Breast cancer Types, stage and grades
TYPE
The type of breast cancer is determined by the specific cells in the breast that are affected. Most breast cancers are carcinomas, which are tumors that start in the epithelial cells that line organs and tissues throughout the body. When carcinomas form in the breast, they are usually a more specific type called adenocarcinoma, which starts in cells in the ducts (the milk ducts) or the lobules (milk-producing glands).
In situ vs. invasive breast cancers
The type of breast cancer can also refer to whether the cancer has spread or not. In situ breast cancer (ductal carcinoma in situ or DCIS) is a cancer that starts in a milk duct and has not grown into the rest of the breast tissue. The term invasive (or infiltrating) breast cancer is used to describe any type of breast cancer that has spread (invaded) into the surrounding breast tissue.
Ductal carcinoma in situ (DCIS): Ductal carcinoma in situ (DCIS; also known as intraductal carcinoma) is a non-invasive or pre-invasive breast cancer.
Invasive breast cancer (ILC or IDC): Invasive (or infiltrating) breast cancer has spread into surrounding breast tissue. The most common types are invasive ductal carcinoma and invasive lobular carcinoma. Invasive ductal carcinoma makes up about 70-80% of all breast cancers.
Triple-negative breast cancer: Triple-negative breast cancer is an aggressive type of invasive breast cancer that accounts for about 15% of all breast cancers. It is a difficult cancer to treat.
Inflammatory breast cancer: Inflammatory breast cancer is an uncommon type of invasive breast cancer. It accounts for about 1% to 5% of all breast cancers.
Paget disease of the breast: Paget disease of the breast starts in the breast ducts and spreads to the skin of the nipple and then to the areola (the dark circle around the nipple). It is rare, accounting for only about 1-3% of all cases of breast cancer.
Phyllodes tumor: Phyllodes tumors are rare breast tumors. They develop in the connective tissue (stroma) of the breast, in contrast to carcinomas, which develop in the ducts or lobules. Most are benign, but there are others that are malignant (cancer).
Angiosarcoma: Sarcomas of the breast are rare making up less than 1% of all breast cancers. Angiosarcoma starts in cells that line blood vessels or lymph vessels. It can involve the breast tissue or the skin of the breast. Some may be related to prior radiation therapy in that area.
SUBTYPE*
Breast Cancer Hormone Receptor Status
Breast cancer cells may have one, both, or none of these receptors**.
ER-positive: Breast cancers that have estrogen receptors are called ER-positive (or ER+) cancers.
PR-positive: Breast cancers with progesterone receptors are called PR-positive (or PR+) cancers.
Hormone receptor-positive: If the cancer cell has one or both of the receptors above, the term hormone-receptive positive (also called hormone-positive or HR+) breast cancer may be used.
Hormone receptor-negative: If the cancer cell has neither the estrogen nor the progesterone receptor, it's called hormone-receptor negative (also called hormone-negative or HR-).
HER2 positive Breast Cancer status
HER2 is a growth-promoting protein on the outside of all breast cells. Breast cancer cells with higher than normal levels of HER2 are called HER2-positive. These cancers tend to grow and spread faster than other breast cancers, but are much more likely to respond to treatment with drugs that target the HER2 protein.
SUBTYPE RECAP:
Hormone Receptor - positive: the cancer cells contain receptors for the hormones stronger or progesterone. This means the cancer depends on one or both of these hormones to grow.
HER2- Positive: the cancer cells have excess HER2 protein causing the cancer to grow.
Triple Negative: the cancer cells do not have hormone receptors or excess HER2 protein. Something else is causing the cancer to grow.
*A patient could have a combination of subtypes and/or other factors contributing to cancer growth.
**Receptors are proteins in or on cells that can attach to certain substances in the blood. Normal breast cells and some breast cancer cells have receptors that attach to the hormones estrogen and progesterone, and depend on these hormones to grow. Keeping the hormones estrogen and progesterone from attaching to the receptors can help keep the cancer from growing and spreading.
STAGE
STAGE 0
Stage 0 describes non-invasive breast cancers. There is no evidence of cancer cells invading tissue.
STAGE I
Stage I describes invasive breast cancer in which the tumor measures up to 2 centimeters. No lymph nodes are involved at this stage.
STAGE II
Stage II is divided into subcategories known as IIA and IIB.
STAGE IIA
Stage IIA describes invasive breast cancer in which: No tumor can be found in the breast, but cancer cells are found in the lymph nodes. The tumor measures 2 centimeters or less and has spread to the lymph nodes. The tumor is from 2 centimeters to 5 centimeters and has not spread to the lymph nodes.STAGE IIB
Stage IIB describes invasive breast cancer in which: The tumor is from 2 centimeters to 5 centimeters and has spread to the lymph nodes. The tumor is larger than 5 centimeters but has not spread to the lymph nodes.
STAGE III
Stage III: Stage III is divided into subcategories known as IIIA, IIIB, and IIIC.
STAGE IIIA
Stage IIIA describes invasive breast cancer in which: No tumor is found in the breast. Cancer is found in lymph nodes that are clumped together or sticking to other structures, or cancer may have spread to lymph nodes near the breastbone. The tumor is 5 centimeters or smaller and has spread to lymph nodes that are clumped together or sticking to other structures. The tumor is larger than 5 centimeters and has spread to lymph nodes that are clumped together or sticking to other structures.STAGE IIIB
Stage IIIB describes invasive breast cancer in which: The tumor may be any size and has spread to the chest wall and/or skin of the breast. The tumor may have spread to lymph nodes that are clumped together or sticking to other structures, or cancer may have spread to lymph nodes near the breastbone.STAGE IIIC
Stage IIIC describes invasive breast cancer in which: There may be no sign of cancer in the breast or, if there is a tumor, it may be any size and may have spread to the chest wall and/or the skin of the breast. The cancer has spread to lymph nodes above or below the collarbone.The cancer may have spread to lymph nodes or to lymph nodes near the breastbone.
STAGE IV
Stage IV: Stage IV describes invasive breast cancer in which the cancer has spread to other organs of — usually the lungs, liver, bone, or brain.
GRADES
Knowing a breast cancer’s grade is important to understand how fast it’s likely to grow and spread.
What is a breast cancer’s grade?
Cancer cells are given a grade when they are removed from the breast and checked in the lab. The grade is based on how much the cancer cells look like normal cells. The grade is used to help predict your outcome (prognosis) and to help figure out what treatments might work best.
A lower grade number (1) usually means the cancer is slower-growing and less likely to spread.
A higher number (3) means a faster-growing cancer that’s more likely to spread.
Three cancer cell features are studied and each is assigned a score. The scores are then added to get a number between 3 and 9 that is used to get a grade of 1, 2, or 3, which is noted on your pathology report. Sometimes the terms well differentiated, moderately differentiated, and poorly differentiated are used to describe the grade instead of numbers:
Grade 1 or well differentiated (score 3, 4, or 5). The cells are slower-growing, and look more like normal breast tissue.
Grade 2 or moderately differentiated (score 6, 7). The cells are growing at a speed of and look like cells somewhere between grades 1 and 3.
Grade 3 or poorly differentiated (score 8, 9). The cancer cells look very different from normal cells and will probably grow and spread faster.
DCIS is also graded on how abnormal the cancer cells look. Necrosis (areas of dead or dying cancer cells) is also noted. If there is necrosis, it means the tumor is growing quickly.