosed neoplasm and the fourth cause of mortality. Its prevention can be divided into primary, secondary, demonstrated by tracking techniques, and tertiary, which consists of cancer diagnosis in symptomatic patients. Despite presenting a high incidence, the mortality rates decreased in the past two decades in developed countries, while the opposite happened in underdeveloped countries. That is attributed to the increase of colorectal cancer tracking programs in developed countries, which allows the precocious diagnosis and treatment of precancerous injuries and CRC. In that manner, the American Cancer Society divides the secondary tracking methods in exams based on feces samples and visual analysis of the colon and rectum, indicating its initiation starting at 45 years old in lower-risk patients.

OBJECTIVE

Verify in an analytical way the actions of colorectal cancer tracking held in Brazil, as to evaluate the necessity of implementation of a national tracking program of CRC.

METHODS

The methodology was based on a descriptive-quantitative secondary study that correlated the incidence of CRC, its morbidity and mortality, and the impact of the precocious tracking programs. It included activities not reported in medical literature through personal contacts with coordinators of regional programs to compare with the existent data in the literature. It was used as a variable for the tracking strategies the exams held, and their respective results.

RESULTS

It described nine programs held in different regions in Brazil, using two screening methods for CRC: a noninvasive method that consists of the research of blood hidden in feces, being the majority through the FIT method, and an invasive method, having the colonoscopy as its representant. These initiatives were effective in the detection of early forms of this disease.

CONCLUSION

Despite the existence of several private tracking programs and the broad divulgation of the importance of the tracking and the early diagnosis of colorectal cancer, it was demonstrated that Brazil lacks a national program that patronizes the tracking methods, which reflects in the major prevalence of late diagnosis in the population.

Disparities in cancer incidence by rurality in California

BACKGROUND

Cancer rates in rural areas across the United States have different patterns than in urban areas. This study examines associations between rurality and incidence for the top 5 cancers in California and evaluates whether these associations vary jointly by sex, race, and ethnicity.

METHODS

We used 2015-2019 California Cancer Registry data to compare incidence rate ratios (IRRs) and trends for breast, prostate, lung, colorectal, and skin (melanoma) cancers. We leveraged census tract aggregation zones and 7 levels of percentage rural population (0%, >0% to <10%, 10% to <20%, 20% to <30%, 30% to <40%, 40% to <50%, and 50+%).

RESULTS

Zones with higher proportions of rural population were significantly associated with lower incidence of female breast cancer and prostate cancer, though the trends were not statistically significant overall. Zones with higher proportions of rural population were significantly associated with higher incidence of lung cancer and melanoma. There were no statistically significant trends for colorectal cancer overall. Comparing areas with 50% and over rural population with areas with 0% rural population, the IRR for lung cancer in Hispanic females was higher (IRR = 1.43, 95% confidence interval [CI] = 1.17 to 1.74) than in Hispanic males (IRR = 0.90, 95% CI = 0.72 to 1.11). Also, in areas with 50% or more rural population, the IRR for melanoma was higher in Hispanic females (IRR = 1.75, 95% CI = 1.23 to 2.45) than non-Hispanic White females (IRR = 0.87, 95% CI = 0.80 to 0.95).

CONCLUSIONS

Our findings show that rurality is associated with cancer incidence and underscore the importance of jointly examining rural disparities with sex, race, and ethnicity by cancer site.

Colorectal Cancer Survival Trends in the United States From 1992 to 2018 Differ Among Persons From Five Racial and Ethnic Groups According to Stage at Diagnosis: A SEER-Based Study

Introduction

Survival following colorectal cancer (CRC) has improved in the US since 1975, but there is limited information on stage-specific survival trends among racial and ethnic subgroups.

Objectives

The purpose of this study was to estimate and compare trends in 1- and 5-year CRC cause-specific survival in the United States by both stage and race/ethnicity.

Methods

We performed a retrospective cohort study of individuals diagnosed with CRC using the 1992-2018 Surveillance, Epidemiology and End Results (SEER) database. We estimated and compared time trends in 1- and 5-year survival for CRC stage by race/ethnicity.

Results

Data from 399 220 individuals diagnosed with CRC were available. There were significant differences in stage-specific 1-year survival trends by race and ethnicity. Differences were most notable for distant stage CRC: survival probabilities increased most consistently for non-Hispanic American Indian/Alaska Native (AIAN) and Black (NHB) persons, but their trend lines were lower than those of Hispanic, and non-Hispanic Asian/Pacific Islander (API) and White (NHW) persons, whose initially greater gains appear to be slowing. Although the data do not support significant racial/ethnic differences in 5-year CRC survival trends by stage, AIAN and NHB persons have the lowest average survival probabilities for multiple CRC stages, and no racial/ethnic group has 5-year survival probabilities above 20% for distant-stage CRC.

Conclusion

Although there has been an overall improvement in adjusted CRC-specific survival probabilities since 1992, AIAN and NHB persons continue to experience worse prognosis than those of other races/ethnicities. This highlights the importance of reinvigorating efforts to understand the causes of mortality in CRC, including those which may differ according to an individual’s race or ethnicity.

Rural-Urban Disparities in Cancer Outcomes: Opportunities for Future Research

Cancer care disparities among rural populations are increasingly documented and may be worsening, likely because of the impact of rurality on access to state-of-the-art cancer prevention, diagnosis, and treatment services, as well as higher rates of risk factors such as smoking and obesity. In 2018, the American Society of Clinical Oncology undertook an initiative to understand and address factors contributing to rural cancer care disparities. A key pillar of this initiative was to identify knowledge gaps and promote the research needed to understand the magnitude of difference in outcomes in rural vs nonrural settings, the drivers of those differences, and interventions to address them. The purpose of this review is to describe continued knowledge gaps and areas of priority research to address them. We conducted a comprehensive literature review by searching the PubMed (Medline), Embase, Web of Science, and Cochrane Library databases for studies published in English between 1971 and 2021 and restricted to primary reports from populations in the United States and abstracted data to synthesize current evidence and identify continued gaps in knowledge. Our review identified continuing gaps in the literature regarding the underlying causes of rural-urban disparities in cancer outcomes. Rapid advances in cancer care will worsen existing disparities in outcomes for rural patients without directed effort to understand and address barriers to high-quality care in these areas. Research should be prioritized to address ongoing knowledge gaps about the drivers of rurality-based disparities and preventative and corrective interventions.

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.

Time Trends in Colorectal Cancer Incidence Rates by Income and Age at Diagnosis in Canada From 1992 to 2016

IMPORTANCE

Colorectal cancer (CRC) incidence rates among individuals younger than 50 years have been increasing in many countries, including Canada. Whether changes in CRC incidence rates over time are uniform across income and age groups remains unknown.

OBJECTIVE

To examine time trends in CRC incidence rates in Canada by area-level average household income by age group from 1992 to 2016.

DESIGN, SETTING, AND PARTICIPANTS

A population-based, retrospective cohort study was conducted including individuals aged 20 years or older diagnosed with CRC in Canada (excluding Québec) from 1992 to 2016. Data analysis was performed from February 27 to September 28, 2020.

EXPOSURES

Average household income was determined by linking an individual's postal code at diagnosis from the Canadian Cancer Registry to Canadian Census data. Average household income was then categorized into quintiles from Q1, the lowest income group, to Q5, the highest income group.

MAIN OUTCOMES AND MEASURES

Canadian Cancer Registry data were used to determine CRC incidence rates from 1992 to 2016.

RESULTS

There were 340 790 cases of CRC diagnosed from 1992 to 2016; 11 790 cases (3.5%) were diagnosed in individuals aged 20 to 44 years. Colorectal cancer incidence rates for individuals aged 20 to 44 years increased for all income quintiles, with higher incidence rates in the lower income quintiles. The ratio between the maximum and minimum CRC incidence rates was highest among the 20- to 29-year age group from 1992 to 1996 (ratio, 2.67; 95% CI, 1.47-4.83) and 2012 to 2016 (ratio, 2.00; 95% CI, 1.29-3.10). For individuals aged 45 to 49 years, CRC incidence rates increased only for individuals in the lower income quintiles (eg, incidence in Q1, 1992-1996 vs 2012-2016: 4.54 per 100 000 [95% CI, 4.05-5.03] vs 5.37 per 100 000 [95% CI, 4.91-5.83]), with higher incidence rates in the high income quintiles (eg, incidence rate for Q5 in 1992-1996: 5.92 per 100 000 [95% CI, 5.36-6.48]). For those aged 50 to 54 years, CRC incidence rates were stable for all income quintiles, with less variability between income quintiles. For individuals aged 55 to 74 years, CRC incidence rates were stable or decreased for all income quintiles (eg, incidence rate for age 55-59 years in Q5, 1992-1992 vs 2012-2016: 17.97 per 100 000 [95% CI, 16.76-19.18] vs 14.56 per 100 000 [95% CI, 13.80-15.32]), and there was less variability in the rates by income quintile, particularly from 2012 to 2016. After age 75 years, CRC incidence rates were stable or decreased (eg, incidence rate for age 75-79 years, 1992-1996 vs 2012-2016: 66.43 per 100 000 [65.00-67.87] vs 57.34 per 100 000 [56.24-58.45]), were highest for the lower income quintiles, and variability between income quintiles increased relative to younger age groups.

CONCLUSIONS AND RELEVANCE

In this cohort study, trends in CRC incidence rates in Canada differed by age group and income quintile. These results suggest that, although population-based screening can reduce income disparities, targeted interventions and further research are needed to address the increasing CRC incidence rate among younger individuals in Canada, particularly in the lower income quintiles.

Trends in Sociodemographic Disparities in Colorectal Cancer Staging and Survival: A SEER-Medicare Analysis

Race, ethnicity, and socioeconomic status are known to influence staging and survival in colorectal cancer (CRC). It is unclear how these relationships are affected by geographic factors and changes in insurance coverage for CRC screening. We examined the temporal trends in the association between sociodemographic and geographic factors and staging and survival among Medicare beneficiaries.

Reaching Rural Residents to Identify Colorectal Cancer Education and Intervention Targets

Disparities in cancer screening and care in rural communities warrant the need to determine effective ways to reach, engage, and educate the community residents. The purpose of this cross-sectional study was to pilot methods to engage rural residents in colorectal cancer (CRC) research and education activities and assess knowledge of CRC guidelines, symptoms, and screening behaviors in this sample. The community-engaged research approach was employed to develop and distribute a CRC knowledge and screening behavior assessment using various methods such as email and community drop boxes placed throughout the community. Bivariate analysis assessed the relationship between age and CRC knowledge items. Three hundred ninety-one surveys were returned with most received from community drop boxes (60%) followed by educational events (23%). The most ineffective method to distribute surveys was through community events. Most individuals were knowledgeable of CRC symptoms (70%) and screening facts (67%). Bivariate analysis showed that individuals 50 years or older had significantly more knowledge of CRC risks and screening than those under the age of 50. This study highlights the potential of community drop boxes as an effective method for engaging rural communities. Further, findings from the survey highlight the need to focus CRC education on younger individuals in which CRC incidence has increased.

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

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

Socioeconomic Status in Relation to Risks of Major Gastrointestinal Cancers in Chinese Adults: A Prospective Study of 0.5 Million People

BACKGROUND

Low socioeconomic status (SES) is associated with higher risk of certain gastrointestinal (e.g., colorectal, pancreatic, and liver) cancers in Western populations. Evidence is very limited in China, where correlates and determinants of SES differ from those in the West.

METHODS

The prospective China Kadoorie Biobank recruited 512,715 adults (59% women, mean age 51 years) from 10 (5 urban, 5 rural) regions. During 10 years of follow-up, 27,940 incident cancers (including 3,061 colorectal, 805 pancreatic, and 2,904 liver) were recorded among 510,131 participants without prior cancer at baseline. Cox regression was used to estimate adjusted HRs for specific cancers associated with area-level (e.g., per capita gross domestic product, disposable income) and individual-level (e.g., education, household income) SES.

RESULTS

Area-level SES and household income showed positive associations with incident colorectal and pancreatic cancers and inverse associations with liver cancer (P _trend < 0.05). Education showed no association with colorectal cancer but inverse associations with pancreatic and liver cancers, with adjusted HRs comparing university to no formal schooling being 1.05 [95% confidence interval (CI), 0.85-1.29], 0.49 (95% CI, 0.28-0.85), and 0.61 (95% CI, 0.47-0.81), respectively. Potential risk factors (e.g., smoking, alcohol) partly explained the inverse associations of education with pancreatic and liver cancers (17.6% and 60.4%), respectively.

CONCLUSIONS

Among Chinese adults, the associations of SES with gastrointestinal cancers differed by cancer type and SES indicator. Potential risk factors partially explained the inverse associations of education with pancreatic and liver cancers.

IMPACT

The different associations between SES with gastrointestinal cancers may inform cancer prevention strategies.

Comparisons of metastatic patterns of colorectal cancer among patients by age group: a population-based study

Population-based evaluations of the incidence of metastatic colorectal cancer at diagnosis among different age groups are lacking. Therefore, we investigated the effects of age at diagnosis on metastatic colorectal cancer and patients’ prognoses. The Surveillance, Epidemiology, and End Results database was used to identify patients diagnosed with metastatic colorectal cancer. Multivariate Cox regression analyses were performed to identify factors associated with poor survival. The Kaplan–Meier analysis was used to estimate survival differences between the subgroups. We identified 30,333 adult patients diagnosed with metastatic colorectal cancer between 2010 and 2014. The younger and middle-aged groups had better survival than the older group when brain metastasis was not involved. The liver was the most common site of metastasis followed by the liver and lung combined. Age at diagnosis was an independent factor in patients’ survival. Survival differences between two and three-sites of metastases were found in the middle-aged and older groups but not in the younger group. No survival differences between three and four sites of metastases were found in any of the age groups. Therefore, the incidence and prognosis of metastatic sites for metastatic colorectal cancer varied by age group.

Clinicopathologic and epidemiological characteristics of prognostic factors in post-surgical survival of colorectal cancer patients in Jiangsu Province, China

Poor survival among colorectal cancer (CRC) patients has been widely associated with clinico-epidemiological features and treatment regimen. In Jiangsu (China), however, it is not known which one of the prognostic factors explains the survival disparities among patients with CRC. This prospective study using 1078 patients (stages I-IV) that underwent surgery at Jiangsu Hospital, explored the relevant factors affecting the prognoses of right-side colon cancer (RCC), left-side colon cancer (LCC) and rectal cancer (ReC) patients. Of these cases, 234 (21.7%), 241 (22.4%) and 603 (55.9%) were found to have RCC, LCC and ReC respectively. Compared to LCC, RCC exhibited a greater proportion of older patients, poorly differentiated carcinomas, higher T-stage and higher TNM-stage. The overall survival (OS) for RCC was 60 vs.78 or 77 months for LCC or ReC respectively (P = 0.030). There were no significant differences in OS between LCC and ReC across the subgroups (P = 0.633). In multivariate analysis, RCC patients had age (>60 vs. ≤60 years, HR = 1.529, P = 0.019), N-stage (N1 vs. N0, HR = 4.056, P = 0.012) and M-stage (M1 vs. M0, HR = 3.442, P < 0.0001) as independent prognostic factors, whereas smoking status was found to be a predictor of mortality (smoker vs. nonsmoker, HR = 2.343, P = 0.017) for LCC. In addition, age (>60 vs. ≤60 years, HR = 2.199, P < 0.0001), alcohol consumption (drinker vs. nondrinker, HR = 0.510, P = 0.034), tumor grade (Poor vs. well/moderate, HR = 2.759, P = 0.031) and T-stage (T3-4 vs. T1-2, HR = 1.742, P < 0.0001) were found to be predictors of mortality for ReC. There were significant pairwise interactions across subgroups. Furthermore, significant differences were observed for LCC vs. RCC (OS, HR = 0.783, P = 0.039), but no statistically significant differences for ReC vs. RCC (P = 0.149) and LCC vs. ReC (P = 0.355). Nevertheless, significant differences remained between ReC vs. RCC for male (HR = 0.591, P = 0.009), drinker (HR = 0.396, P = 0.005), rural resident (HR = 0.437,P = 0.022), tumor grade (well/moderate, HR = 0.475, P = 0.022), T-stage (T1-2, HR = 0.362, P = 0.001), N-stage (N0, HR = 0.604, P = 0.011), M-stage(M0, HR = 0.401, P = 0.006) and TNM-stage (I-II, HR = 0.567, P = 0.005). Statistically significant differences were observed for LCC vs. RCC for gender (female, HR = 0.495, P = 0.003) and T-stage (T1-2, HR = 0.417, P = 0.010) as well as for LCC vs. ReC in patients with smoking habits (HR = 1.951, P = 0.002) and M-stage (M0, HR = 2.291, P = 0.003). These findings suggest that the variations in CRC post-surgical survival in China may be primarily explained with the clinicopathologic features and epidemiological characteristic of the patients. Patients with RCC had significantly worse OS compared to both LCC and ReC in several subgroups.

Colorectal cancer screening: Understanding the health literacy needs of hispanic rural residents

Purpose

Hispanics residing in rural areas are among those who are least likely to be screened for colorectal cancer (CRC) and more likely to present with late stage CRC than other racial or ethnic groups. We conducted a pilot study utilizing a mixed-method approach to explore perceptions of CRC and CRC screening among Hispanic adults residing in South Texas rural communities and to identify health literacy needs associated with CRC screening uptake.

Methods

A convenience sample of 58 participants, aged 35–65, were recruited to complete questionnaires and participate in focus groups, ranging in size from 4 to 13 participants. Six focus groups were conducted across 3 adjacent rural counties. A semi-structured moderator's guide was designed to elicit discussion about participants' experiences, knowledge, and perceptions of CRC and CRC screening.

Findings

Lack of knowledge of CRC and CRC screening as cancer prevention was a common theme across focus groups. A majority, 59%, reported never been screened. Thirty-nine percent reported they had been screened for colon cancer and 5% reported they did not know if they had been screened. Participants with lower educational levels perceived themselves at high risk for developing CRC polyps, would not want to know if they had CRC, and if they did have CRC, would not want to know until the very end. Limited information about CRC and CRC screening, a lack of specialized providers, limited transportation assistance, and compromised personal privacy in small-town medical facilities were perceived to be barriers to CRC screening.

Conclusions

Low screening rates persist among rural Hispanics. Improving CRC screening literacy and addressing factors unique to rural Hispanics may be a beneficial strategy for reducing screening disparities in this at-risk population.

Spatially varying effects of predictors for the survival prediction of nonmetastatic colorectal Cancer

Background

An increasing number of studies have identified spatial differences in colorectal cancer survival. However, little is known about the spatially varying effects of predictors in survival prediction modeling studies of colorectal cancer that have focused on estimating the absolute survival risk for patients from a wide range of populations. This study aimed to demonstrate the spatially varying effects of predictors of survival for nonmetastatic colorectal cancer patients.

Methods

Patients diagnosed with nonmetastatic colorectal cancer from 2004 to 2013 who were followed up through the end of 2013 were extracted from the Surveillance Epidemiology End Results registry (Patients: 128061). The log-rank test and the restricted mean survival time were used to evaluate survival outcome differences among spatial clusters corresponding to a widely used clinical predictor: stage determined by AJCC 7th edition staging system. The heterogeneity test, which is used in meta-analyses, revealed the spatially varying effects of single predictors. Then, considering the above predictors in a standard survival prediction model based on spatially clustered data, the spatially varying coefficients of these models revealed that some covariate effects may not be constant across the geographic regions of the study. Then, two types of survival prediction models (a statistical model and a machine learning model) were built; these models considered the predictors and enabled survival prediction for patients from a wide range of geographic regions.

Results

Based on univariate and multivariate analysis, some prognostic factors, such as “TNM stage”, “tumor size” and “age at diagnosis,” have significant spatially varying effects among different regions. When considering these spatially varying effects, machine learning models have fewer assumption constraints (such as proportional hazard assumptions) and better predictive performance compared with statistical models. Upon comparing the concordance indexes of these two models, the machine learning model was found to be more accurate (0.898[0.895,0.902]) than the statistical model (0.732 [0.726, 0.738]).

Conclusions

Based on this study, it’s recommended that the spatially varying effect of predictors should be considered when building survival prediction models involving large-scale and multicenter research data. Machine learning models that are not limited by the requirement of a statistical hypothesis are promising alternative models.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4985-2) contains supplementary material, which is available to authorized users.

Proximal shift of colorectal cancer with increasing age in different ethnicities

Background

Studies have indicated a variation in colon cancer pathology with increased age. More findings have also suggested differences in genetics, biology, and demography in terms of ethnicity. Large-scale studies closely examining tumor location shift with aging and ethnicity are scarce.

Objective

We compared the tumor location shift with aging and the difference in survival based on tumor location by age group among the African-American, White, and Asian/Pacific Islander patients with colorectal cancer.

Materials and methods

We collected 270,390 cases from the Surveillance, Epidemiology, and End Results database between 2004 and 2014. Ethnicity distribution between younger (age <70 years) and older (age ≥70 years) patients was analyzed using univariate and multivariate logistic regression. The Kaplan–Meier method was used to compare the tumor location survival difference in the African-American, White, and Asian/Pacific Islander patients.

Results

Larger tumors, female sex, M0, advanced N stage, no treatment, moderate to poor differentiation, total number of lymph nodes evaluated >12, and right-sided colon cancer were more common in patients aged ≥70 years. More adverse prognosis was found in younger patients compared to older patients. Tumor location frequency differed based on age; the most pronounced differences were found in White patients. The right-sided colon cancer survival inferiority was present only in White patients.

Conclusion

Our findings support the premise of etiological and carcinogenic differences based on tumor location and between younger and older patients.

Utility and Generalizability of Multistate, Population-Based Cancer Registry Data for Rural Cancer Surveillance Research in the United States

More than 46 million Americans live in rural areas, but rural populations remain relatively understudied in cancer disparities research. However, several analyses of multistate cancer registry data that describe the rural cancer incidence burden have been recently published. In light of this, our article aims to characterize the utility and generalizability of multistate, population-based cancer registry datasets for rural cancer surveillance research. First, we describe the accessibility, geographic coverage, available variables, and strengths and weaknesses of five data sources. Second, we evaluate two of these data sources-the North American Association of Central Cancer Registries (NAACCR) public use dataset (93% population coverage) and the Surveillance Epidemiology and End Results (SEER) 18 dataset (28% population coverage)-on their characterization of rural-urban cancer incidence rates and sociodemographic representation. The five data sources varied in geographic coverage and extent of available variables. SEER 18's cancer rates sociodemographic representation differed from the more geographically representative NAACCR data. We suggest that SEER increase its geographic coverage to improve their generalizability and to take advantage of their utility to assess disparities along the cancer control continuum. We also suggest that non-SEER data sources be utilized more frequently to capitalize on their extensive geographic coverage. Cancer Epidemiol Biomarkers Prev; 27(11); 1252-60. ©2018 AACR.

Spatio-temporal analysis of the incidence of colorectal cancer in Guangzhou, 2010-2014

INTRODUCTION

Colorectal cancer (CRC) is a common type of neoplasm. This study examined the spatio-temporal distribution of the CRC incidence in Guangzhou during 2010-2014.

METHODS

Colorectal cancer incidence data were obtained from the Guangzhou Cancer Registry System. Spatial autocorrelation analysis and a retrospective spatio-temporal scan were used to assess the spatio-temporal cluster distribution of CRC cases.

RESULTS

A total of 14,618 CRC cases were registered in Guangzhou during 2010-2014, with a crude incidence of 35.56/100,000 and an age-standardized rate of incidence by the world standard population (ASRIW) of 23.58/100,000. The crude incidence increased by 19.70% from 2010 (32.88/100,000) to 2014 (39.36/100,000) with an average annual percentage change (AAPC) of 4.33%. The AAPC of ASRIW was not statistically significant. The spatial autocorrelation analysis revealed a CRC incidence hot spot in central urban areas in Guangzhou City, which included 25 streets in southwestern Baiyun District, northwestern Haizhu District, and the border region between Liwan and Yuexiu Districts. Three high- and five low-incidence clusters were identified according to spatio-temporal scan of CRC incidence clusters. The high-incidence clusters were located in central urban areas including the border regions between Baiyun, Haizhu, Liwan, and Yuexiu Districts.

CONCLUSIONS

This study revealed the spatio-temporal cluster pattern of the incidence of CRC in Guangzhou. This information can inform allocation of health resources for CRC screening.

Rural-Urban Differences in Cancer Incidence and Trends in the United States

Background: Cancer incidence and mortality rates in the United States are declining, but this decrease may not be observed in rural areas where residents are more likely to live in poverty, smoke, and forego cancer screening. However, there is limited research exploring national rural-urban differences in cancer incidence and trends.Methods: We analyzed data from the North American Association of Central Cancer Registries' public use dataset, which includes population-based cancer incidence data from 46 states. We calculated age-adjusted incidence rates, rate ratios, and annual percentage change (APC) for: all cancers combined, selected individual cancers, and cancers associated with tobacco use and human papillomavirus (HPV). Rural-urban comparisons were made by demographic, geographic, and socioeconomic characteristics for 2009 to 2013. Trends were analyzed for 1995 to 2013.Results: Combined cancers incidence rates were generally higher in urban populations, except for the South, although the urban decline in incidence rate was greater than in rural populations (10.2% vs. 4.8%, respectively). Rural cancer disparities included higher rates of tobacco-associated, HPV-associated, lung and bronchus, cervical, and colorectal cancers across most population groups. Furthermore, HPV-associated cancer incidence rates increased in rural areas (APC = 0.724, P < 0.05), while temporal trends remained stable in urban areas.Conclusions: Cancer rates associated with modifiable risks-tobacco, HPV, and some preventive screening modalities (e.g., colorectal and cervical cancers)-were higher in rural compared with urban populations.Impact: Population-based, clinical, and/or policy strategies and interventions that address these modifiable risk factors could help reduce cancer disparities experienced in rural populations. Cancer Epidemiol Biomarkers Prev; 27(11); 1265-74. ©2017 AACR.