Advances in the treatment of triple-negative breast cancer
New form of therapy
The death rate from breast cancer in 1989 was 33.2 per 100,000 women, according to the American Cancer Society Flash forward to 2015 when the death rate plummeted 39 percent to 20.3. The improvement is largely attributed to increased awareness as well as advances in early detection and treatment. This improvement translates to an estimated fewer 322,660 deaths from breast cancer each year.
Generally, we speak of breast cancer as though it is one disease. Yet, there are several different types, and they are typically classified by the specific cells affected and whether or not it has spread to other parts of the body. One breast cancer ─ inflammatory breast cancer ─ doesn’t even start as a tumor, thereby escaping detection by mammogram.
The advances in treatments, however, do not apply across the board to all types of breast cancer. For instance, some tumors are affected by hormones in the blood. About 65 percent of breast cancers have receptors for both estrogen and progesterone, which can actually support the growth of breast cancer. In addition, cancer cells that have an excessive amount of a protein called HER2 tend to grow and spread more aggressively.
Fortunately, newer treatments ─ particularly hormone therapy and targeted drugs ─ are now available that increase the survival of women with these types of cancers.
For those with triple-negative breast cancer (TNBC), however, it’s a different story. The cells in this type of breast cancer lack hormone receptors and are lacking or low in the HER2 protein. Because of their characteristics, hormone therapy and drugs that target HER2 are not effective treatments. Chemotherapy is usually the standard treatment along with surgery and radiation. However, a large number of patients develop resistance to treatment within a few months.
TNBC is more common among black women and occurs at a younger age. It is more aggressive and more likely to spread and recur. While generally the five-year survival rate for breast cancer is 90 percent, the five-year survival rate for TNBC is only 77 percent, according to breastcancer.org.
A recent study published in the New England Journal of Medicine offered encouraging news, however. For the first time, immunotherapy has shown an increase in survival rates for those with TNBC. Immunotherapy stimulates the body’s immune system to recognize and combat cancer cells.
The study included 900 women from 41 countries who were divided into two groups ─ those who received chemotherapy and an immunotherapy drug, and those who received chemotherapy and a placebo. All participants had metastatic cancer, meaning that it had spread beyond the confines of the breast.
A preliminary interim analysis showed encouraging results. Those who received the immunotherapy drug had at least a 10 month longer survival rate than those taking the placebo.
The study is significant for two reasons. While immunotherapy is often used for lung cancer and lymphoma, for example, breast cancer has traditionally been regarded as unresponsive to the immune system, according to the Cancer Research Institute. This study may turn the tide for this type of treatment.
The most significant finding, however, is a possible new-found hope for those with TNBC.
