The term “breast cancer” does not describe a single type of cancer, but rather several forms of a disease that can develop in areas of the breast. The American Cancer Society says breast cancer type is determined by the specific cells in the breast that become cancerous. There are many different types of breast cancer, and the medical community’s understanding of the disease is based on decades of research and millions of patients treated.
In 2001, Dr. Charles Perou first classified breast cancer into subtypes based on genomic patterns. The Breast Cancer Research Foundation says breast cancer is broadly divided into two types: non-invasive breast cancers and invasive breast cancers. Non-invasive breast cancers are called Stage 0 breast cancers or carcinomas in situ. These are thought to be the precursors to breast cancer, says the BCRF. While non-invasive breast cancers are not initially life-threatening, if left untreated, they can develop into invasive breast cancers, which can be fatal.
Here is a look at some of the different types of breast cancer.
• Invasive ductal carcinoma: This is the most common type of breast cancer, advises the National Breast Cancer Foundation, Inc.. Invasive ductal carcinoma accounts for 70 to 80 percent of all breast cancer diagnoses in women and men. This cancer forms in the milk ducts and spreads beyond.
• Invasive lobular carcinoma: This is the second most common type of breast cancer, accounting for 10 to 15 percent of diagnoses, says the BCRF. Invasive lobular carcinoma originates in the milk-producing glands of the breast known as lobules. Tumors that form due to invasive lobular carcinoma more commonly grow in lines in the breast rather than in lumps, so they present differently on a mammogram.
• Inflammatory breast cancer: Inflammatory breast cancer is a rare, fast-growing type of breast cancer. The inflammatory name comes from the appearance of the skin of the breast. It looks red and inflamed, which is caused by breast cancer cells blocking lymph channels in the breast and skin, says Breast Cancer Now, a research and support charity.
• Tripe-negative breast cancer: The NBCF says a diagnosis of triple-negative breast cancer means the three most common types of receptors known to cause most breast cancer growths are not present in the cancer tumor. These receptors are estrogen, progesterone and the HER2/neu gene. Since the tumor cells lack necessary receptors, certain treatments like hormone therapy and drugs that target these receptors are ineffective. Chemotherapy is still an option.
• Metastatic breast cancer: This type of breast cancer is also known as Stage IV breast cancer. Metastatic breast cancer originates in an area of the breast, but spreads (metastasizes) to another part of the body, most commonly the bones, lungs, brain, or liver, indicates BreastCancer.org.
