Surveillance of the Colorectal Cancer Disparities Among Demographic Subgroups: A Spatial Analysis

Abstract

Objective: The literature suggests that colorectal cancer mortality in Texas is distributed inhomogeneously among specific demographic subgroups and in certain geographic regions over an extended period. To understand the extent of the demographic and geographic disparities, the present study examined colorectal cancer mortality in 15 demographic groups in Texas counties between 1990 and 2001. Methods:The Spatial Scan Statistic was used to assess the standardized mortality ratio, duration and age-adjusted rates of excess mortality, and their respective p-values for testing the null hypothesis of homogeneity of geographic and temporal distribution. Results:The study confirmed the excess mortality in some Texas counties found in the literature, identified 13 additional excess mortality regions, and found 4 health regions with persistent excess mortality involving several population subgroups. Conclusion:Health disparities of colorectal cancer mortality continue to exist in Texas demographic subpopulations. Health education and intervention programs should be directed to the at-risk subpopulations in the identified regions.Key Words: colorectal cancer, health disparities, public health informatics, Geographic Information Systems, spatial analysis. I n 2005, an estimated 56,290 deaths from colorectal cancer were expected in the United States, sustaining colorectal cancer as the third leading cause of cancer-related deaths among Americans.1 Recent studies suggest that screening is effective in decreasing colorectal cancer in both incidence and mortality by early detection and removal of precancerous lesions or polyps, and enhancing survival rates among colorectal cancer patients.2 Colorectal cancer is one of the most preventable types of cancer when detected at an early stage. However, while the 5-year survival rate for colorectal cancer is around 90% for those cases detected at an early stage, only about 37% of colorectal cancers were diagnosed at an early stage in 2004. 4 At the state level, between 1989 and 1998, the age-adjusted mortality rate for colorectal cancer in Texas actually increased by more than 20%.3 To target prevention and intervention efforts, it is important to understand the contributing risk factors for colorectal cancer affecting demographic groups living in different geographic regions. Key Points• Colorectal cancer mortality in Texas was found to be distributed inhomogeneously among specific demographic subgroups and in certain geographic regions over an extended period.• The study confirmed the excess mortality in some Texas counties reported in the literature, identified 13 additional excess mortality regions, and found 4 health regions with persistent excess mortality involving several population subgroups.• Health disparities in colorectal cancer mortality continue to exist in Texas demographic subpopulations.Health education and intervention programs should be enhanced to address the at-risk subpopulations in the identified regions.

The modifying effect of patient location on stage-specific survival following colorectal cancer using geosurvival models

“…Previous spatial analyses showed that CRC survival varied geographically across demographic subgroups [6, 59], but we now show that where CRC patients live may differentially impact the effect of tumor stage on survival. One mechanism by which stage at diagnosis and geography could interact to affect survival is through the biological processes of increased inflammation and oxidative stress [37].…”

“…Using newly developed statistical models, evidence is starting to emerge that not everyone is affected by their residential geographic location to the same extent and that the extent of the effects of location may depend on individual characteristics [6, 24–28]. However, most studies have focused on the interplay between geographic location and sociodemographic characteristics of study participants [25, 26, 28].…”

“…In CRC, the primary prognostic factor is stage at diagnosis [29, 30], and CRC survival decreases significantly with advanced stage at diagnosis [31]. While geographic disparities have been identified in stage at diagnosis [32–34], likely as a function of geographic disparities in screening [6, 19, 35, 36], little is known about the interplay between stage at diagnosis and subsequent geographic disparities in CRC survival. We hypothesize that the spatial pattern of CRC survival varies by stage at diagnosis.…”

Efficient mapping and geographic disparities in breast cancer mortality at the county-level by race and age in the U.S.

“…A recent county-level study described changes in geographic disparities over time (Schootman et al, 2010). Also, studies in Texas showed areas where breast cancer incidence was elevated and how risk factors affected the geographic disparity in incidence (Bambhroliya et al, 2012; Hsu et al, 2006). …”

Application of Geographic Information Systems (GIS) in the Study of Prostate Cancer Disparities: A Systematic Review

“…In Florida, northern and central counties exhibited the greatest racial disparities in late-stage PCa which was associated with lower censustract income and lower college education [43]. Additionally, the late-stage proportions decreased significantly from 1981 to 2007, however, the rate of decline varied greatly based on county location and racial groups [49]. This variation was suggested to be related to geographical disparities in the implementation of the Prostate Specific Antigen (PSA) screening [52].…”