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CloseDiagnosis of Breast Cancer
Diagnostic Evaluation of Breast Cancer
Laboratory Evaluation
Complete blood count (CBC) helps to determine the presence of infection (usually reflected in an elevated white blood cell count) or anemia (low red blood cell count)
Ductal Lavage - This is an experimental test developed for women who have no symptoms of breast cancer but are at very high risk for breast cancer. Gentle suction is applied to the nipple to draw fluid from the milk ducts up to the nipple surface. The fluid droplets that appear help locate the milk ducts' natural openings on the surface of the nipple. A small catheter is then inserted into a milk duct and saline solution is slowly delivered through the catheter to gently "rinse" the duct and collect cells. This fluid is withdrawn through the catheter and sent to a lab, where the cells are viewed under a microscope. More studies are needed to better define the usefulness of this test.
Radiological Evaluation of Breast Cancer
Mammography
Mammography is a low-dose X-ray of the breasts that produce an image of the breasts known as a mammogram. Both screen-film mammography and full-field mammography use x-rays to obtain images. With screen-film mammography the image is captured on film; with full-field digital mammography the image is captured digitally. Approximately 95% of women with abnormalities on screening mammograms do not have breast cancer.
The American College of Radiology (ACR) has developed a standard way of describing mammogram findings. In this system, the results are given a code (numbered 0 through 6). This system is called the Breast Imaging Reporting and Data System (BIRADS). Having a standard way of reporting mammogram results lets doctors use a consistent language and ensures better follow up of suspicious findings.
The BIRADS system for describing mammogram findings includes:
Category 0: "Additional Imaging Evaluation and/or Comparison to Prior Mammograms Is Needed" - A possible abnormality may not be completely seen or defined and will need more tests, such as the use of spot compression, magnification views, special mammogram views, or ultrasound.
Category 1: "Negative" - In this case, there is no significant abnormality to report. The breasts appear the same (symmetrical) with no masses, architectural distortion, or suspicious calcifications.
Category 2: "Benign (Non-cancerous) Finding" - This is also a negative mammogram, but the reporting doctor chooses to describe a finding known to be benign, such as benign calcifications, intramammary lymph nodes, or calcified fibroadenomas. This ensures that others viewing the mammogram will not misinterpret this benign finding as suspicious. This finding is recorded in the mammogram report for use in future mammogram assessments.
Category 3: "Probably Benign Finding - Follow-up in a Short Time Frame Is Suggested" - The findings placed in this category have a very high probability (greater than 98%) of being benign. Follow-up with repeat imaging is usually done in 6 months and regularly thereafter until the finding is known to be stable (usually at least 2 years). This approach helps avoid unnecessary biopsies but allows for early diagnosis of a cancer should the suspicious area change over time.
Category 4: "Suspicious Abnormality - Biopsy Should Be Considered" - Findings in this category do not definitely look like cancer but could be cancer. The radiologist has sufficient concern to recommend a biopsy.
Category 5: "Highly Suggestive of Malignancy" - The findings in this category look like cancer and have a high probability (at least 95%) of being cancer. Biopsy is very strongly recommended.
Category 6: "Known Biopsy-Proven Malignancy" - This category is only used for findings on a mammogram that have already been determined to be cancerous by a previous biopsy.
Other Imaging Modalities for Breast Cancer
Ultrasound (sonogram) - This technique uses high-frequency sound waves to create an image and is frequently used as a targeted diagnostic examination to focus on a specific area of concern to distinguish between cyst and solid masses, and between benign and malignant masses.
Magnetic Resonance Imaging (MRI) - this imagning technique uses radiofrequency waves and a strong magnetic field rather than x-rays to provide remarkably clear and detailed pictures of internal organs and tissues. While MRI is generally used only for diagnosis of a suspected lesion seen on mammography, it may be helpful for women for whom mammography is not optimal, such as young women at high-risk of breast cancer because of BRCA mutations. It is also useful for identification of primary lesions in non-palpable lesions and axillary metastases with no evidence of primary focus, and for the assessment of response to neoadjuvant therapy.
Ductogram - Also called a galactogram, this is a type of x-ray test in which a fine plastic tube is placed into the opening of the duct into the nipple. A small amount of dye is injected, which outlines the shape of the duct on an x-ray picture and will show whether there is a mass inside the duct.
Positron Emission Tomography (PET Scan) - This technique is presently used to discover undetected metastatic lesions in distant organs and can assess the status of axillary lymph nodes prior to surgery. However, PET may fail to identify low-grade lesions and tumors less than 5mm in size.
Scintimammography - This is a type of nuclear breast imaging that may be used to investigate a breast abnormality found on mammography. Nuclear medicine breast imaging involves injecting a radioactive tracer (dye) which accumulates differently in cancerous and non-cancerous tissues - normal tissue will only accumulate a small amount of the radioactive tracer, but cancer cells tend to take up more of the dye. After the radioactive tracer has been injected, the patient is instructed to lie face down on a special table where a special camera is used to capture images of the breast from several angles. The procedure takes approximately 45-60 minutes to perform.
Thermomagraphy - This procedure uses a special heat-sensing camera to measure the temperature on the surface of the breast with the thought that the temperature rises in areas with increased blood flow and metabolism, which could signify a tumor. Thermography is not thought to be an effective screening tool for the early detection of breast cancer and can not be used as a replacement for mammograms. Researchers are attempting to improve the procedure to enhance its usefulness in the future.
Electrical Impedance Imaging - This procedure assesses the electrical conductivity of the breast, based on the idea that breast cancer cells conduct electricity better. It involves passing a very small electrical current through the body and detecting it on the skin of the breast with a small probe (similar to an ultrasound probe). The test does not use radiation or require breast compression. This test has received FDA approval to be used as a diagnostic aid in helping classify tumors detected by mammography. However, it has not undergone enough clinical testing to recommend its use in breast cancer screening.
Biopsy for Suspected Breast Cancer
A biopsy is performed to remove a tissue sample for examination under a microscope when a suspicious lesion is found on mammogram, ultrasound or physical examination. There are several types of biopsies, and each has advantages and disadvantages. The choice of which type of biopsy procedure to use depends on the individual situation. Some of the deciding factors include:
- Size of the lesion
- How suspicious the lesion appears
- Where the lesion is located in the breast
- How many lesions are present
- If co-existing medical problems are present
- Personal preference of the patient
- Experience of the surgeon
Approaches to Breast Biopsy
The options for performing a breast biopsy include:
Fine needle aspiration biopsy (FNAB) - This type of biopsy uses a very thin needle which is guided into the area of the breast abnormality. If the lump can not be felt easily, the doctor might use ultrasound or a method called stereotactic needle biopsy to guide the needle. With ultrasound, the doctor can watch the needle on a screen as it moves toward and into the mass. For stereotactic needle biopsy, computers map the exact location of the mass using mammograms taken from two angles. Once the needle is in place, fluid or small tissue fragments are drawn out. These samples are then sent to the lab, where they are examined under the microscope. Microscopic examination of FNAB samples can tell whether most breast abnormalities are benign or cancerous. In some cases, FNAB does not provide a clear answer and another type of biopsy is needed.
Triple Test - This is not an actual test or procedure. It is a way of correlating the results of the breast physical examination, mammogram, and the FNA biopsy. If all three of these appear benign, the lesion can indeed be considered to be benign with about 98% accuracy. If any one of these is in disagreement, more tests (needle core biopsy or surgical biopsy) should be done.
Core needle biopsy (CNB): The needle used in a core biopsy is larger than that used in FNA biopsy. It removes a small cylinder of tissue (about 1/16 inch in diameter and 1/2 inch long) from a breast abnormality. The biopsy is done with local anesthesia in the doctor's office. As with FNA biopsy, a core biopsy can sample abnormalities felt by your doctor as well as smaller ones pinpointed by ultrasound or stereotactic methods. Two types of special devices used for taking a core biopsy are:
Mammotome - During a Mammotome biopsy, also called a vacuum-assisted biopsy, a surgeon inserts a small tube into the breast tissue (under local anesthesia) and uses suction to draw a cylinder of breast tissue into the tube, and a small rotating knife cuts and removes the tissue (cores) for examination.
Advanced Breast Biopsy Instrument (ABBI) uses a rotating circular knife to remove a larger cylinder of tissue for examination. The ABBI procedure removes more tissue than FNAB, CNB, or the Mammotome.
Surgical biopsy - In some cases, surgery may be needed to remove all or part of the lump for examination under a microscope. An excisional biopsy is used to remove the whole lesion (breast abnormality such as a lump or area containing calcifications) as well as a surrounding margin of normal appearing breast tissue. This biopsy can be done in the hospital outpatient department with local anesthesia or sometimes in your doctor's office.
Wire Localization may be utilized during an excisional breast biopsy of a small lump that is hard to locate by touch or in area that looks suspicious on the mammogram but does not have a distinct lump. After numbing the area with local anesthesia, a thin hollow needle is placed into the breast and x-ray pictures are taken to guide the needle to the suspicious area. A thin wire is placed through the center of the needle. A small hook at the end of the wire keeps it in place. The hollow needle is then removed, and the surgeon uses the wire as a guide to locate the abnormal area to be removed.
Axillary Node Dissection - The axillary lymph nodes are located under the arm. Axillary node dissection is performed to determine if cancer has spread beyond the breast. This procedure may be done at the same time as a lumpectomy or a mastectomy or may be scheduled following a positive biopsy. Axillary node dissection is performed under general anesthesia and requires an incision under the arm for removal of fatty tissue in which 10 to 20 lymph nodes are embedded. The incision is sutured and a drain may be put in to remove excess fluid. The procedure takes between 1 and 2 hours and usually requires at least one night in the hospital. Side effects may include pain, nerve damage, and lymphedema (swelling of the arm on the affected side).
Sentinel Lymph Node Biopsy - The sentinel node is the first lymph node that filters fluid from the breast. It is believed that malignant cells reach the sentinel node first and that this lymph node is more likely to contain cancer cells if the cancer has spread. Sentinel node biopsy involves injecting a radioactive tracer and/or blue dye into and around the tumor. With a small, hand-held Geiger counter, the surgeon tracks the path the tracer takes as it travels away from the breast and under the arm to the first lymph node. Once located, the sentinel node is removed through a small incision and sent to the laboratory for diagnosis.
If the results are negative, it is assumed that the cancer has not spread and there is no need for further surgery. If the sentinel node is positive, the surgeon may perform an axillary node dissection to assess how many other lymph nodes are affected. The procedure is often performed in conjunction with lumpectomy (removal of the suspicious lump).
Because sentinel node biopsy removes fewer lymph nodes than axillary lymph node dissection, many patients have no side effects. However, 5% of patients who undergo this procedure develop a condition called lymphedema which causes swelling of the arm on the affected side. Sometimes, the swelling is temporary, but sometimes it can persist.