GoodRx Guide
Breast Cancer: Your GoodRx Guide
Comprehensive information for you or a loved one — including treatment options and discounts on popular medications.
Definition
Breast cancer is the second most common cancer among women, and 1 in 8 women will be diagnosed at some point in their life.
Breast cancer starts when healthy cells have a change in their DNA that allows them to multiply uncontrollably. As these cells grow in number, they form a tumor. The cancerous tumor then has the potential to invade surrounding tissues. It can even travel to distant parts of the body and create new tumors (referred to as metastases or “mets”).
There are different kinds of breast cancer. The type of breast cancer is determined by where in the breast the cancer first starts. Most commonly, breast cancer starts in the breast tissue responsible for milk production.
A ductal carcinoma, a tumor that starts in the milk ducts, is the most common type of breast cancer.
Causes
It’s not always clear why some people develop breast cancers and others don't. But researchers have identified some factors that increase a person’s odds of developing breast cancer.
Some of these risk factors are unavoidable:
Age. Most cases are diagnosed after the age of 50.
Genetics. There are certain inherited genetic mutations (like BRCA1, BRCA2, and PALB2) that increase the likelihood of breast cancer.
Increased estrogen exposure. This includes people who were born as female, started menstruating early or went through menopause later in life, or people who were never pregnant.
Other risks are related to factors that can change based on life circumstances. Things that may increase risk are:
Increased percentage of body fat
Physical inactivity
Alcohol consumption (more than 1 to 2 drinks per day)
Hormone treatments — medications that contain estrogen, like birth control pills or hormone replacement therapy
Similar to many other conditions, it’s likely a combination of genes and environmental exposures that causes breast cancer.
Symptoms
Breast cancer often doesn’t produce any symptoms, particularly in the earlier stages. This is why routine screening with mammography is so important.
Sometimes, especially with breast self-exams, people can see or feel abnormal lumps in the breast. Certain types of breast cancer can also lead to changes in the skin, such as areas of redness or a change in the appearance of the nipple.
If a breast cancer starts to spread, it typically first travels to nearby lymph nodes. So some people may notice swollen lymph nodes in their armpit or around their collar bone. Breast cancer symptoms vary more if it metastasizes to more distant parts of the body. The most common areas of metastasis are the lungs, liver, brain, and bones. Metastatic tumors in these areas can lead to:
Shortness of breath or chest pain (lungs)
Pain in the abdomen, yellowing of the skin, nausea and vomiting (liver)
Headaches, seizures, or stroke-like symptoms (brain)
Bone pain and abnormal fractures of the bone (bone)
Diagnosis
A breast cancer diagnosis can begin in several different ways. Someone may feel a lump on a breast self-exam or notice changes to the skin or nipple. And then they’ll have a mammogram or ultrasound for further evaluation. In other cases, diagnosis starts with a mammogram that’s part of routine screening. This may detect an abnormal group of cells.
If a mammogram picks up on an area that may be developing cancer, often the next step in the diagnostic process is to get a biopsy. This procedure uses a small needle to get a sample of the suspicious cells. Then that sample is analyzed under a microscope to determine if the cells are cancerous.
If cancer is confirmed, the next step is to stage the cancer. Staging takes into account multiple factors, including how big the tumor is, how far the cancer has spread, how quickly the tumor is growing, and whether there are certain receptors on the cancer cells. Staging helps qualify how advanced a cancer is. It also provides useful guidance for treatment options.
Treatments
There are many different types of treatment for breast cancer. It can be helpful to break them up into two categories.
1) Localized treatments specifically target the cancer cells in an identifiable tumor. This includes:
Surgery: removes the tumor
Radiation: directs high energy beams at the cancer cells to destroy them
2) Systemic (“whole body”) treatments are medications that are delivered to the whole body. These treatments kill the cells in a known tumor. These also destroy other cancer cells that may be circulating in the body, along with any metastatic tumors. Systemic treatments include:
Chemotherapy: kills rapidly dividing cells (like cancer)
Hormone therapy: prevents cancer growth by blocking estrogen-sensitive receptors
Targeted therapy: blocks other types of receptors that help the cancer grow
Immunotherapy: helps the immune system identify and kill cancer cells
Choosing the best options depends on the type of breast cancer you may have. Personal preferences and treatment goals also play an important role.
Living with breast cancer
If you or a loved one has been diagnosed with breast cancer, it’s natural to focus on scheduling oncology appointments, getting all the testing done, or starting a treatment plan as soon as possible.
Allow yourself the time and space to process your diagnosis. It’s important to think about your goals and priorities in your care. This will help you build a treatment plan and support system that’s most effective and meaningful to you. Everyone’s breast cancer journey is different. And it can be helpful to remember that you’re in the driver’s seat when it comes to mapping out that journey.
Prevention
When you think about ways to prevent breast cancer, it helps to know whether you’re at higher risk for the disease. But even with no risk factors, it’s still possible to develop breast cancer. So early detection with regular mammograms is the best way to prevent breast cancer.
Some risk factors are out of our control — like being assigned female at birth, inherited genes, age, and menstrual history. But here’s the good news: There are also risk factors in our control. Some things you can do to help prevent breast cancer include:
Limit alcohol to less than 1 to 2 drinks per day
Consider quitting or cutting back on smoking
Limit medications that increase your exposure to estrogen, such as birth control pills or hormone replacement therapy
Common concerns
Some breast cancer cells have receptors that bind to hormones or molecules to help the cancer cells grow. Receptors include:
Estrogen receptors (ER)
Progesterone receptors (PR)
Human epidermal growth factor receptor 2 (HER2)
Breast cancer cells are called “receptor positive” when these receptors are present. They’re called “receptor negative” when the receptors are absent. A cancer can have any combination of these receptors, or none at all (which is called “triple negative”). This is important to know because it affects how cancers respond to different treatments.
Most people don’t experience pain from their breast cancer. It’s more common to experience unpleasant side effects from the treatment. Examples include pain after surgery, pain in an area that received radiation, or body aches from chemotherapy or immunotherapy.
While less common, breast cancer itself can be painful if the tumor is large or has spread to areas where it’s causing pain. Examples include breast tumors that erode the skin, swollen lymph nodes, or metastatic tumors in the bone.
If you experience pain from your cancer or treatment, there are many options for ways to ease your symptoms.
Most people with stage 1 to 4 breast cancer will receive chemotherapy as part of their treatment plan. (Chemotherapy is rarely used in stage 0 cancer). Healthcare providers often recommend chemotherapy even when a breast tumor is surgically removed and there’s no evidence of further spread. This is because it's possible that a few of the cancer cells have broken away from the tumor and made their way into the bloodstream or lymphatic system. If it’s just a small amount of cells, diagnostic tests can’t detect them. Chemotherapy is helpful because it kills cancer cells no matter where they’re hiding
The treatment goal for stage 0, 1, 2, and 3 breast cancer is to cure the cancer. And in most cases, a cure is possible. People who have been cured of breast cancer are still at risk for recurrence or a return of the cancer. But many of them live the rest of their lives free of cancer.
Stage 4 breast cancer means that the tumor has spread (metastasized) to other parts of the body. Metastatic breast cancer is not curable. But there are still treatment options for people with stage 4 cancer that can help them live longer and happier lives.
References
American Cancer Society. (2019). Genetic counseling and testing for breast cancer risk.
Centers for Disease Control and Prevention. (2021). Breast cancer statistics.
Centers for Disease Control and Prevention. (2021). What are the risk factors for breast cancer?
Breastcancer.org. (2014). Abnormal PALB2 gene increases breast cancer risk more than previously thought.
Liang, D.H. (2020). Circulating tumor cells in breast cancer. Recent Results in Cancer Research.
McDonald, J. A., et al. (2013). Alcohol intake and breast cancer risk: Weighing the overall evidence. Current Breast Cancer Reports.
National Cancer Institute. (2021). The breast cancer risk assessment tool.
Pizot, C., et al. (2016). Physical activity, hormone replacement therapy and breast cancer risk: A meta-analysis of prospective studies. European Journal of Cancer.
