Geographic Variations in Cervical Cancer
Geographic Variations in Advanced Stage Cervical Cancers in California, 2009-2013
In 2013, 1,401 Californians were diagnosed with invasive cancers of the cervix, and 492 deaths due to the disease occurred. With regular cervical cancer screening in the form of Pap tests, early detection and prevention of cervical cancer is possible. If caught in the early stages, the survival rate of localized cervical cancer (when the cancer is confined to the cervix) is 92.5 percent. Unfortunately, in 2013, 55.5 percent of all invasive cervical cancers diagnosed in California were diagnosed at an advanced stage, after the disease spread beyond the cervix to other parts of the body. In 2013, only 79 percent of women ages 21 and older reported having a Pap test within the past 3 years.1 Greater awareness of cervical cancer screening and accessibility to primary health care is needed to improve the early detection of cervical cancers.
Methods
CASE SELECTION
- The number of cervical cancers occurring in California was based on new cases of invasive cervical cancers diagnosed among California women aged 20 years and older between January 1, 2009 and December 31, 2013 and reported to CCR as of December 2015.
- This analysis was based on 6,710 incidents or new cases.
GEOGRAPHIC UNITS OF ANALYSIS (E.G. COMMUNITIES)
- The California Office of Statewide Health Planning and Development (OSHPD) has defined 542 Medical Service Study Areas (MSSAs) in California, which are groups of census tracts that make up “rational service areas” for primary health care and are used to identify medically underserved areas.
- All cases were geocoded to a census tract based on the county and street address at time of diagnosis.
- An MSSA code was assigned to each case based upon its census tract.
- OSHPD defines Primary Care Shortage Areas (PCSAs) as areas “having a shortage of health care providers on the basis of availability of primary care physicians.“2
- Qualifying MSSAs are designated as a PCSA based on high population to primary care physicians and lack of access to health care in surrounding areas.
DEFINITION OF ADVANCED STAGE
- Using Surveillance Epidemiology and End Results (SEER) summary stage criteria, cases were classified as early stage (in situ and localized) or advanced stage (regional, distant, or unknown stage). For more detailed information on SEER summary stage criteria go to www.seer.cancer.gov.3
COMPARISON GROUP
The comparison group selected was non-Hispanic white persons residing in high socioeconomic status (SES) neighborhoods. (A person’s SES status was ascertained using census indicators of income, employment, and education for the census block group or tract of residence at diagnosis). Non-Hispanic white persons in high SES neighborhoods were chosen as the comparison group because they had the lowest proportion of advanced disease (51 percent) compared to other race/ethnicity and income groups.
ANALYSIS
- The proportion of cervical cancers diagnosed at advanced stage in each MSSA was compared to the proportion of cervical cancers diagnosed at advanced stage in the comparison group. Differences in the sex and age distributions of the two groups were taken into consideration.
- For mapping, communities with a significantly higher proportion of advanced stage cervical cancer cases were divided into three groups: those where 75 percent or more of all cervical cancer cases were diagnosed at advanced stage, those where 70-74 percent were diagnosed at advanced stage, and 53-69 percent were diagnosed at advanced stage.
- Percentages of advanced stage cervical cancers were only mapped in MSSAs that had at least 15 cervical cancers cases diagnosed among women aged 20 years and older during the study period.
Results
The proportion of cervical cancer cases diagnosed at advanced stage was significantly elevated in 95 of the 542 MSSAs. Of those, ten MSSAs had 75 percent or more of all cervical cancers cases diagnosed at advanced stage, eight MSSAs had 70-74 percent of all cervical cancers cases diagnosed at advanced stage and 77 MSSAs had 53-69 percent of all cervical cancers cases diagnosed at advanced stage. In 137 MSSAs the proportion of cervical cancer cases diagnosed at advanced stage was not significantly different than the comparison group. Results were not calculated for 310 MSSAs where less than 15 cervical cancer cases were reported over the five-year period.
Conclusion
Geocoded registry data have been mapped to show communities with an excess of cervical cancer cases diagnosed at advanced stage. These maps are now available on the CCR website. Each map shows the MSSAs within the county and the percentage of advanced stage cervical cancers in the MSSAs. Accompanying each map is a table that details the study results and the demographic information for each MSSA. Below is a summary table displaying the MSSAs with statistically higher proportions of advanced stage cervical cancers.
Summary of MSSAs with Statistically Significantly* Higher Proportions of Advanced Stage Cervical Cancers, 2009-2013
Data: Cervical Cancer: Percent Diagnosed Advanced Stage and Proportional Incidence Ratios for Medical Study Service Areas within California Counties, 2009-2013
GIS Maps: Advanced Stage Cervical Cancer in California County Communities, 2009-2013
References
- California Behavioral Risk Factor Surveillance Survey, 2013. California Department of Public Health.
- Office of Statewide Health Planning and Development. Healthcare Workforce Development Division: Dental Health Professional Shortage Area (http://www.oshpd.ca.gov/HWDD/DHPSA.html).
- Surveillance, Epidemiology, and End Results Program. National Cancer Institute.
