How is breast cancer diagnosed?
Diagnosis of breast cancer is different from breast cancer screening. Screening is performed to detect breast abnormality (breast cancer) in its pre symptomatic phase , whereas diagnosis is performed to confirm whether an abnormality that has already been detected, is cancerous or not. Contrary to popular opinion, an abnormal finding on a screening mammogram or the self-discovery of a lump or other breast changes does not necessarily confirm that someone has breast cancer.
There is only one way to confirm if an abnormal finding is cancerous – by performing a breast biopsy and its histopathological examination.
What are the steps involved in the diagnosis of breast cancer?
In our knowledge article on breast cancer screening, we have examined the following types of imaging tests that help doctors detect an early abnormality in the absence of symptoms:
Clinical breast examination: A doctor will check both of your breasts and lymph nodes in your underarm area, to feel any lumps or other abnormalities.
Screening mammogram: A mammogram is an X-ray picture of the breast. They are commonly used in breast cancer screening. If an abnormality is seen during a screening mammogram, doctors generally recommend a diagnostic mammogram to further inspect the problem.
Breast MRI: MRI scan of breast is usually recommended for patients who exhibit doubtful lesions or multiple small lesions seen on breast mammograms, and women with high risk genes (BRCA 1/2).
After the detection of abnormalities, either during routine screening or during a doctor-advised checkup, the following tests are usually performed to further diagnose and confirm breast cancer. Please note that the diagnosis remains incomplete without a breast biopsy.
Further diagnostic testing:
Diagnostic mammogram
This is an advanced form of a mammogram. To generate this image, the patient’s breasts are put, one at a time, between two special plates and compressed (pressed down) between these plates by an X-ray machine momentarily, while the X-rays are taken. A minimum of two views of each breast are taken.
Both the mammography and the compression are performed by a specially trained radiographer (medical imaging technologist). While the compression might be uncomfortable for some women and sometimes painful, it lasts only for a few seconds. Without compression, the diagnostic mammogram X-rays can become blurry, which makes it hard to confirm the nature of any abnormality. The act of compression also reduces the total amount of radiation needed for a diagnostic mammogram.
Breast ultrasonography (USG)
This process uses sound waves to render images of structures deep within the breast area. Ultrasound technology can be used to confirm whether a new breast lump is actually a solid mass (potentially cancerous) or just a fluid-filled cyst. Breast USG is helpful in young females with dense breasts.
Breast biopsy
This is the gold standard test for confirming breast cancer. After all abnormalities found through either self exams or screening are inspected using various scans, if a doctor suspects the presence of cancer, a biopsy is advised. During a breast biopsy, doctors use a special needle to extract a piece of tissue from the area of concern. Sometimes during a breast biopsy, a small metal marker is left at the site of suspicion within the breast, so that the area can be easily identified later for future imaging investigations.
Biopsy samples (tissue samples extracted during a biopsy) are then sent to a laboratory for a thorough analysis, where experts determine whether the cells in that tissue sample are cancerous. A biopsy sample can also help in ascertaining the aggressiveness of breast cancer, and to understand whether hormone receptors are present in a specific patient.
A biopsy is also the first step towards establishing the overall disease prognosis. This information will help any oncologist (medical, radiation and surgical oncology experts) to determine the best course of treatment.