WHAT TYPES OF BREAST CANCER ARE THERE?
Breast cancer comes in different types, degrees of aggressiveness (grades), and extent of disease (stages). To best explain the different types of cancer, we need to first discuss the normal anatomy of the breast. The breast tissue consists of glands whose purpose is to produce the milk, ducts that deliver the milk, fat, stroma, or supporting elements of the breast, lymphatics, nerves, vessels.
The largest area of the breast tissue is occupied by glands and ducts. Approximately 85% of breast cancers are “ductal” while 15% are lobular. The junction or transition of different elements is considered a weak spot for cellular abnormality to take place. Most breast cancers start at the junction of the terminal ductal lobular unit, called TDLU for short. From there, the cancer cells continue to be mostly ductal or lobular. Some cell types are mixed and we refer to these as “mixed ductal and lobular” or ductal with lobular features and so on.
The degree of what we call “cancer cells” which are still contained within the duct or lobule as its earliest stage is considered Stage 0 Breast Cancer. You may have heard the term Ductal Carcinoma In Situ (DCIS) or Lobular Carcinoma in Situ (LCIS). The In Situ term refers to cells that are still in position or contained within the duct or lobule and have not broken past the basement membrane. Mammography is the best imaging exam to detect microcalcifications which can be the earliest sign of Stage 0 Breast Cancer.
Some cancers are still very local (stage 0 or stage 1) within the breast, meaning they have not spread, but are no longer contained within the duct or lobule. We refer to these cancers as “invasive” breast cancers. This name is a little bit of a misnomer for patients hearing this because they might falsely assume that cancer has spread. This term used to be called “infiltrating” breast cancer which I prefer as a physician specializing in breast cancer discussing these results with patients on a daily basis. Ultrasound of the breast is typically used to evaluate masses that may present on a screening mammogram or evaluated more closely by a diagnostic mammogram. The breast ultrasound is used to see through the dense breast tissue to more fully characterize a mass. A suspicious appearing mass within the breast can be biopsied by ultrasound-guided breast biopsy to determine if the mass is cancerous.
Let’s talk about the difference between Grade and Stage of Breast Cancer. Grade refers to how aggressive the breast cancer cell type is based on measuring certain qualities such as division (mitotic rate), nuclear appearance, and the degree of gland formation. There are three grades of Breast Cancer: grade 1, 2, and 3. Grade 1 is the least aggressive and grade 3 is the most aggressive.
There are also other determinants of how a breast cancer cell or type may react and this is important to treatment options. If the cancer cell still has a reasonable detection (avidity or positivity) for estrogen or progesterone, we call this Estrogen positive (ER-positive) or Progesterone Positive (PR-positive) breast cancer. This is usually a good thing because it means that the cell is not so altered that it still bears a resemblance to how a normal cell would act. It also means that we can use certain medicines such as anti-estrogen medicines like Tamoxifen or Aromatase inhibitors to block the body’s estrogen influence on the cells, in essence like stopping the fertilizer. Some cells express a particular protein on their surface Her2 Neu. We find if the tumor has this characteristic, then it will respond well to particular chemotherapy invented just for this type of expression called Herceptin which is a kind of chemotherapy. If a breast cancer cell is very abnormal and expresses none of these receptors or markers we call it “Triple Negative” meaning that it does not express ER or PR or Her2. These more aggressive cells typically require special chemotherapy to obliterate the cancer cells. Some types of breast cancer are very localized to like a particular area of the breast, like Paget’s disease which is DCIS of the nipple. Other types of cancer cells are diffuse within the skin of the breast like inflammatory breast cancer.
Then what does Staging of Breast Cancer mean? Staging describes the extent to which a cancer cell is still localized within the duct/lobule (Stage 0) or within the breast (Stage 1) or nearby involvement of lymph nodes (Stage 2 or 3) or has spread to more distant organs (Stage 4) such as lung or bone. Most cancers present as Stage 0 or Stage 1. When breast cancers have spread to the nearby nodes, such as axillary lymph nodes, I tell patients that is not necessarily a bad thing. “Thank goodness that the lymph nodes are there to catch the cancer cells from going beyond that point”. One may have only a few micrometastases within the regional lymph nodes or there may be an abundance of cells that the lymph nodes cannot contain which then spills over to other organs such as the bone. MRI can be performed on any part of the body including the breast to further evaluate for extent of breast cancer spread or can be used to evaluate more distant metastasis such as the brain. There have been incredible advancements in the treatment of stage 2-4 breast cancer over the past five years. This means that women with more advanced disease can typically live a long healthy life after initial treatment, with careful close observations from their care team which consists of specialists in all areas from radiologist, pathologist, surgeon, medical and radiation oncologist, a support team of nurses, psychological, other specialties as needed.
The Women’s Imaging Center uses the highest-rated breast imaging and comprehensive mammography and medical diagnostic imaging exams for women including 3D mammograms, screening mammograms, and diagnostic mammograms, breast ultrasound, and body ultrasound, MRI of breast, and body, breast biopsy, genetic counseling, and testing. We offer breast MRI and other Medical Diagnostic Imaging MRI services at our Denver/Cherry Creek location. The Women’s Imaging Center also provides most other Women’s Imaging and Mammography Services at our other Denver metro area locations including Women’s Imaging- West/Lakewood, Women’s Imaging-South/Highlands Ranch, and Women’s Imaging-North/Westminster locations, and soon to open Centennial location.