Breast Cancer Detection
Currently, mammography is the most effective technology available for breast cancer screening. But, aside from the conventional mammography, there are several techniques that can be used for screening. These techniques are:
- Digital Mammography
- Computer-Aided Detection
- PET scan
- Electrical Impedance Scanning
- Ductal Lavage
Ultrasound: The ultrasound, also referred to as sonography, is a technique in which high-frequency sound waves, unhearable for humans, are bounced off tissues and internal organs. The echoes generated produce a picture known as a sonogram. This form of imaging is commonly used to distinguish between solid tumors and cysts. An ultrasound is sometimes also used to examine lumps that are difficult to see on a mammogram. The ultrasound can also be used as part of other diagnostic procedures, such as needle biopsies (the removal of tissue, or fluid, through the use of needles). Ultrasounds are not used for routine breast exams, because this technique is not suitable for detecting early signs of cancer.
Digital Mammography: Compared to the conventional mammograms, digital mammograms use computerized images instead of x-ray film. Before printed on film, the images are displayed on a monitor, where they can be modified (enhanced, magnified, etc.). The patient won’t notice a difference between the conventional and digital mammogram, as they are both performed using the same procedure. Digital mammography has a few advantages over conventional mammography. As previously indicated the images are electronically stored, this digital aspect of the mammograms makes long-distance consultations easier. There is also an improved accuracy with the digital mammograms, which decreases the number of follow-ups required. Despite these benefits, digital mammography does not increase the number of breast cancer tumors found in women.
Computer-Aided Detection: Computer-aided detection (CAD) is the use of computers to bring suspicious areas on a mammogram to the radiologist’s attention. It is used after the radiologist has done the initial review of the mammogram, and is performed by scanning the mammogram into the computer.
MRI: MRI (Magnetic Resonance Imaging) is the creation of detailed pictures of areas inside the body through the use of a magnet, this form of imaging does not use radiation. The MRI of a breast is conducted by placing the patient on her stomach, on a scanning table. The patient’s breasts will hang into a hollow in the table, which contains coils which detect magnetic signals. The table is then moved into a tube-like machine that contains a magnet. The first series of picture are then taken, upon which the patient sometimes receives the contrast agent. The contrast agent can be used to improve the visibility of a tumor. The entire session may take about an hour.
PET scan: A PET (Positron Emission Tomography) scan is a computerized image of chemical changes taking place in human tissue. Patients are given an injection of a combination of sugar and a small amount of radioactive material. This radioactive sugar helps in locating a tumor, because cancer cells absorb sugar faster than other tissues in the body.After the radioactive substance has been injected, the patients lies still on a table for 45 minutes while she moves through the PET scanner 6 to 7 times. This time period allows the drug to circulate the body, and if a tumor is present the sugar will accumulate in it. PET scans are more accurate in detecting larger and/or aggressive tumors than they are in locating small and/or less aggressive ones.
Electrical Impedance Scanning: Human tissue has different electrical impedance levels (the speed of electricity through material). Breast tissue that is cancerous has a much lower electrical impedance (conducts electricity better) than normal breast tissue. The EIS is done by placing an electrode patch on the patient’s arm, and passing a very small current into the body. The current travels through the breasts, where it is measured by the scanning probe, which is placed over the breast. This gives a computerized image of the breasts; tumors show up as bright white spots on the screen.At this time, mammograms are the most effective tool we have to detect changes in the breast that may be cancer. In women at high risk of breast cancer, researchers are studying the combination of mammograms and ultrasound. Researchers are also exploring positron emission tomography (PET) and other ways to make detailed pictures of breast tissue.
Ductal Lavage: Ductal lavage is an investigational technique for collecting samples of cells from breast ducts for analysis. The physician introduces a salt water solution into a milk duct, through a thin tube which is inserted into the opening of the duct on the surface of the nipple. The doctor then extracts fluids from the duct, which are then checked for indications of cancer.
Breast Cancer Staging
To plan your treatment, your doctor needs to know how far your breast cancer has developed. The different stages of breast cancer are based on the size of the tumor, and whether the cancer has spread. Staging is done through x-rays, examination of the lymph nodes, and other clinical tests. These tests can show whether the cancer has spread and, if so, to what parts of the body. The stage is often not known until the tumor has been removed.
Breast cancer is most commonly staged on the basis of the American Join Committee on Cancer (AJCC) TNM System. This system stages breast cancer based on results from either physical exams, biopsies, or imaging tests, plus findings after surgery. The pathologic form of staging is more accurate than the clinical form, because it gives doctors the ability to exam the cancer more extensively.
Breast Cancer Stages: According to the TNM system there are 5 stages of cancer, stages 0 to IV. Stage 0 being the non-invasive cancer, stage I the least advanced, and stage IV the most advanced.
Stage 0: Stage 0 is referred to as ductal carcinoma in situ (DCIS); it is the earliest form of breast cancer. When a woman is diagnosed with stage 0, the cancer cells have not yet invaded into the surrounding fatty breast tissue.
Lobular carcinoma in situ (LCIS) is sometimes also categorized as stage 0, however, many oncologists do not believe that it is a true form of breast cancer. In LCIS, abnormal cells grow within the lobules, but do not penetrate the lobules’ wall.
Paget disease of the nipple (without a tumor mass) is also categorized as stage 0. In all cases the cancer has not spread to lymph nodes or other tissues.
Stage I: With stage I the tumor is smaller than 2 cm (3/4 in.) in diameter, and has not spread to the lymph nodes or other, distant, tissue.
Stage IIA: There are many classifications for Stage IIA breast cancer, any of the following applies:
- The tumor is less than 2cm in diameter, or not found, and has spread to 1-3 axillary lymph nodes
- The tumor is less than 2 cm in diameter, or not found, and tiny amounts of cancer can be found in internal mammary lymph nodes on sentinel lymph node biopsy
- The tumor is less than 2 cm in diameter, and has spread to 1-3 axillary lymph nodes, and tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy
- The tumor is larger than 2 cm but smaller than 5cm in diameter, but has not spread to the lymph nodes.
Stage IIB: Similar to stage IIA, stage IIB cancer can have any of the following characteristics:
- The tumor is larger than 2 cm, but less than 5 in diameter. It has also spread to 1-3 axillary lymph nodes and/or tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy
- The tumor is larger than 5 cm in diameter but does not grow into the chest wall or surrounding tissue, and has not spread to the lymph nodes.
- The tumor is not more than 5cm in diameter, or cannot be found. It has furthermore spread to 4 to 9 axillary lymph nodes, or it has enlarged the internal mammary lymph nodes.
- The tumor is larger than 5 cm in diameter, but has not grown into the surrounding tissue. It has spread to 1-9 of the axillary nodes, or to internal mammary nodes.
Stage IIIB: With stage IIIB cancer, the tumor has grown into the chest wall or skin, and one of the following applies:
- It has not spread to the lymph nodes.
- It has spread to 1-3 axillary lymph nodes and/or tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy.
- It has spread to 4-9 axillary lymph nodes, or it has enlarged the internal mammary lymph nodes
Inflammatory breast cancer is also classified as stage IIIB unless it has spread to distant lymph nodes or organs, in which case it would be stage IV.
Stage IIIC: Stage IIIC tumors are of any size, or cannot be found, and one of the following applies:
- The cancer has spread to 10 or more axillary lymph nodes.
- The cancer has spread to the lymph nodes under the collarbone.
- The cancer has spread to the lymph nodes above the collarbone.
- The cancer involves axillary lymph nodes and has enlarged the internal mammary lymph nodes.
- Cancer involves 4 or more axillary lymph nodes, and tiny amounts of cancer are found in internal mammary lymph nodes on sentinel lymph node biopsy.
Stage IV: The cancer can be any size and may or may not have spread to nearby lymph nodes. It has spread to lymph nodes far from the breast, and distant organs; the most common sites being: the bone, liver, brain, and lung.