How cutting-edge RNA-based gene expression testing can help tailor treatments and improve outcomes for women with early-stage breast cancer


Posted: October 31, 2022 | Word Count: 1,105

One of the best tools available to personalize treatments to help improve outcomes for women with breast cancer is gene expression profiling. The ability to determine highly specific information about an individual tumor by analyzing how the genes express themselves differently provides an opportunity to identify the right treatment for the right patient at the right time. Gene expression profiling gives unprecedented levels of information to help a woman and her doctor make the most informed decision about her treatment plan.

However, certain genomic tests have blind spots that can lead to undertreatment. A recent publication has shown a 21-gene assay to be less accurate in providing information for Black women, a group at higher risk than most. According to the Breast Cancer Research Foundation, while breast cancer incidence rates among Black and white women are similar, their mortality rates are markedly different — 41% higher for Black women. And among women under 50, this disparity is even greater: the mortality rate of young Black women from breast cancer is double that of young white women.

Disparities in cancer care for Black women are found in all aspects of a patient’s experience — including access and representation in clinical trials, treatment, care center access and testing. While there are many complex socioeconomic factors that contribute to these racial disparities, differences in biology could play an important role. Black women are disproportionally affected by more aggressive subtypes of cancer, according to the Breast Cancer Research Foundation. They often can benefit from more aggressive treatments or targeted therapies, so it is critical Black women and their providers have the addition of biological insights into the tumor when making treatment decisions.

Genomic insights should be accurate for everyone

Fortunately, there are gene expression tests that have more consistent results in Black women than others on the market. One of them, the MammaPrint® test, analyzes 70 of the most important genes associated with the risk of distant metastasis — in other words, the risk the cancer will spread to distant sites. With results typically available in six days or less, MammaPrint enables quicker, more comprehensive biological insights into the tumor to enable informed decisions on pre- and post-operative treatments which can easily be ordered on a biopsy or surgical sample. It is critical healthcare providers and their patients make correct treatment decisions at the time of diagnosis so they have the best chance of cure. If the best treatment for that unique tumor isn’t selected, and the patient develops metastatic disease, it then becomes an incurable disease which will shorten the life of that woman.

It is so important to integrate all relevant information on that individual woman’s breast cancer, including genomic information into the biology of her tumor, when selecting the appropriate therapy to maximize cure while maintaining quality of life. The hardest dilemma for providers is finding the right balance between treatments aimed at maximizing cure, with the least toxic options to achieve that cure. In a recent landmark trial, nearly half of the women that appeared to have high-risk tumors based on conventional clinical assessments were actually found to have a MammaPrint Low Risk result, and were able to safely forgo chemotherapy in favor of other less toxic treatment options without compromising their chances for survival.

Another innovative test, BluePrint®, that can be ordered with MammaPrint, examines 80 genes to identify the molecular subtype of an individual tumor. The tumor is then accurately classified as one of three subtypes, revealing valuable information about its behavior, what drives its growth, long-term prognosis, and response to therapy. When the test is ordered on the biopsy tissue, results are typically ready in time for a patient’s pre-operative consultation, so the care team has the right insights for the right treatment at the right time. In a recent study, 22% of patients were further classified from their original subtype based on clinical or pathological factors into a molecular subtype — identifying an opportunity to tailor appropriate treatments to that patient’s specific molecular profile – which they otherwise would not have known — and predict likelihood of treatment response.

“Having detailed information about the biology of a woman’s cancer quickly helps pinpoint the most effective and timely treatment, and by ordering MammaPrint and BluePrint, a physician will be more confident in selecting the treatment option best suited for her individual tumor, no matter her race,” said acclaimed breast surgeon Dr. Princess Thomas Williams from the Breast Care Specialists of Carolina. “These tests provide the most specific information we can currently get to help women of all backgrounds receive the best possible health outcomes, and it’s important to remember not all genomic tests are the same. Using the most comprehensive one can ensure the results are consistent regardless of race and ethnicity so you can rely on the insights when making critical treatment decisions.”

Because the MammaPrint and BluePrint tests analyze a total of 150 genes in the tumor — more than any other RNA gene expression test — they are able to capture the diversity of pathways driving tumor metastasis and tumor growth. In fact, the BluePrint test is the only test capable of identifying the hormone-receptor-positive cancer tumors that will actually clinically behave like triple negative breast cancers which are some of the aggressive tumors necessitating more aggressive therapy to ensure strong outcomes. Studies have shown Black women had more than double the chance of having that higher risk ER+/Basal type of tumor than white women. Only BluePrint can identify these higher risk Black women who otherwise could have been undertreated had they not had their gene expression profile.

The need for more diverse clinical testing

Beyond the immediate need to ensure each woman with breast cancer has the information she needs to make timely decisions about treatment with her care team, there is also a need for genomic information that is representative of and effective for diverse patient groups. Black women comprise only 1-3% of clinical trial participants, despite being seven times more likely to die as result of breast cancer than white women.

It’s important to shine a light on these disparities, and more progress needs to be made to improve outcomes for Black women with breast cancer. It’s vital to recruit more Black women to participate in clinical trials so they are represented in the data being used to guide care. Improvements can start just days after diagnosis by giving Black women access to the best gene expression profiling of their tumor that they can rely on for their specific cancer.

To learn more and access resources on the right genomic test for you, visit agendia.com.

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