New report: Incidence of breast cancer much higher than expected
Breast cancer rates in Flower Mound are 22 percent higher than expected, according to a new report from the Texas Department of State Health Services released Wednesday.
The state’s new report, which considers cancer data from 2002 to 2011, found women’s breast cancer rates higher than expected in two Flower Mound ZIP codes, 75022 and 75028. The previous report used data from 1998 to 2007 and found higher rates only in 75028.
The department revisited its 2010 report on Flower Mound after it was heavily criticized for its methods last year. An independent review of the cancer data, published as part of a fuller review in an environmental law journal, found problems with the state’s analysis.
The new report also considered other cancers, including childhood cancers, in the two ZIP codes. The data showed certain rates of leukemia higher than expected, but officials could not rule out that those rates were higher simply by chance.
Flower Mound Mayor Tom Hayden said he was briefed on the revised report Wednesday morning. Hayden remains concerned about breast cancer rates among younger women in Flower Mound and how it might compare statewide, but that information was not in the report.
“They said they would get that information for me,” Hayden said.
In the previous report, state officials began the executive summary by characterizing the breast cancer rate increase as a “slight elevation” that was “consistent with the population growth in the area.”
Later on in the same document, epidemiologists wrote that breast cancer rates were higher, and by a statistically significant amount, in the 75028 ZIP code.
The previous report had found that 183 women were diagnosed with breast cancer from 1998 to 2007, a rate 40 percent higher than expected.
The new report found statistically significant higher breast cancer rates in both the 75028 and 75022 ZIP codes.
In all, 369 women were diagnosed with breast cancer from 2002 to 2011. The rate is 22 percent higher than expected.
In her paper published in the Virginia Environmental Law Journal, University of Texas law professor Rachael Rawlins criticized the state’s previous report for using a 99 percent confidence interval. Researchers more commonly use a 95 percent interval, she said.
A confidence interval is a special math calculation that helps eliminate the possibility that an increase came by chance. In a small area with a low population, such as that of a single ZIP code, one or two new cancer cases can occur simply by chance and affect rate calculations for that area.
But by using a stricter confidence interval in its analysis, the state also can reach a false negative, Rawlins said. In other words, state officials risk not identifying a public health concern.
The state’s new analysis downplayed the connection between cancer rates and environmental exposure, even though that was the impetus for the work.
Cancer victims, their families and other Flower Mound residents have been concerned for several years about benzene and other carcinogens that could have come from the Barnett Shale boom, which has brought natural gas production into neighborhoods.
The new report acknowledges those concerns, but instead points to research that says cancer is often caused by lifestyle choices, such as smoking and obesity.
In a study of health data from 2006 to 2012, the Robert Wood Johnson Foundation estimated that approximately 10 percent of Denton County residents smoked. The same study estimated about 17 percent of Texans smoked, a little less than the estimated rate of 18 percent nationwide.
State health officials estimate that about 33 percent of residents in the Dallas-Fort Worth area are at risk of obesity.
Janet Ackerman, a researcher at the Silent Spring Institute, said community concerns about environmental factors are understandable, particularly when it comes to breast cancer.
She co-authored a paper published in May in Environmental Health Perspectives that identified 17 types of chemicals that should be targeted for study in relation to breast cancer.
“There is a growing body of evidence that a lot of chemicals in the environment that have been poorly studied could have an effect,” Ackerman said.
She pointed to new work from the federal Interagency Breast Cancer and Environmental Research Coordinating Committee and the Institutes of Medicine that showed the shift in research priorities.
The IOM report, in particular, identified three common air pollutants — benzene, ethylene oxide and 1,3 butadiene — as chemicals of concern when it comes to breast cancer, Ackerman said.
In a press release, Flower Mound officials called their local air monitoring program of Barnett Shale operators “effective and beneficial.”
Town inspectors have been able to find minor leaks and other operational items that are quickly addressed by operators, officials said.
State officials said they would continue to monitor cancer rates in Flower Mound.
PEGGY HEINKEL-WOLFE can be reached at 940-566-6881 and via Twitter at @phwolfeDRC.