> Emerging Areas in Chemotherapy, Hormone Therapy and Targeted Therapy
Research is ongoing to improve chemotherapy, hormone therapy and targeted therapy for breast cancer. New therapies are being studied in clinical trials. The results of these studies will decide whether these therapies become part of standard care. After discussing the benefits and risks with your health care provider, we strongly encourage you to consider joining clinical trials of new therapies.
Learn more about joining a clinical trial.
This section discusses emerging areas of research for early breast cancer treatments. Learn about promising, new treatments for metastatic breast cancer.
Gene expression profiling
Gene expression profiling is a promising tool for helping guide breast cancer treatment. These tests do not show a genetic profile of personal traits, but rather a profile of the tumor. The genetic profiles of tumors help predict which cancers may be more aggressive and more likely to recur [25]. Tumors with gene profiles showing a high risk of recurrence may be more likely to respond to chemotherapy than tumors with gene profiles showing a low risk of recurrence.
At this time, the gene profiling test OncotypeDx can be used to help make chemotherapy treatment decisions in people with estrogen receptor-positive cancers who are on hormone therapy [26-27]. Other genetic profiling tests and their use in guiding treatment plans are still under study [28-29].
Learn more about OncotypeDx.
Mammaprint
Mammaprint is a gene expression profiling tool for lymph node-negative breast cancer (although can be used for either hormone receptor-positive or hormone receptor-negative tumors). Mammaprint is still mostly limited to the research setting in the United States because it requires special preparation of the biopsy tissue. It is more commonly used in Europe.
Subtypes of breast cancer
Molecular and genetic differences in breast cancers may be useful in guiding the development of new targeted therapies. One area of study divides breast cancers into four molecular subtypes: luminal A, luminal B, triple negative/basal-like and HER2 type.
At this time, subtypes are not used in clinical settings. They are used only in the context of a research study.
Learn more about subtypes of breast cancer.
CYP2D6 and tamoxifen
CYP2D6 is an enzyme that affects how the body metabolizes (breaks down and uses) certain medicines, including tamoxifen. Some people have a genetic variation (a certain form of the CYP2D6 gene) that results in little or no CYP2D6 function. Others have a variation leading to higher than normal CYP2D6 function.
Several studies have looked at whether variations in the CYP2D6 gene might affect how well tamoxifen works in postmenopausal women with breast cancer. Study findings to date are mixed. Some small studies found that women with gene variations related to less CYP2D6 function had a higher risk of recurrence than women with genes related to normal or high CYP2D6 function [30-32]. However, the largest study to date showed no difference in the effect of tamoxifen by CYP2D6 gene variation [33]. More research is needed to understand whether there is a role for CYP2D6 gene variation in tamoxifen therapy.
Certain medicines can interfere with CYP2D6 function and should be avoided while taking tamoxifen [30]. For example, some antidepressants, such as fluoxetine (Prozac) and paroxetine (Paxil), can interact with CYP2D6 and may affect how tamoxifen works in the body [30]. If you are considering taking tamoxifen, talk to your health care provider about potential drug interactions.
Learn more about tamoxifen.
Bisphosphonates
Bone-strengthening therapy using bisphosphonates is a standard treatment for women with bone metastases (more) [34-35]. Bisphosphonates are also used to help prevent bone loss (osteoporosis) in breast cancer survivors and cancer-free women [35].
Early findings from a randomized clinical trial showed the bisphosphonate zoledronate (Zometa) increased disease-free survival among some premenopausal women [36]. However, a recent, larger study found no survival benefit [167]. This study also showed bisphosphonate use increased the risk of osteonecrosis of the jaw, a serious jaw bone disorder [167]. Bisphosphonate use among breast cancer survivors is still under active study.
Though rare, bisphosphonates may increase the risk of osteonecrosis of the jaw, a serious jaw bone disorder. It is important to have a dental exam prior to starting treatment with bisphosphonates [37].
Read our perspective on bisphosphonates and breast cancer survival.
PARP inhibitors
Poly(ADP-ribose) polymerase (PARP) inhibitors are a new class of drugs under study for many types of cancer, including breast cancer. PARP is an enzyme involved in DNA repair. Some chemotherapy drugs damage DNA. Adding a PARP inhibitor to some chemotherapy plans may lower the chances that cancer cells become resistant to the chemotherapy. This is most often a problem for those with metastatic breast cancer.
PARP inhibitors are under study for the treatment of breast cancers related to gene mutations such as BRCA1 and BRCA2 as well as triple negative breast cancers [38].
At this time, data on PARP inhibitors and breast cancer are limited and are not conclusive. Although results look promising, these drugs are in the early stages of study and are only offered in clinical trials.
Read comments on the potential uses of PARP inhibitors from our Chief Scientific Advisor, Dr. Eric Winer.
Other drugs
Other drugs, including capecitabine (Xeloda), are under study for the treatment of early breast cancer. Capecitabine is a chemotherapy drug used to treat metastatic breast cancer. It is now being studied for use in the treatment of early breast cancer in both the neoadjuvant and adjuvant setting [39-40]. Findings to date are mixed.
High-dose chemotherapy/bone marrow transplant
High-dose chemotherapy (sometimes called bone marrow transplant) was an experimental therapy that used high doses of drugs to try and kill a large number of cancer cells. It was thought that the more intense chemotherapy might kill cancer cells better than standard chemotherapy.
Despite early hopes for this approach, randomized clinical trials in the 1990s showed that high-dose chemotherapy was no more effective than standard dose chemotherapy [41-44]. High-dose chemotherapy also had more serious side effects, such as liver, lung and bone marrow problems and was found to be fatal in about six percent of people [44].
High-dose chemotherapy is not a part of standard treatment of breast cancer.
Our commitment to research
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At Susan G. Komen for the Cure®, we are committed to ending breast cancer forever by energizing science to find the cures and ensuring quality care for all people, everywhere. Our global research and grants programs are essential driving forces for achieving this mission. A Komen for the Cure grant has touched every major breast cancer breakthrough and major scientists of the past 29 years—including three Nobel Prize winners. Funding for discoveries in genetics and biology has evolved into personalized, less invasive treatments for what was once a “one-treatment-fits-all” disease. Learn more about the exciting research we are funding.
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Updated 01/20/12
