Breast cancer: biopsies to confirm diagnosis
The first test is often the mammogram. This is an X-ray examination of the breasts. A tumor is shown either as a mass or as the presence of small white dots, called “micro-calcifications,” whose number, shape and distribution indicate whether or not cancer is suspected.
Two other imaging tests are sometimes performed in addition to the mammogram.
- The sonogram uses ultrasound technology. It helps determine, for example, whether the lump found in the mammogram is a cyst composed of liquid or a solid tumor.
- More rarely, the physician may request an MRI (magnetic resonance imaging). While far from being systematically used, it may help establish the difference between a benign and malignant lump. It may also be used to check whether the cancer has spread, or if there is local recurrence for individuals who have already been treated for breast cancer.
After imaging, the diagnosis is confirmed by a pathological examination of a fragment of breast tissue. Only examination of a sample under the microscope can confirm with certainty the breast cancer diagnosis. Physicians have several options.
- Fine-needle biopsy: the physician locates the lesion manually and takes a sample using a very fine needle.
- Micro-biopsies with manual or sonogram-assisted location: following a small incision in the skin, the physician takes several micro samples.
- Stereotactic macro-biopsy: the lump is located via X-ray, and six to 12 samples are taken.
These samples are then studied under the microscope to determine whether the lesion is benign or cancerous. In the latter case, the tumor will have to be characterized according to stage, type, and so on.
Following analysis, if the results lead us to believe that the cancer has spread to other parts of the body, additional tests may be indicated, such as chest X-ray, MRI and bone scan.