New therapies sought for triple-negative breast cancer

By Mayo Clinic News Network

Have you heard of triple negative breast cancer? It lacks the three main hormone receptors including estrogen receptor (ER), progesterone receptor (PR) and the human epidermal growth factor receptor (HER2).

Researchers have found that it's more common in younger women and in African-American women. It's also more commonly diagnosed in women who have BRCA positive breast cancer.

The approach to treating triple negative breast cancer is different because of the lack of the presence of hormone receptors. Hormonal therapies that are frequently given to treat hormone-receptor positive breast cancers, such as tamoxifen (which blocks the ER) and aromatase inhibitors (which reduces the production of estrogen), don't work for triple negative breast cancers.

Triple negative breast cancer is usually sensitive to chemotherapy. Neoadjuvant chemotherapy (chemotherapy given prior to surgery) is recommended to shrink the tumor prior to surgery. Survival rates improve greatly if it responds well to chemotherapy prior to surgery.

For some women, triple negative cancer doesn't respond well to chemotherapy -- this is where the challenge comes in for oncologists. If a tumor continues to grow even with chemotherapy treatments, new strategies are needed.

It's frequently treated with combination chemotherapies (anthracyclines and taxanes are common) along with surgery. Surgical options include lumpectomy with radiation or mastectomy (some women may receive chest wall radiation after a mastectomy). If the cancer returns, taxanes may be used again or other drugs that have been shown to be effective.

Xeloda (capecitabine) and platinum containing chemotherapies such as cisplatin and carboplatin can be highly effective. This is especially true for breast cancer tumors that have a mutation (such as BRCA mutations).

The theory is that these particular tumors are defective in the way in which they repair damaged DNA. Platinum containing drugs are DNA-damaging drugs and therefore may work better for women with BRCA mutated cancers.

Newer therapies include Ixempra (ixabepilone) and Halaven (eribulin). They target the cancer cell's ability to grow and divide. Additional studies will continue to look at the best way to target and treat triple negative breast cancer.

Researchers know that there are still many challenges to treating it as each person may have unique genetic and molecular features. Oncologists and researchers are discovering that combining therapies to target a variety of growth pathways may be the best approach.

For more information on clinical trials that are offered for triple negative breast cancer, visit, www.cancer.gov or www.breastcancertrials.org.

-- Sheryl M. Ness, R.N.

Source: http://www.mayoclinic.org/diseases-conditions/cancer/expert-blog/triple-negative-breast-cancer/bgp-20090306