by Dr. Suleiman Massarweh
Women with breast cancer could someday benefit from new drugs being tested at the University of Kentucky's Markey Cancer Center, where researchers are looking for ways to prolong the effectiveness of existing hormone therapies.
At least two-thirds of all breast cancers are classified as hormone positive, or estrogen-receptor positive, meaning that the cancer is dependent on the hormone estrogen for growth.
About 700,000 women with estrogen-receptor positive breast cancer are diagnosed every year worldwide. Hormonal therapies (also called anti-estrogen therapy) are critical tools in controlling breast cancer progression in these cases.
Hormone therapies are easy to take, are relatively inexpensive, and are a lot less toxic than chemotherapy drugs. Most hormone therapies, such as the commonly used drug tamoxifen and the newer aromatase inhibitors, are taken as pills. These therapies have a great advantage in preserving patient quality of life – an important consideration, especially for patients with incurable metastatic breast cancer.
Unfortunately, in essentially all women with metastatic breast cancer, the disease eventually becomes resistant to hormone therapy after a period of several months on average. Then, stronger, more toxic treatments such as chemotherapy are needed. Resistance and treatment failure can be very disheartening to patients, their families, and their physicians alike. So, physician-scientists are trying to find ways to make tamoxifen and similar drugs work for longer or find ways to overcome that resistance.
Unraveling the causes of resistance and finding ways to overcome it is an important research goal in breast cancer and has been a major focus of the breast cancer research program at the Markey Cancer Center. Thanks to a tremendous amount of revealing research, we know now that alternative growth factor signals allow the cancer to escape the anti-tumor effect of hormonal therapy, and breast cancer becomes resistant through adaptation and survival despite treatment.
A number of new types of targeted drugs are now being tested in patients with hormonal resistance. We are trying to use additional targeted therapies that suppress these rogue growth signals in a smart way by adding these novel agents to hormonal agents in order to enhance their effects and prevent resistance.
Ultimately, and ideally, we would like to give patients with breast cancer a bunch of pills to take home, without their having to stay and get intravenous chemotherapy. Making treatment work for longer and with minimal toxicity is the fundamental objective.
This is the premise behind several ongoing clinical trials at the Markey Cancer Center in this area of research, something that distinguishes it from other breast cancer treatment centers in the region. This is an area of expertise that adds new treatment options for patients faced with incurable metastatic breast cancer.
Hormonal therapies are a great treatment tool for breast cancer. If only we can make them work for longer, then we can offer patients with metastatic disease more treatment options while helping to preserve their quality of life. If we can use less toxic, more targeted treatments that are simpler to deploy, then we can simplify treatment for patients with breast cancer everywhere.
Dr. Suleiman Massarweh is a professor of medicine in the University of Kentucky College of Medicine and a breast oncologist at the Markey Cancer Center.