Emerging research and possible new treatments for breast cancer
While about 1 in 8 American women will be diagnosed with breast cancer sometime in their lifetime, fortunately the rate of women dying from the disease has been declining since about 1989. This decrease is believed to be the result of earlier detection through screening and increased awareness, as well as improved treatments. New research is being conducted around the world and these findings are opening the door to advanced diagnostic procedures, more effective medications and combinations of medications, treatments that target the cancer and ways to detect and track cancer cells throughout the body. We don’t yet have the magic cure or foolproof vaccine that can stop breast cancer in its tracks, but there is good news about what is on the horizon.
What we are learning about the causes of breast cancer
• Studies continue to uncover lifestyle factors, such as exercise, weight gain or loss and diet, as well as habits such as smoking and alcohol consumption that can affect a woman’s risk of breast cancer.
• Studies on the best use of genetic testing for BRCA1 and BRCA2 mutations continue at a rapid pace. Scientists are also exploring how common gene variations may affect breast cancer risk.
• Potential causes of breast cancer in the environment have also received more attention in recent years. While much of the science on this topic is still in its earliest stages, this is an area of active research.
• A large, long-term study funded by the National Institute of Environmental Health Sciences (NIEHS) known as the Sister Study, has enrolled 50,000 women who have sisters with breast cancer. This study will follow these women for at least 10 years and collect information about genes, lifestyle, and environmental factors that may cause breast cancer.
Chemoprevention – Medicines that may help prevent breast cancer
Fenretinide, a retinoid (a drug related to vitamin A), is being studied as a way to reduce the risk of breast cancer. In a small study, this drug reduced breast cancer risk as much as tamoxifen.
Other drugs, such as aromatase inhibitors, are also being studied to reduce the risk of breast cancer.
Help in making treatment decisions about DCIS
In some women, ductal carcinoma – invasive and in situ (DCIS), a breast cancer that forms in the milk ducts – turns into invasive breast cancer or contains invasive cancer. In other women, the cells remain localized within the ducts. When these cells don’t become invasive DCIS is not life-threatening. However, the uncertainty about how DCIS will behave makes it difficult for women to make decisions about what treatment to have, if any.
Researchers are studying the use of computers and statistical methods to estimate the odds that DCIS will become invasive, and decision aids to help a woman decide which factors (such as survival, preventing recurrence, and side effects) she considers most important in choosing a treatment.
New laboratory and imaging tests may help identify and track cancer cells.
• Researchers have found that in many women with breast cancer, cells may break away from the tumor and enter the blood. These circulating tumor cells can be detected with sensitive lab tests which may help predict which patients may go on to have their cancer come back, and potentially may help determine if breast cancer treatments are working.
• Scintimammography (molecular breast imaging), uses a slightly radioactive tracer called technetium sestamibi which is injected into a vein. The tracer attaches to breast cancer cells and is detected by a special camera. Although not a replacement for the mammogram, this technique is being studied to see if it will be useful in finding breast cancers, such as in the dense breasts of younger women. Some early studies have suggested that it may be almost as accurate as more expensive MRI scans.
• Tomosynthesis (3-D mammography) is basically an extension of a digital mammogram. The breast is compressed once and a machine takes many low-dose x-rays as it moves over the breast. These images are combined into a 3-dimensional picture. Although it uses more radiation than most standard 2-view mammograms, it may have the advantage of seeing problem areas more clearly, possibly finding more cancers. More studies comparing breast tomosynthesis to standard 2 view mammograms are needed.
Treatments that are showing promise
>> Oncoplastic surgery – Breast-conserving surgery (lumpectomy or partial mastectomy) can often be used for early-stage breast cancers. But in some women, it can result in breasts of different sizes and/or shapes. For larger tumors, it might not even be possible, and a mastectomy might be needed instead. Some doctors address this problem by combining cancer surgery and plastic surgery techniques, known as oncoplastic surgery. This typically involves reshaping the breast at the time of the initial surgery, and may mean operating on the other breast as well to make them more symmetrical.
>> New chemotherapy drugs – Advanced breast cancers are often hard to treat, so researchers are always looking for newer drugs.
A drug class has been developed that targets cancers caused by BRCA mutations. This class of drugs, called PARP, has shown promise in clinical trials treating breast, ovarian, and prostate cancers that had spread and were resistant to other treatments. Further studies are being done to see if this drug can help patients without BRCA mutations.
>> Targeted therapies – A group of newer drugs has been created specifically to take advantage of gene changes in cells that cause cancer. A number of drugs currently are in use that target HER2 including trastuzumab (Herceptin), pertuzumab (Perjeta), ado-trastuzumab emtansine (Kadcyla), and lapatinib (Tykerb). Other drugs are being developed and tested.
>> Anti-angiogenesis drugs – For cancers to grow, blood vessels must develop to nourish the cancer cells. This process is called angiogenesis. Looking at angiogenesis in breast cancer specimens can help predict prognosis. Some studies have found that breast cancers surrounded by many new, small blood vessels are likely to be more aggressive.
Bevacizumab (Avastin) is an example of anti-angiogenesis drug. Although bevacizumab turned out to not be very helpful in the treatment of advanced breast cancer, this approach still may prove useful in other cancers. Several other anti-angiogenesis drugs are being tested in clinical trials.
>> Vitamin D – A recent study found that women with early-stage breast cancer who were vitamin D deficient were more likely to have their cancer recur in a distant part of the body and had a poorer outlook. More research is needed to confirm this finding. Still, you might want to talk to your doctor about testing your vitamin D level to see if it is in the healthy range.
>> Other targeted drugs – Everolimus (Afinitor) is a targeted therapy drug that seems to help hormone therapy drugs work better. It has been approved to be given with exemestane (Aromasin) to treat advanced hormone receptor-positive breast cancer in post-menopausal women. It has also been studied with other hormone therapy drugs and for treatment of earlier stage breast cancer. In one study, letrozole plus everolimus worked better than letrozole alone in shrinking breast tumors before surgery. It also seemed to help in treating advanced hormone receptor-positive breast cancer when added to tamoxifen. Everolimus is also being studied in combination with chemotherapy and the targeted drug trastuzumab. Other drugs like everolimus are also being studied.
Bisphosphonates are used to help strengthen and reduce the risk of fractures in bones that have been weakened by metastatic breast cancer. Examples include pamidronate (Aredia) and zoledronic acid (Zometa). Some studies have suggested that zoledronic acid may help other systemic therapies, like hormone treatment and chemo work better. In one study of women being treated with chemo before surgery, tumors in the women getting zoledronic acid with chemo shrank more than those in the women treated with chemo alone. Other studies have looked at the effect of giving zoledronic acid with other adjuvant treatment (like chemo or hormone therapy). So far, the results have been mixed. Some studies have shown that this approach helped lower the risk of the cancer coming back, but others did not.
Denosumab (Xgeva, Prolia) can also be used to help strengthen and reduce the risk of fractures in bones that have been weakened by metastatic breast cancer. It is being studied to see if it can help adjuvant treatments work better.
Source: American Cancer Society