Tests for Diagnosing IDC

Diagnosing invasive ductal carcinoma usually involves a combination of procedures, including a physical examination and imaging tests.

• Physical examination of the breasts: Your doctor may be able to feel a small lump in the breast during a physical examination. He or she also will feel the lymph nodes under the armpit and above the collarbone to see if there is any swelling or other unusual changes.
• Mammography: Invasive ductal carcinoma is usually found by mammography, a test that obtains x-ray images of the breast. Mammograms are used to screen apparently healthy women for early signs of breast cancer. One key feature of an invasive breast cancer is spiculated margins, which means that on the mammography film, the doctor sees an abnormality with finger-like projections coming out of it. These projections show the “invasion” of the cancer into other tissues.
  
  If a screening mammogram highlights an area of concern, additional mammograms often will be done to gather more information about that area. Mammography will be performed on both breasts.
• Ultrasound bounces sound waves off of the breast to obtain additional images of the tissue. Ultrasound is sometimes used in addition to mammography.
• Breast MRI: MRI, or magnetic resonance imaging, uses magnetic fields, radio waves, and a computer to obtain images of tissues inside the body. In certain cases, a doctor may use breast MRI to gather more information about a suspicious area within the breast.
• Biopsy: If you do have a suspicious mammogram or other imaging test result, your doctor will probably want you to have a biopsy. A biopsy involves taking out some or all of the abnormal-looking tissue for examination by a pathologist (a doctor trained to diagnose cancer from biopsy samples) under a microscope.
  
  When possible, your doctor will usually use one of the quicker, less invasive approaches to biopsy:
  • Fine needle aspiration biopsy involves inserting a very small, hollow needle into the breast. A sample of cells is removed and examined under the microscope. This method leaves no scars.
  • Core needle biopsy inserts a larger needle into the breast to remove several cylinder-shaped 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.
  In cases where the doctor cannot feel the lump, he or she may need to use ultrasound or mammograms to guide the needle to the right location. You may hear this referred to as stereotactic needle biopsy or ultrasound-guided biopsy.
  
  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 removes a small piece of tissue for examination.
  • Excisional biopsy attempts to remove the entire suspicious lump of tissue from the breast.
  Again, if the doctor cannot feel the lump, he or she may need to use mammography or ultrasound to find the right spot. Your doctor also may use a procedure called needle wire localization. Guided by either mammography or ultrasound, the doctor inserts a small hollow needle through the breast skin into the abnormal area. A small wire is placed through the needle and into the area of concern. Then the needle is removed. The doctor can use the wire as a guide in finding the right spot for biopsy.
  
  These surgical biopsies are done only to make the diagnosis. If invasive ductal carcinoma 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, mastectomy.

For more information on all of these tests, visit the Screening & Testing section.