Research into the causes, prevention, and treatment of breast cancer is going on in many medical centers throughout the world.

Causes of breast cancer

Studies continue to find lifestyle factors and habits that alter breast cancer risk. Some studies are looking at the effect of exercise, weight gain or loss, and diet on breast cancer risk. We are also learning more about how genes influence breast cancer. This should happen more quickly now that the human genome has been mapped out.

A large, long-term study is now going on to help find the causes of breast cancer. It is known as the Sister Study and it will follow 50,000 women whose sisters (not they themselves) have had breast cancer. Over 10 years, information will be gathered on many factors that might cause breast cancer. An offshoot of the Sister Study, the Two Sister Study, is designed to look at possible causes of early onset breast cancer. If you want to find out more about these studies, you can call 1-877-4-SISTER (1-877-474-7837) or visit the Web site at www.sisterstudy.org.

Chemoprevention

Studies have suggested that drugs like tamoxifen and raloxifene may lower breast cancer risk in women with certain breast cancer risk factors. But so far, many women don't want to take these drugs because they are concerned about possible side effects.

Newer studies are looking at whether aromatase inhibitors can reduce the risk of developing breast cancer in post-menopausal women. These drugs are already being used to help prevent breast cancer recurrences, but none of them are approved for reducing breast cancer risk at this time.

Fenretinide, a drug related to vitamin A, is also 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 are also being studied to reduce the risk of breast cancer. For more information, see our document, Medicines to Reduce Breast Cancer Risk.

New lab tests

Gene studies

One of the problems with early stage breast cancer is that doctors cannot always tell which women have a higher risk of cancer coming back after treatment. That is why almost every woman gets some sort of adjuvant treatment after surgery. To try to better decide out who will need adjuvant therapy, researchers have looked at many aspects of breast cancers.

In recent years, scientists have been able to link certain patterns of genes with more aggressive cancers -- those that tend to come back and spread to distant sites. Some lab tests based on these findings are already available, but doctors are still trying to figure out the best way to use them. Other tests are being developed, too.

Classifying breast cancer

Research on patterns of genes has also suggested some new ways of grouping breast cancers. The current types of breast cancer are based largely on how tumors look under a microscope. A newer system, based on molecular features, may be better able to predict outlook and response to some breast cancer treatments.

Tumor cells in the blood

Researchers have found that in many women with breast cancer, cells may break away from the tumor and enter the blood. These tumor cells can be found with sensitive lab tests. These tests are not yet ready for general use, but in the future they may be helpful in learning whether treatment like chemo is working-- or for finding cancer that has come back after treatment.

Newer imaging tests

Some newer imaging methods are being studied to see how they can be used to look at areas of change in the breast that might be cancer. You can find out more about these methods in our document, Mammograms and Other Breast Imaging Procedures.

Treatment

Newer types of mastectomy

Newer types of mastectomy that try to give better looking results after surgery are now being studied.

Nipple-sparing mastectomy: This is even newer approach is something like the skin-sparing mastectomy in that the nipple and areola are cut away when the breast tissue is removed. But here the nipple and darker skin around it (areola) are scraped clean of breast tissue and looked at by a pathologist. As long as there are no breast cancer cells found close to the nipple and areola, they are then reattached.

Further studies of these methods are needed to make sure they don't result in a higher risk of cancer starting or coming back.

Oncoplastic surgery

Sometimes after breast surgery the breasts can be different sizes or shapes. Some doctors are trying to address this problem by combining cancer surgery and plastic surgery. This is called oncoplastic surgery. It involves reshaping the breast at the time of the breast-conserving surgery, and may mean operating on the other breast as well to make them look more alike. This approach is still fairly new, and not all doctors are comfortable with it. The main concern is whether or not oncoplastic surgery might be more likely to leave tumor tissue behind.

Breast reconstruction surgery

Advances in re-attaching blood vessels (microvascular surgery) have led to improvements in breast reconstruction.

Research has shown that women who have breast implants used for breast reconstruction do not have any greater risk for immune system diseases than women who have not had this surgery. Also, breast implants have not been shown to increase the risk of the breast cancer coming back or of a new cancer forming. To learn more about the types of reconstructive surgery now available, see the American Cancer Society document, Breast Reconstruction After Mastectomy.

Radiation treatment

Doctors are comparing giving larger daily doses of radiation over fewer days to the standard radiation schedule. Studies have shown that giving radiation over 3 weeks seems to work about as well as the standard 5-week course. Other studies are looking at giving even larger daily doses over an even shorter time, such as a week.

For women who need radiation after lumpectomy, a method called APBI (accelerated partial breast irradiation) may offer an easier way to get it (as opposed to the standard daily radiation treatments that take many weeks to complete). There are several types of APBI now being studied. Large studies are going on to find out if these techniques work as well as standard radiation in helping to prevent cancer from coming back.

New chemo drugs

Because advanced breast cancers are often hard to treat, researchers are looking for newer, better drugs. A drug has been developed that targets cancers caused by BRCA mutations. It is called olaparib and it worked in treating breast, ovarian, and prostate cancers that had spread and that weren't helped by other treatments. Further studies are being done to see if this drug can help patients without BRCA mutations.

Targeted therapies

Targeted therapies are a group of newer drugs that take advantage of gene changes in cells that cause cancer. Two of these drugs, trastuzumab (Herceptin) and lapatinib (Tykerb), are being used to treat some breast cancers today. Newer studies are looking at using Tykerb instead of Herceptin for early-stage breast cancer. Other targeted therapies are also being tested.

Everolimus (Afinitor^®) is a new type of targeted therapy drug that has been approved to treat kidney cancer. In one study, letrozole plus everolimus worked better than letrozole alone in shrinking breast tumors before surgery. More studies using this drug are planned.

Angiogenesis

In order for cancers to grow, blood vessels must be made to feed the cancer cells. Some studies have found that breast cancers with many new, small blood vessels are likely to spread more quickly. New drugs are being made that may be useful in stopping breast cancer growth by keeping new blood vessels from forming. Some of these drugs are now being tested in clinical trials.

Bisphosphonates

Bisphosphonates are drugs that are used to help strengthen and reduce the risk of fractures in bones that have been weakened by metastatic breast cancer. More studies are needed to find out if bisphosphonates should become part of standard therapy for early breast cancer.

Vitamin D

A recent study found that women with early stage breast cancer who had low levels of vitamin D were more likely to have their cancer come back in a distant part of the body and had a poorer outlook. More research is needed to confirm this finding, and it is not yet clear if taking vitamin D supplements would be helpful. Still, you may want to talk to your doctor about testing your vitamin D level to see if it is in the healthy range.

Denosumab

When cancer spreads to the bone, it causes increased levels of a substance called RANKL, which is important in how bone is maintained. Higher RANKL levels cause cells called osteoclasts to destroy bone. A newer drug called denosumab acts against RANKL and can help protect bones. In early studies it seems to help even after bisphosphonates stop working. More studies are going on.

Last Medical Review: 09/29/2009
Last Revised: 09/29/2009