Breast cancer(DCIS) is an uncontrolled growth of breast cells. To better understand breast cancer, it helps to understand how any cancer can develop.

Cancer occurs as a result of mutations, or abnormal changes, in the genes responsible for regulating the growth of cells and keeping them healthy. The genes are in each cell’s nucleus, which acts as the “control room” of each cell. Normally, the cells in our bodies replace themselves through an orderly process of cell growth: healthy new cells take over as old ones die out. But over time, mutations can “turn on” certain genes and “turn off” others in a cell. That changed cell gains the ability to keep dividing without control or order, producing more cells just like it and forming a tumor.

Causes:

Diagnosing DCIS usually involves a combination of procedures:

• Physical examination of the breasts: Your doctor may be able to feel a small lump in the breast during a physical examination, although a noticeable lump is rare with DCIS. In cases when DCIS cannot be felt during a physical exam, it can often be detected using mammography.
• Mammography: DCIS is usually found by mammography. As old cancer cells die off and pile up, tiny specks of calcium (called “calcifications” or “microcalcifications”) form within the broken-down cells. The mammogram will show the cancer cells inside the ducts as a cluster of these microcalcifications, which appear either as white specks or as a shadow.
• Biopsy: If you do have a suspicious mammogram, your doctor will probably want you to have a biopsy. There are two ways to get a biopsy done with only a little bit of surgery (more invasive biopsies are rarely needed for DCIS):
  • Fine needle aspiration biopsy: A very small, hollow needle is inserted into the breast. A sample of cells is removed and examined under the microscope. This method leaves no scars.
  • Core needle biopsy: A larger needle is inserted to remove several bigger samples of tissue from the area that looks suspicious. In order to get the core needle through the skin, the surgeon must make a tiny incision. This leaves a very tiny scar that is barely visible after a few weeks.

  If a needle biopsy is not able to remove cells or tissue, or it does not give definite results (inconclusive), a more involved biopsy may be necessary. These biopsies are more like regular surgery than needle biopsies:

  • Incisional biopsy: Incisional biopsy removes a small piece of tissue for examination.
  • Excisional biopsy: Excisional biopsy attempts to remove the entire suspicious lump of tissue from the breast.

Biopsies are done only to make the diagnosis. If DCIS is diagnosed, more surgery is needed to ensure all of the cancer is removed along with “clear margins,” which means that a border of healthy tissue around the cancer is also removed. Usually this means having lumpectomy, or in some cases (a large area of DCIS, for example), mastectomy.

After the biopsy, the pathologist analyzes the piece of breast tissue and reports back on the:

• type and grade of the DCIS: how abnormal the cells look when compared with normal breast cells, and how fast they are growing
• hormone-receptor status: Whether or not the cancer cells have receptors (proteins in a cell that receive messages from hormones) for the hormones estrogen and/or progesterone. If estrogen and/or progesterone receptors are present, this means that the cancer cells’ growth is fueled by these hormones.

Type and grade of DCIS

All DCIS is considered stage 0 breast cancer — the earliest stage possible. “Stage” describes how far the cancer has spread beyond the site of the original tumor. Even though DCIS is always considered stage 0, it can be any size and be located in any number of areas inside the breast.

Knowing the type and grade of DCIS can help you and your doctor decide on the best treatment for you.

When a pathologist looks at the tissue removed during the biopsy, he or she determines whether or not any abnormal cells are present. If abnormal cells are present, the pathologist will note how different the cells look compared with normal, healthy breast cells. The image shows the range of possible findings, from normal cells all the way to invasive ductal cancer.

Breast cancer: Stages

• Normal cells
• Ductal hyperplasia or “overgrowth” means that too many cells are present.
• Atypical ductal hyperplasia means that there are too many cells (hyperplasia) and they are starting to take on an abnormal appearance (atypical or “not typical”).
• Ductal carcinoma in situ (DCIS) means that there are too many cells and they have the features of cancer, but they are still confined to the inside of the duct. (DCIS is stage 0 breast cancer.)
• DCIS-MI (DCIS with microinvasion) means that a few of the cancer cells have started to break through the wall of the duct. DCIS-MI is stage I breast cancer.
• Invasive ductal cancer (IDC) means that the cancer cells have broken beyond the breast duct. The breast cancer is no longer a DCIS but an invasive ductal carcinoma, the most common type of breast cancer. IDC can be diagnosed at any stage from I-IV.

Symptoms:

DCIS generally has no signs or symptoms. A small number of people may have a lump in the breast or some discharge coming out of the nipple. About 80% of DCIS cases are found by mammography.

Treatments:

• Lumpectomy followed by radiation therapy: This is the most common treatment for DCIS. Lumpectomy is sometimes called breast-conserving treatment because most of the breast is saved.
• Mastectomy: Mastectomy, or removal of the breast, is recommended in some cases.
• Lumpectomy alone(radiation therapy)
• Hormonal therapy after surgery: These treatments, which block or lower the amount of estrogen in the body, are typically used if the DCIS tests positive for hormone receptors.

Chemotherapy, a form of treatment that sends anti-cancer medications throughout the body, is generally not needed for DCIS. DCIS is non-invasive and remains within the breast duct, so there is no need to treat cancer cells that might have traveled to other areas of the body.