What Is Breast Cancer?
Breast cancer is when the cells under one or both breasts grow out of control. Those cells may spread beyond your breasts. When that happens, the cancer is called metastatic.
Breast cancer usually begins either in your glands that make milk (called lobular carcinoma) or the ducts that carry it to the nipple (called ductal carcinoma). It can grow larger in your breast and spread to nearby lymph nodes or through your bloodstream to other organs. The cancer may grow and invade tissue around your breast, such as your skin or chest wall.
Breast Cancer Symptoms
A lump under the breast, which you may or may not feel, is usually the first sign of breast cancer. When you get a mammogram, your doctor may notice this lump. You also may not notice any signs in the early stages.
The symptoms of breast cancer can include:
- A lump or thickened area in or near your breast or underarm that lasts through your period
- A mass or lump, even if it feels as small as a pea
- A change in your breast’s size, shape, or curve
- Nipple discharge that can be bloody or clear
- Changes in the skin of your breast or your nipple. It could be dimpled, puckered, scaly, or inflamed.
- Red skin on your breast or nipple
- Changes in the shape or position of your nipple
- An area that’s different from any other area on either breast
- A hard, marble-sized spot under your skin
Types of Breast Cancer
Some of the most common types of breast cancer include:
In situ cancers. These types haven’t spread past the duct or lobule where they started.
- Ductal carcinoma in situ (DCIS). This is ductal carcinoma in its earliest stage (stage 0). In this case, the disease is still in the milk ducts. But if you don’t treat this type, it can become invasive. It’s often curable.
- Lobular carcinoma in situ (LCIS). This is found only in the lobules, which produce breast milk. It isn’t a true cancer, but it means you’re more likely to get breast cancer later. If you have it, get regular breast exams and mammograms.
- Related:Early Warning Signs of Breast Cancer
Invasive cancers. These have spread or invaded the surrounding breast tissue.
- Invasive or infiltrating ductal carcinoma (IDC). This cancer starts in the milk ducts. It breaks through the wall of the duct and invades the fatty tissue of the breast. It’s the most common form, accounting for 80% of invasive cases.
- Invasive lobular carcinoma (ILC). This cancer starts in the lobules but spreads to surrounding tissues or other body parts. It accounts for about 10% of invasive breast cancers. Subtypes of this invasive breast cancer include:
- Adenoid cystic (or adenocystic) carcinoma. These are similar to cells found in your salivary glands and saliva.
- Low-grade adenosquamous carcinoma (a type of metaplastic carcinoma). This rare tumor is usually slow-growing and often mistaken for other types.
- Medullary carcinoma. The tumors in this rare type are a soft, squishy mass that looks like part of your brain called the medulla.
- Mucinous carcinoma. Tumors in this rare type float in a pool of mucin, part of the slippery, slimy stuff that makes up mucus.
- Papillary carcinoma. Fingerlike projections set these tumors apart. This rare type usually affects women who’ve been through menopause.
- Triple-negative breast cancer. This type happens when the cancer cells don’t have the right hormonal receptors. It makes up almost 15% of all breast cancers. It can happen at any age, but generally in women under 40.
- Tubular carcinoma. The tumors are slow-growing and tube-shaped.
