The landscape of breast cancer treatment has been rapidly changing. Advances in diagnosis and treatment provide very effective options for breast cancer and dramatically improve survival rates when breast cancer is diagnosed and treated early. One of the biggest changes are treatments that can target specific receptors or proteins on breast cancer cells to further help patients in their fight against breast cancer.
Breast cancer tumors are tested for molecular and genetic changes as well as the presence of hormone receptors and HER2 receptors. The findings of a breast biopsy reveal if specific receptors are present in the cancer cells. There can be receptors present for:
- Estrogen
- Progesterone
- HER2 protein
Identifying which receptors are present makes it possible for the oncologist to develop the best treatment plan available today to destroy the cancer cells while protecting your healthy cells from as much damage as possible.
Some of these treatments are in a category called hormone therapy, while other drugs are considered targeted therapies. Not every type of breast cancer can be treated with hormone therapy and/or targeted therapy, depending on the molecular findings. Let’s take a look at what hormone and targeted therapies do, who can use them, and the types of side effects breast cancer patients might expect from each type of treatment.
What is Hormone Therapy for Breast Cancer?
When cancer develops in the breast, its growth can be stimulated by hormones that naturally occur in the body. Called hormone-sensitive cancers, they contain hormone-receptor proteins with estrogen or progesterone receptors. If they lack estrogen or progesterone receptors, they’re hormone-receptor negative and would not be treated with hormone therapies.
About 70-80% of breast cancers have hormone receptors. These receptors become active and start producing additional cancer cells when hormones bind to them. Hormone therapy drugs block those hormones from attaching to the receptors to help stop new cancer cell creation.
When Are Hormone Therapy Given?
Hormone therapy medications control hormones by blocking the body’s hormone production or altering the way hormones work in the body. Organs that secrete hormones (ovaries) may be removed by surgery, radiation, or the drug goserelin to fight cancer.
Before Surgery: This is called neoadjuvant treatment. The goal is to reduce the tumor’s size, so there is less to remove during surgery. Not everyone has treatments before surgery. Your oncologist will let you know if this is right for you.
Adjuvant therapy for early-stage breast cancer uses hormone therapy after surgery to stop cancer from coming back. It blocks the effects of estrogen or progesterone on cancer cells but does not stop the hormone from being produced.
After cancer has gone into remission, women with estrogen-positive breast cancer can use a hormone therapy regimen for about five years to help keep it from returning. Some women may benefit from treatment periods that last longer than five years.
What Are the Side Effects of Hormone Therapy?
Side effects depend on the specific drug or type of treatment. Some of the more common side effects of hormone therapy are:
- Blood clots in the lungs and legs
- Stroke
- Weakness, fatigue
- Nausea, vomiting, constipation, or diarrhea
- Depression, mood swings
- Bone loss
- Skin rash
- Joint or muscle pain
- Loss of appetite, weight loss
- Loss of libido
- Aromatase inhibitors are linked to heart attack, heart pain, heart failure, and high cholesterol levels
What is Targeted Therapy for Breast Cancer?
Targeted therapy focuses only on killing cancer cells and minimizing damage to normal, healthy cells. It can provide a better outcome with fewer side effects for certain types of breast cancer.
HER2+ breast cancer is a primary diagnosis that calls for the use of targeted therapy for breast cancer. HER2 is an acronym for Human Epidermal Growth Factor Receptor 2. This type of cancer diagnosis means that the cancerous cells are producing too much of the protein. An overabundance of HER2 protein creates more rapid and aggressive cancer growth. However, targeted therapies specific to HER2 tend to be very effective at stopping cancer from continuing to grow and replicate.
Types of Targeted Therapy Most Often Used for Breast Cancer Treatment
There are several different types of targeted therapy that are used for patients depending on their specific needs. The different types of targeted therapy include:
Monoclonal antibodies
Artificial antibodies are grown in a lab and modified to attack specific cancer cells. Used with chemotherapy and radiation, they can better target cancer cells. The CDK4/6 antibody inhibits advanced cancer cells’ ability to divide and multiply and slows metastasis, so other treatments have time to work. This approach is used for patients that are HER2+ and is currently the most frequently used targeted therapy.
Antibody-Drug Conjugates (ADC)
This treatment approach utilizes a monoclonal antibody along with chemotherapy. This approach can help the targeted therapy not only bind to the receptor on the cancer cell but also deliver chemotherapy to the cancer cells.
Kinase Inhibitors
Kinase proteins (which are also HER2 proteins) signal cells to grow. Kinase inhibitors block the receptors where kinase normally binds to the cancer cell and helps to block the message from being delivered, helping to stop or slow the growth of cancer.
What Are the Side Effects of Targeted Therapies?
Targeted therapies have far fewer side effects than chemotherapy or radiation. While many of the side effects are similar, there are some key differences. One of the most pertinent is that you don’t experience hair loss. Additionally, chemotherapy frequently damages the surrounding healthy cells in addition to cancerous cells, while targeted therapy tends to damage only cancerous cells. Some of the most common side effects of targeted therapy may include:
- Diarrhea or nausea
- Liver problems, hepatitis
- Skin rashes, dry skin, changes to nails, and loss of skin pigment
- Mouth sores
- Increased risk of infections
- Problems with wound healing and blood clotting
- Shortness of breath or cough
- High blood pressure
- Low blood cell counts, anemia
- Fatigue and weakness
- Loss of appetite, weight loss
- Muscle or joint pain
The Latest in Breast Cancer Treatments Are Available in Portland and Vancouver
Understanding the molecular makeup of each patient’s breast cancer allows the oncologist to select the most appropriate and proven treatments available today. At Compass Oncology, our comprehensive treatment team includes breast cancer specialists, breast surgeons, specialists in genetics, pathologists, and diagnostic imaging.
Compass Oncology’s care team focuses on helping each patient through their individual cancer journey with treatments and support throughout. If you or a loved one in the Portland, Oregon, or Vancouver, Washington area have been diagnosed with breast cancer, schedule a consultation today to learn if targeted or hormone therapies can help you.
