- Elizabeth Larson
- Posted On
Study pinpoints new areas of concern in state for elevated breast cancer rates
LAKE COUNTY, Calif. – A new study has identified several areas in California previously not known to have invasive breast cancer rates substantially higher than the state average, while Lake County’s rate appears low compared to many other parts of the state.
The Public Health Institute’s California Breast Cancer Mapping Project found four new “areas of concern” encompassing sections of Ventura, Los Angeles, Riverside and Orange counties.
In addition, the research found that parts of the north and south Bay Area – including portions of Sonoma, Marin, Napa, Solano, Contra Costa, Alameda, Santa Clara and San Mateo counties – showed elevated rates for the disease.
The California Breast Cancer Mapping Project developed and used a protocol to map breast cancer rates within and across county boundaries and by using data obtained from the California Cancer Registry by census tract.
Researchers said that breast cancer surveillance traditionally has relied on aggregate county-level data. That method of surveillance had not identified the new focus areas, which span sections of multiple counties.
“Breast cancer doesn’t know geographic boundaries and this study shows that mapping breast cancer rates by census tract is a useful and important supplement to county-level surveillance, which is still essential,” said Eric Roberts, MD, PhD, principal investigator of the CBCMP. “We found that the specific communities most impacted by breast cancer can fall within or across counties. By identifying these communities we can more efficiently and effectively direct resources to them.”
The new methodology pointed to rates in the newly identified areas of concern that were 10 to 20 percent higher than the state average between 2000-08, with 2008 being the most recent data available when the study began, the project reported.
Researchers analyzed sociodemographic factors of women with breast cancer in the four areas of concern.
The findings showed that white women have an elevated risk of having the disease, a pattern that already had been identified in previous research.
They also found that women diagnosed with invasive breast cancer in the Ventura/Los Angeles area of concern had less private insurance compared to the other areas of concern and the state overall.
Here in Lake County, the new mapping did not find above-average incidences, which matches other studies of breast cancer rates.
Both the California Cancer Registry and the California Department of Public Health’s 2012 Health Status Profile for Lake County showed comparatively low rates for the disease when compared with other types of cancers.
From 2005 to 2009, Lake County had an age-adjusted invasive breast cancer rate of 55.46 people per 100,000, the fifth-lowest rate in the state, according to California Cancer Registry statistics. The state average was 66.07 incidences per 100,000.
Lake County Public Health Officer Dr. Karen Tait said Lake County’s breast cancer incidence rate is actually low. However, she said mortality rates are not as good.
She pointed to the county health status profile’s findings that Lake’s age-adjusted death rate for breast cancer was 21.7, slightly above the national objective of 21.3 and the state rate of 20.7.
She said the higher mortality rate may have to do with virulence of the disease and access to treatment, the latter being influenced by socioeconomic issues.
Tait also pointed out that every one of Lake County’s high cancer rates is worsened by smoking. “And people just don’t realize that.”
The new research, while meant to map areas of concern, wasn’t meant to determine the causes of breast cancer rates or detect specific environmental triggers, according to the report.
While the role that environmental pollutants play in breast cancer is of concern, the study’s authors said research shows that cancer often does not develop until decades after these exposures take place.
The maps are based on women live when they were diagnosed; the research does not include where they lived previously or what pollutant exposures they may have experienced.
Researchers hope the new protocol will be put to good use.
“The CBCMP mapping protocol is a very useful tool to enhance surveillance of breast cancer, and possibly other cancers, at the local level,” said Roberts. “We look forward to exploring how it can be more widely utilized by public agencies and other stakeholders.”
The project’s full report is available at http://cehtp.org/resources/breast_cancer_mapping/ or can be viewed below.
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California Breast Cancer Mapping Project Final Report November 2012