Tests for Diagnosis of Breast Cancer
Written by : Dr.Kishore Kumar Das, MD
Breast cancer diagnosis depends on a number of tests. Since each test needs to be correlated with each other, it can take quite some time for an accurate diagnosis to come in. So, a good knowledge of the various tests is essential for women suffering from breast cancer.
Breast Self Examination:
It is essential that every woman after the age of 40 years undertake a breast self-examination once a month. This will help to identify any lumps, pain or other symptoms in the breast. While all lumps and pain are not due to breast cancer, it is possible that some breast cancers may be diagnosed by self examination in some women. Unfortunately, many breast cancers go undetected even with a breast self examination.
Mammograms: A non-invasive medical test like a mammography is usually used as a screening test for breast cancer. All women above the age of 40 years should get a yearly mammogram. Women with a history of breast cancer in a first degree relative (mother or sister) should get mammograms even earlier in life. In most woman, breast cancers like Ductal cancer in situ (DCIS) and Invasive Ductal Cancer (IDC) are usually first diagnosed in a routine mammography.
Ultrasound: A mass or lump in the breast is the commonest symptom of a breast cancer. If this is detected by a mammography, it needs to be followed up by an ultrasound. Since ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels. This helps detect small breast cancers that may not be seen on a mammogram.
Ultrasound Guided Biopsy: In cases where a suspicious mass is detected, the patient needs to undergo a biopsy. There are different types of biopsies depending on the size and the site of the mass. The commonest biopsy is an ultrasound guided fine needle biopsy (Fine Needle Aspiration Cytology - FNAC) in which a needle is inserted into the mass and a core of tissue taken out while watching the process in realtime on a monitor on the ultrasound machine. This ensures accuracy of the procedure.
Hormone Receptor test: Breast tissues obtained by biopsy are sent for hormone receptor tests. Cancers which are estrogen or progesterone receptor positive respond better to medicines like tamoxifen which can block the receptors.
MRI: MRI or Magnetic resonance imaging of the breast is a supplemental tool for detecting and staging breast cancer and other breast abnormalities. It is not a replacement for either mammography or ultrasound. It is done to evaluate lumps or masses detected by mammography or ultrasounds. It can also differentiate between recurrent tumors and scar tissues, spread of the breast cancer and to assess the efficacy of treatment procedures. It is particularly helpful in differentiating between DCIS and IDC and between LCIS and ILC.
CT Scan: A CT scan is not very effective in the diagnosis of breast cancer. But it can still assist in evaluation of breast cancer, especially after surgery or chemotherapy.
PET: PET can show whether or not a lump in the breast is benign or malignant, even without a biopsy. PET can detect the uptake of glucose by the cells. Since metabolic rate and energy requirement of malignant cells are much more than normal cells, the cells show up as 'hot spots' on the PET scan. PET scans can also diagnose metastasis or spread of the cancerous cells, can show recurrent disease and also help evaluate response to therapy.
Biopsy of the Skin: A biopsy of the skin is necessary in the diagnosis of Paget's disease of the breast and Inflammatory breast Cancer.
Genetic testing: All women with breast cancer must undergo genetic testing, more so if the woman already has a a family history of breast cancer. Research has shown that breast cancer in a first degree relative (mother, sister) increases the risks of breast cancer by almost 10%. The common genes involved are BRCA1 and BRCA2. Other genes are HER2, p53 gene, ATM gene, CHEK2 and PTEN.
Blood Marker tests: Many cancers produce a specific protein in the blood that serves as a 'marker' for the cancer. Breast cancer markers are CA 15.3, TRU-QUANT, CA 27.29 and CA125. Blood tests for markers may be done before treatment, during treatment to check for response to the treatment procedures and after treatmeent to check for recovery as well as for recurrence of breast cancer.
Bone Scans: Bone scans, also called bone scintigraphy, is a special type of nuclear medicine procedure that uses small amounts of radioactive material to determine whether breast cancer has traveled to the bones. It is done before treatment as well as after treatment if bone pain is present to check for spread to the bones.
Blood Cell tests: Blood cell counts, especially white blood cells levels need to be checked during chemotherapy. Chemotherapy can considerably reduce the WBC level. A low WBC level can lower the immune level of the woman, making her prone to develop various infections. Red blood cells as well as the platelet level also need to be checked from time to time.
Blood Chemistries: Blood chemistry helps determine the health of organs like the liver and the kidneys which may be affected by the different treatment procedures.