Breast cancer basics

Though many people think of breast cancer as one disease, there are actually more than a dozen different types. Check out below for information on four of the most common types, how they’re diagnosed and what they mean for patients.

Infiltrating Ductal Carcinoma: IDC is the most common type of breast cancer - it represents as many as 80 percent of all invasive cancers. It first develops in the milk duct, then breaks through the ductal wall and spreads to the surrounding fatty tissue. From there, it can spread to the lymph nodes and other parts of the body. Women can sometimes feel IDC lumps during self-exams, although they’re usually found with mammography. Treatment often includes lumpectomy or mastectomy and, depending on if and how far the cancer has spread, chemotherapy and/or radiation.

Ductal Carcinoma In Situ: DCIS, a condition in which cancerous cells develop in the milk ducts, is the most common type of noninvasive breast cancer; it accounts for about 20 percent of all breast cancer diagnoses. It’s typically detected by a mammogram, and patients generally have a choice between two treatments: mastectomy or a lumpectomy followed by radiation. Because the cancer has not spread, the prognosis is excellent.

Invasive (or Infiltrating) Lobular Carcinoma: ILC begins in the lobules (milk-producing glands) and then spreads to surrounding tissues. Because it’s more difficult to see on a mammogram, doctors often use ultrasound and MRI after a mammogram reveals an abnormality in the breast. Patients have a better prognosis than those with IDC because this type of cancer tends to spread slowly, and it also responds well to therapy that either blocks estrogen receptors in cancer cells or suppresses the body’s estrogen production. Hormone therapy is generally used in conjunction with lumpectomy or mastectomy and radiation or chemotherapy.

Medullary Carcinoma: This type of cancer is characterized by a well-defined boundary between the cancerous cells and normal breast cells; that boundary is defined by immune system cells, which may be why cancerous cells rarely spread to lymph nodes. It’s most frequently found in women in their late 40s and 50s. Some doctors opt only for surgery to remove the tumor, while others recommend a more aggressive treatment regimen.