Study: A step in the development of a new breast cancer risk assessment tool for Hispanic women

IN DEPTH REVIEW OF RESEARCH

Study background:

The National Cancer Institute’s Breast Cancer Risk Assessment Tool (BCRAT) is currently used to predict breast cancer risk in women who do not have mutations in BRCA or other genes associated with hereditary breast cancer. However, for Hispanic women, the BCRAT develops estimates of invasive breast cancer risk by combining Hispanic age-specific incidence rates with relative risks from white women. A previous research study reported that BCRAT underestimates Hispanic women’s breast cancer risk by 18%.

Matthew Banegas and colleagues from Kaiser Permanente Northwest published work in the Journal of the National Cancer Institute describing their new breast cancer risk estimation tool developed specifically for Hispanic women.

Researchers of this study wanted to:

Develop a risk assessment tool for calculating breast cancer risk specifically for Hispanic women.

Population(s) looked at in the study:

The researchers used data from the following sources for their model:

The San Francisco Bay Area Breast Cancer Study (SFBCS) included Hispanic women, ages 35-79 who were diagnosed with a first primary invasive breast cancer between 1995 and 2002. The study included information from 1,086 women with invasive breast cancer (533 were US-born while 553 were foreign-born) and 1,411 control participants (464 were US-born while 947 were foreign-born).
The California Cancer Registry (CCR) and SEER program were used for additional incidence and mortality information.

The risk estimates from the researchers’ new model were compared to the estimates from the National Cancer Institute’s Breast Cancer Risk Assessment Tool (BCRAT).

Results

1. The researchers developed the Hispanic Risk Model (HRM) to estimate breast cancer risk that only uses data from Hispanic women.
   • The risk factors incorporated in this model included age at first full-term pregnancy and family history of breast cancer in first-degree female relatives.
   • Breast cancer risk calculated by the HRM was lower than the risk calculated by the National Cancer Institute’s Breast Cancer Risk Assessment Tool (BCRAT) for Hispanic women who were born in the U.S., but it was higher for foreign-born Hispanic women.

Limitations:

The researchers’ risk tool only used data from Hispanic females residing in California, so it is unknown how the tool will perform with other populations. And while different Hispanic subgroups exist in the United States, including women with different countries of origin as well as different races, the researchers categorized all Hispanic women into one group.  Additionally, the San Francisco Bay Area Breast Cancer Study (SFBCS) group included only women who were 35-79 years old.

In addition, not all risk factors were accounted for in the researchers’ model, such as breast density and genetic variants.  Additional factors could refine the model so that it accurately predicts breast cancer risk in both Hispanic women born in the United States and those born overseas. Finally, the researchers wrote that “The HRM, like the BCRAT, should not be used for certain women. It will probably underestimate breast cancer risk in Hispanic women with a personal history of breast cancer…, in women carrying breast cancer-causing mutations, and in women who received therapeutic radiation doses to the breast at a young age, such as for treatment of Hodgkin’s lymphoma.”

Conclusions:

Researchers have developed a new risk assessment tool to calculate breast cancer risk in Hispanic women who do carry gene mutations associated with hereditary breast cancer. Like the currently used BCRAT model, this model looks at risk for invasive breast cancer (stages I-IV) and not ductal carcinoma in situ (DCIS or stage 0).  However, more work needs to be done to validate this new model. In the meantime, Hispanic women should discuss any concerns they have with their health care providers.

Posted 2/7/17

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