Breast cancer remains the most common cancer among women. In the past two decades, breast cancer treatment has become personalized. This is possible due to the subtype of breast cancer. Breast cancer has been subtyped based on receptors on breast cancer cells. The most clinically important receptors-those with targeted therapies-are the estrogen and progesterone receptors and the human epidermal growth factor receptor 2 (HER2). Cancers with estrogen and progesterone receptors are called hormone receptor (HR) positive cancers.
The development of hormone therapy for HR-positive breast cancer means that some women can give up chemotherapy if the risks of receiving chemotherapy outweigh the benefits. The development of genomic assays (tests that analyze genes expressed in cancer) provides a way to help doctors and women determine who will get the most benefit from chemotherapy.
How can genomic testing help personalize breast cancer treatment?
Increasing knowledge about breast cancer has led to the development of personalized therapy. In addition to understanding the type and stage of cancer, genomic testing has further refined the way we assess the risk of breast cancer recurrence. One genomic test is Oncotype Dx, which is a useful tool that can help predict the likelihood of benefit from chemotherapy and the risk of recurrence of invasive breast cancer.
Not all women need chemotherapy, but for some women, hormone therapy alone is not enough. Oncotype Dx analyzes the expression of 21 genes in HR-positive and HER2-negative breast cancer, and assigns a recurrence score (RS) based on the risk of recurrence. The Oncotype Dx test divides women into three categories: low, moderate or moderate, and high risk of recurrence.Women with lower scores do not need chemotherapy, and hormone therapy has the greatest benefit, while women with higher recurrence scores benefit the most from chemotherapy In addition to Hormone therapy.
New research can help women make decisions about chemotherapy
Until recently, it was not clear how much women who received a moderate risk score from chemotherapy would benefit from it. A randomized clinical controlled trial, Tailor Rx trial, Answered this question. The trial randomly divided women with negative lymph nodes (cancer that has not spread to the lymph nodes), HR-positive, and HER2-negative breast cancer into women with a medium risk score outside hormone therapy or hormone therapy. The results showed that most women with a moderate risk of invasive cancer did not get any additional benefits through chemotherapy. but, Have done Premenopausal women under the age of 50 can benefit from chemotherapy.
Although the results of the Tailor Rx trial changed practice, it did raise questions about the benefits of chemotherapy for women with HR-positive, HER2-negative breast cancer that has spread to the lymph nodes. The trial version of RxPonder answers this question.
The RxPonder trial randomly divided 5,015 women with stage II/III HR-positive, HER2-negative breast cancer, one to three positive lymph nodes, and intermediate RS (≤25). Patients were randomly assigned to receive hormonal therapy alone or to receive hormonal therapy with chemotherapy. The main purpose of this study was to determine how many women did not have recurrent invasive breast cancer at the time of follow-up.
There are many ways to compare the women in the study, but the main characteristics chosen for comparison are: menopausal status, RS, and type of axillary surgery received. At a median follow-up of 5.1 years, there was no association between chemotherapy benefit for the entire population and RS values between 0 and 25. However, there is a correlation between the benefits of chemotherapy and menopausal status. The trial provided evidence that even women with lymph node cancer can avoid chemotherapy if their RS is low or moderate.
Premenopausal women respond better to hormone therapy and chemotherapy
Among the women who signed up RxPonder In the trial, 3,350 patients were postmenopausal and 1,665 were premenopausal. Further analysis of menopausal status revealed that there was no difference in the five-year survival rate of postmenopausal women who received hormone therapy only and those who received hormone therapy.
However, for premenopausal women, the risk of invasive disease is reduced by 46%. For this subgroup of women, the five-year noninvasive disease-free survival rate of women receiving hormone therapy and chemotherapy is 94.2%, compared with 89% of women receiving hormone therapy only. Premenopausal women who receive both chemotherapy and hormone therapy have an additional benefit of about 5%.It is not clear whether the survival benefit of premenopausal women is mainly due to the effects of chemotherapy or indirectly due to ovarian suppression caused by chemotherapy
What does this mean for breast cancer treatment decisions?
Breast cancer treatment has truly become personalized. Knowing your cancer stage has always been important, but now it’s also important to know your cancer type. Armed with this information, women can have an informed discussion with oncologists about the risks and benefits of chemotherapy.
If you are a premenopausal woman with HR-positive, lymph node-positive breast cancer, chemotherapy and hormone therapy may give you the greatest opportunity to reduce your risk of cancer. However, for women with HR-positive breast cancer after menopause, chemotherapy may not bring many therapeutic benefits to hormone therapy and may affect your quality of life. Research such as TailorRx and RxPonder trials provide more information to help you make an informed decision.