Breast cancer affects one in every eight American woman. If detected and treated early, it is highly curable.
- What is breast cancer?
- Hormone receptors and HER2/neu
- Next steps
What is breast cancer?
Breast cancer develops when cells in the breast divide and grow without their normal controls. Cancer cells also don’t organize normally. Instead they grow into a tumor, which may invade nearby tissue and spread to other organs.
- In the United States, breast cancer is the second most common cancer in women (after skin cancer). About 319,000 people are newly diagnosed with breast cancer each year.
- Over a woman’s lifetime, there’s a one in eight chance she will get breast cancer. For men, the lifetime risk is much lower — about one in 1,000.
- The content in this section is mainly aimed at women, who make up 99 percent of all breast cancer patients. Most of the information applies to men as well.
Types of breast cancer
Breast cancers fall into these two main types:
- In situ breast cancer
- Invasive breast cancer
In situ breast cancer
In situ breast cancer is only in the milk ducts and lobules (milk-producing glands). This type is also called noninvasive breast cancer.
Ductal carcinoma in situ (DCIS) is the most common noninvasive breast cancer. It is early-stage cancer confined to the milk ducts. Usually it causes no physical signs or symptoms and is detected by a screening mammogram.
Many women with DCIS can be cured by removing the tissue that contains the tumor. Left untreated, DCIS can become invasive cancer.
Invasive breast cancer
Invasive breast cancer can start in the ducts or lobules but then spreads into surrounding breast tissue. It may eventually become metastatic, meaning it spreads to other organs, like the bones or lungs. Invasive breast cancer is also called infiltrating breast cancer.
These are the most common types of invasive breast cancer.
- Invasive ductal carcinoma: This type begins in a duct in the breast and breaks through into the surrounding fatty tissue of the breast. From there, it can spread to other parts of the body through the bloodstream or lymph. About 80 percent of invasive breast cancers are invasive ductal carcinomas, also called infiltrating ductal carcinomas.
- Invasive lobular carcinoma: This type starts in the lobules and can spread to other parts of the body. It is also called infiltrating lobular carcinoma. This is the second most common type of invasive breast cancer.
- Inflammatory breast cancer: Only about 1 to 3 percent of women with breast cancer have the inflammatory type. This rare cancer may begin in either the ducts or the lobules. It is aggressive and progresses rapidly. In its early stages, it can be mistaken for infection because the symptoms are similar. Most infections will respond to antibiotics, but inflammatory breast cancer will not.
Other rare types of breast cancer include Paget’s disease of the nipple and phyllodes tumors.
Symptoms of breast cancer
Early detection is key to treating and curing breast cancer. Women with smaller, early-stage cancer have more treatment options and a better chance for a cure.
If you’re concerned about a breast lump or other symptom that may result from breast cancer, ease your mind and have it evaluated at the Breast Health Clinic at SCCA or UW Medical Center–Roosevelt in the University District.
Common warning signs
Many women regularly examine their breasts to look for common warning signs. These include:
- A painless lump in the breast
- Abnormal thickening of the breast tissue
- A change in the density of the breast
Less often, breast cancer can show up as:
- A lump under the arm
- Red or scaly skin on the breast
- A change in the nipple (such as discharge or inversion)
- Dimpling of the skin
Inflammatory breast cancer symptoms
Inflammatory breast cancer may make your breast red, swollen and warm to the touch, similar to the symptoms of an infection. The surface of your breast may look pitted, like the skin of an orange, because the cancer cells block lymph vessels in your skin. Typically there is no single lump in the breast.
Diagnosing breast cancer
If you notice any change in the feel, appearance or texture of either of your breasts, schedule a clinical breast examination with your health care provider. Most breast lumps are not cancerous, but it’s important to have an exam — and possibly tests — to be sure.
A diagnostic mammogram is used to evaluate a woman with a breast problem or symptom or an abnormal finding on a screening mammogram. It usually includes additional views of one or both breasts.
SCCA was the first in the region to offer digital mammography for more accurate diagnosis. Many studies show that doctors who specialize in mammography, like they do at SCCA, are more accurate at interpreting the images when compared to doctors with less experience.
If your mammogram turns up anything suspicious, you may be asked to have an additional mammogram or an ultrasound. Breast ultrasound is used to evaluate lumps that are hard to see on a mammogram. Because of the ways different substances interact with sound waves, ultrasound can often reveal whether a lump is a solid mass or a fluid-filled, non-cancerous cyst.
Magnetic resonance imaging (MRI)
Breast MRI is an important test for some women. It can help detect breast cancers that are harder to see on a mammogram. SCCA radiologists are experts at obtaining high-quality breast MRI images and identifying which women will benefit the most from MRIs. We also conduct breast MRI research and clinical trials that examine how to best use this technology.
In a biopsy, a doctor removes a sample of cells from a suspicious area. Then a pathologist examines the sample under a microscope.
A biopsy is the only way to tell if cancer is really present. A biopsy can also reveal details about the cancer that influence treatment decisions.
You may have one of these types of biopsy:
- Fine-needle biopsy — using a needle to extract fluid or cells from a lump that can be felt or seen with ultrasound or on a mammogram.
- Core biopsy — nearly the same as a fine-needle biopsy but with a larger needle to remove a small cylinder of breast tissue.
- Stereotactic needle biopsy — done when the lump is so small that the doctor cannot insert the biopsy needle accurately. You lie face down on a special table with an opening that lets your breast hang down. A mammogram shows the location of the lump and a computer guides the needle.
- Surgical biopsy — surgery to remove all or part of a breast lump.
During surgery for breast cancer, you may also have one or more lymph nodes removed and biopsied to check whether cancer cells have spread into your lymph system.
Grades of breast cancer
The grade of an invasive breast cancer refers to how closely the cancer cells resemble normal breast cells under a microscope. Determining the grade is part of your biopsy.
- A lower number usually means a slower-growing cancer that is less likely to spread.
- A higher number usually means a faster-growing cancer that is more likely to spread.
There are three grades.
- Grade 1 (well differentiated): The cells in these cancers are relatively less abnormal looking. They do not appear to be growing rapidly.
- Grade 2 (moderately differentiated): The cancer cells are somewhat more abnormal.
- Grade 3 (poorly differentiated): These cancer cells look the most abnormal. They tend to grow and spread more aggressively.
Hormone-receptor and HER2/neu status
Your care team will try to determine other traits of your breast cancer when they check the sample of tissue removed during your biopsy or a sample taken when your entire tumor is removed surgically. Specifically, they will be looking for your hormone-receptor status and HER2/neu status.
Hormone-receptor positive breast cancer
Most women with breast cancer have hormone-receptor positive (HR+) disease. This means their cancer cells have one or both of these:
- Receptors where estrogen can attach (estrogen-receptor positive, or ER+, disease)
- Receptors where progesterone can attach (progesterone-receptor positive, or PR+, disease)
Most women have both types of receptors. If your cancer is HR+, this helps doctors predict that your cancer will respond to hormonal therapy.
HER2-positive breast cancer
Some women with breast cancer have HER2-positive disease. This means their cancer cells make too much of a protein called HER2/neu, which indicates that the cancer may be more aggressive.
If your cancer is HER2 positive, this helps doctors predict that your cancer will respond to certain targeted biological therapies.
Triple-negative breast cancer
This term refers to breast cancers that are:
- Not estrogen-receptor positive
- Not progesterone-receptor positive
- Not HER2 positive
Stages of breast cancer
Doctors use your cancer’s stage to help plan the best treatment for you. Stage refers to the extent of your cancer, such as the size of the tumor and if it has spread.
There are two main systems for determining the stage of breast cancer:
- TNM staging
- Overall stage grouping
TNM stands for tumor, nodes and metastasis. Your TNM stage will consist of:
- The letter T followed by a number from 0 to 4. A higher T number means the tumor is larger, has spread more widely into nearby tissues or both.
- The letter N followed by a number from 0 to 3. A higher N number means greater spread of cancer cells to lymph nodes near the breast, such as in the armpit (axilla) or under the collarbone (clavicle).
- The letter M followed by a 0 or 1. M0 means a physical exam and imaging studies, such as X-rays, have not found cancer in lymph nodes away from the breast or in distant organs; M1 means distant spread was found.
Overall stage grouping
Once your doctor determines your TNM, they will assign a stage using overall stage grouping, also known as Roman-numeral staging.
- Stage 0: Noninvasive cancers (ductal carcinoma in situ, or DCIS, and lobular carcinoma in situ, or LCIS) are considered stage O.
- Stage I: The tumor is smaller than 1 inch, and the cancer has not spread to the lymph nodes under your arm or to other sites beyond your breast.
- Stage II: The tumor is 1 to 2 inches in size, or the cancer has spread to the lymph nodes under your arm. Stage I or II cancers may be called early-stage cancers.
- Stage III: This is a more advanced cancer, but it is still confined to your breast, surrounding tissues and lymph nodes. Stage III cancers may be considered early-stage or advanced cancers.
- Stage IV: Cancer has spread or metastasized to distant sites, such as your lungs, liver, bones and brain, or to lymph nodes beyond your underarm area.