- Breast cancer is a type of cancer that starts in the breast. Cancer starts when cells begin to grow out of control.
- Breast cancer cells usually form a tumor that can often be seen on an x-ray or felt as a lump, and almost entirely in women, but men can get breast cancer, too.
- Despite dramatic advances in the cancer research setting, breast cancer remains a major health problem and currently represents a top biomedical research priority. Worldwide, breast cancer is the most common cancer affecting women, and its incidence and mortality rates are expected to increase significantly over the next 5–10 years
Anatomy of the breast:
Where does breast cancer start?
Breast cancer can start from different parts of the breast.
- Most breast cancers begin in the ducts that carry milk to the nipple (ductal cancers)
- Some start in the glands that make breast milk (lobular cancers)
- There are also other types of breast cancer that are less common like phyllodes tumor and angiosarcoma
- A small number of cancers start in other tissues in the breast. These cancers are called sarcomas and lymphomas and are not really thought of as breast cancers.
Types of breast cancer:
Breast cancer is not one disease. There are different types and subtypes of disease that are referred to as breast cancer. This is why the treatment you receive for your breast cancer may be quite different to the other treatments women may have.
Types of breast cancer
Non-invasive breast cancers:
- Ductal carcinoma in situ
- Lobular carcinoma in situ
Invasive breast cancers:
- Invasive ductal carcinoma
- Invasive lobular carcinoma
- Paget’s disease of the nipple
- Inflammatory breast cancer
- Phyllodes tumors of the breast
- Locally advanced breast cancer
- Metastatic breast cancer
Subtypes of breast cancer
The subtypes of breast cancer are based on the gene cancer expresses.
The three main subtypes are:
- Hormone receptor-positive it
- HER2 positive it
- Triple-negative it
Non-invasive breast cancers:
Non-invasive breast cancers are cancers that are contained within the milk ducts or lobules in the breast. They have not grown into or invaded the normal breast tissue. Non-invasive cancers are called carcinoma in situ and are sometimes referred to as pre-cancers.
- Ductal carcinoma in situ
Ductal carcinoma in situ (DCIS) is the most common type of non-invasive it. It starts in the milk ducts of the breast and is non-invasive because it hasn’t spread into any surrounding breast tissue. DCIS isn’t life-threatening, but having DCIS can increase the risk of developing an invasive it later in life
- Lobular carcinoma in situ
Lobular carcinoma in situ (LCIS) is non-invasive breast cancer that grows in the lobules (the milk-producing glands at the end of breast ducts). It is non-invasive as it has not spread into any surrounding breast tissue. LCIS isn’t life-threatening, but having LCIS can increase the risk of developing invasive breast cancer later on in life.
Invasive breast cancers:
Invasive breast cancers have spread outside the ducts or lobules of the breast into surrounding breast tissue. ‘Early breast cancer is the term that refers to cancer that is contained within the breast and may have spread to surrounding lymph nodes in the breast or armpit (axilla) but not anywhere else in the body.
- Invasive ductal carcinoma
Invasive ductal carcinoma (IDC) is the most common type of it. About 80% of all breast cancers are invasive ductal carcinomas. Invasive ductal carcinoma means that cancer began in the milk ducts of the breast has broken through the lining of the milk duct and spread into the surrounding breast tissue. Over time invasive ductal breast cancer can spread to the lymph nodes and potentially to other parts of the body.
- Invasive lobular carcinoma
Invasive lobular carcinoma (ILC) is the second most common type of it after invasive ductal carcinoma. Invasive lobular carcinoma means that cancer that began in the milk-producing lobules of the breast has broken through the lining of the lobule and spread into the surrounding breast tissue. Over time invasive lobular can spread to the lymph nodes and potentially to other parts of the body.
- Phyllodes tumors of the breast
Phyllodes tumors of the breast are rare. Although most phyllodes tumors are benign (not cancerous) some are malignant (cancerous). Phyllodes tumors tend to grow quickly, but they rarely spread outside the breast. Phyllodes tumors develop in the breast’s connective tissue or stroma (the tissue that holds everything together inside the breast) i.e. outside the ducts and lobules of the breast.
Subtypes of breast cancer
The three main subtypes of it are:
- Hormone receptor-positive breast cancer
About two-thirds of breast cancers are hormone receptor-positive, which means that they need female hormones (estrogen and/or progesterone) to grow and reproduce. Most people with hormone-positive breast cancer will be recommended hormone-blocking therapy such as tamoxifen, anastrozole, or letrozole. These are oral medications that are taken daily for at least five years following the completion of other breast cancer treatments (surgery, chemotherapy, and/or radiotherapy).
- HER2-positive breast cancer
HER2-positive breast cancer cells have too much of the protein called human epidermal growth factor receptor 2 on the surface of the cancer cells. These excess HER2 receptors promote the growth of cancer cells. HER2-positive breast cancer may be either hormone receptor-positive or negative.
HER2-positive breast cancers are treated with the drug Herceptin (trastuzumab), which specifically targets HER2-positive breast cancer and has been proven to be a very effective treatment. Most people with HER2-positive early will be treated with 12 months of Herceptin, along with other treatments (surgery, chemotherapy, and/or radiotherapy). They may also be offered 12 months of Nerlynx (neratinib), an oral medication used to treat HER2-positive. If breast cancer is also hormone receptor-positive, hormone-blocking therapy may be recommended.
- Triple-negative breast cancer
Triple-negative breast cancer does not have any of the three receptors commonly found in cells (estrogen, progesterone, and HER2). Around 15 percent of breast cancers are triple negative and chemotherapy is generally recommended for these cancers
Breast Cancer Signs and Symptoms
The most common symptom of it is a new lump or mass. A painless, hard mass that has irregular edges is more likely to be cancer, but breast cancers can be tender, soft, or round. They can even be painful. For this reason, it’s important to have any new breast mass, lump, or breast change checked by an experienced healthcare professional.
Other possible symptoms of it include:
- Swelling of all or part of a breast (even if no lump is felt)
- Skin dimpling (sometimes looking like an orange peel)
- Breast or nipple pain
- Nipple retraction (turning inward)
- Nipple or breast skin that is red, dry, flaking or thickened
- Nipple discharge (other than breast milk)
- Swollen lymph nodes (Sometimes breast cancer can spread to lymph nodes under the arm or around the collar bone and cause a lump or swelling there, even before the original tumor in the breast is large enough to be felt.
Diagnosing breast cancer
How to do a breast self-exam: The five steps:
Step 1: Begin by looking at your breasts in the mirror with your shoulders straight and your arms on your hips.
Here’s what you should look for:
- Breasts that are their usual size, shape, and color
- Breasts that are evenly shaped without visible distortion or swelling
If you see any of the following changes, bring them to your doctor’s attention:
- Dimpling, puckering, or bulging of the skin
- A nipple that has changed position or an inverted nipple (pushed inward instead of sticking out)
Redness, soreness, rash, or swelling
Step 2: Now, raise your arms and look for the same changes.
Step 3: While you’re in the mirror, look for any signs of fluid
coming out of one or both nipples (this could be a watery, milky,
or yellow fluid or blood).
Step 4: Next, feel your breasts while lying down, using your right hand to feel your left breast and then your left hand to feel your right breast. Use a firm, smooth touch with the first few finger pads of your hand, keeping the fingers flat and together. Use a circular motion, about the size of a quarter.
Cover the entire breast from top to bottom, side to side — from your collarbone to the top of your abdomen, and from your armpit to your cleavage.
Follow a pattern to be sure that you cover the whole breast. You can begin at the nipple, moving in larger and larger circles until you reach the outer edge of the breast. You can also move your fingers up and down vertically, in rows, as if you were mowing a lawn. This up-and-down approach seems to work best for most women. Be sure to feel all the tissue from the front to the back of your breasts: for the skin and tissue just beneath, use light pressure; use medium pressure for tissue in the middle of your breasts; use firm pressure for the deep tissue in the back. When you’ve reached the deep tissue, you should be able to feel down to your ribcage.
Step 5: Finally, feel your breasts while you are standing or sitting. Many women find that the easiest way to feel their breasts is when their skin is wet and slippery, so they like to do this step in the shower. Cover your entire breast, using the same hand movements described in step 4.
- Mammogram. A mammogram is an X-ray of the breast. Mammograms are commonly used to screen for breast cancer. If an abnormality is detected on a screening mammogram, your doctor may recommend a diagnostic mammogram to further evaluate that abnormality.
- Breast ultrasound. Ultrasound uses sound waves to produce images of structures deep within the body. Ultrasound may be used to determine whether a new breast lump is a solid mass or a fluid-filled cyst.
- Removing a sample of breast cells for testing (biopsy). A biopsy is the only definitive way to make a diagnosis of it. During a biopsy, your doctor uses a specialized needle device guided by X-ray or another imaging test to extract a core of tissue from the suspicious area. Often, a small metal marker is left at the site within your breast so the area can be easily identified on future imaging tests.
Biopsy samples are sent to a laboratory for analysis where experts determine whether the cells are cancerous. A biopsy sample is also analyzed to determine the type of cells involved in it, the aggressiveness (grade) of cancer, and whether the cancer cells have hormone receptors or other receptors that may influence your treatment options.
- Breast magnetic resonance imaging (MRI). An MRI machine uses a magnet and radio waves to create pictures of the interior of your breast. Before a breast MRI, you receive an injection of dye. Unlike other types of imaging tests, an MRI doesn’t use radiation to create the images
Treatment strategies:
These include:
- Surgery. For most people, the first step is to take out the tumor. An operation called lumpectomy removes only the part of your breast that has cancer. It’s sometimes called breast-conserving surgery. In a mastectomy, doctors remove the whole breast. There are different types of mastectomies and lumpectomies.
- Radiation therapy. This treatment uses high-energy waves to kill cancer cells. Most women under age 70 who have a lumpectomy get radiation, too. Doctors also might recommend this method if the disease has spread. It helps destroy any cancer cells that the surgeon couldn’t remove. Radiation can come from a machine outside your body, or you might have tiny seeds that give off radiation placed inside your breast where the tumor was.
- Chemotherapy uses drugs to kill cancer cells. You take the medicines as pills or through an IV. Most people get it after surgery to kill any cancer cells left behind. Doctors also prescribe it before surgery to make tumors smaller. Chemo works well against cancer, but it also can harm healthy cells.
- Hormone therapy uses drugs to prevent hormones, especially estrogen, from fueling the growth of breast cancer cells. Medicines include tamoxifen for women before and after menopause and aromatase inhibitors including anastrozole exemestane and letrozole for postmenopausal women. Some types of this therapy work by stopping the ovaries from making hormones, either through surgery or medication. Fulvestrant is an injection that keeps estrogen from attaching to cancer cells.
- Targeted therapy such as lapatinib , pertuzumab, and trastuzumab trigger your body’s immune system to help destroy cancer cells. These medicines target it cells that have high levels of a protein called HER2. T-DM1, or ado-trastuzumab emtansine is a medicine that combines Herceptin and the chemotherapy medicine emtansine to target HER2-positive cancer cells. Abemaciclib , palbociclib , and ribociclib are often used with an aromatase inhibitor or fulvestrant (Faslodex), in women with certain types of advanced cancer. Abemaciclib can be used alone in women who have already been treated with hormone therapy and chemotherapy. Alpelisib is a PI3K inhibitor that treats it in men and women who have a certain gene change resulting from treatment with hormonal therapy. Neratinib also works against HER2-positive it by blocking the cancer cells from getting growth signals. A new class of drugs called PARP (poly ADP ribose polymerase) inhibitors targets an enzyme that feeds cancer cells. PARP inhibitors include olaparib and talazoparib .
- Immunotherapy uses your own immune system to target cancer. The drugs atezolizumab and sacituzumab govitecan-hziy have been approved to treat triple-negative it that has spread.
References:
- Anastasiadi Z, Lianos GD, Ignatiadou E, Harissis HV, Mitsis M. it in young women: an overview. Updat Surg. 2017 Sep;69(3):313–7.
- https://www.cancer.org/cancer/breast-cancer/about/types-of-breast-cancer.html
- https://www.bcna.org.au/breast-health-awareness/breast-cancer-screening/
- https://www.breastcancer.org/symptoms/testing/types/self_exam
- https://www.mayoclinic.org/