Breast Cancer Diagnosis, Part 2
Breast surgery for invasive breast cancer includes examination of the lymph nodes under the arm (axilla). Knowing whether or not there is any cancer in the lymph nodes and how many lymph nodes contain cancer are factors in the patient’s prognosis. Higher numbers of involved lymph nodes are associated with a higher risk of cancer having spread. One way to get this information is to do a complete axillary dissection, meaning that doctors remove all the nodes located under the arm and examine them. Approximately 20 to 30 percent of women who have had a complete axillary dissection may be susceptible to a condition of chronic swelling of the arm known as lymphedema. This may occur shortly after the surgery or even up to ten years later. (Radiation to the underarm area may also increase the risk.) For many women, especially those with small breast cancers, all the lymph nodes will be free of tumor. These women could be spared from having a complete axillary dissection with a more recent procedure known as sentinel node biopsy.
Sentinel node procedure is another component of the minimally invasive approach to breast cancer surgery. In the sentinel node procedure, the “leader,” or sentinel lymph node, is examined first. This axillary node is identified after a radioactive material and/or a blue dye are injected into the breast. Studies have shown that if the sentinel lymph node is free of tumor cells, it is unlikely that other lymph nodes are involved; and when this is the case, it is not necessary to remove the rest of the underarm lymph nodes. However, if cancer cells are found in the sentinel lymph node, then the rest of the lymph nodes should be removed and examined for tumor cells. In general, the sentinel lymph node biopsy is not needed in noninvasive breast cancer (ductal carcinoma in situ, or DCIS), although certain circumstances exist in which the treatment team may believe it is appropriate.
A number of unresolved questions remain about sentinel node procedure. For example, diagnostic methods are now so sophisticated that it is now possible to identify just one single cancer cell in a lymph node. But what does this mean? Do these patients have as high a risk of relapse as patients with a lymph node that is entirely replaced by tumor? How important is it to remove additional lymph nodes if the sentinel lymph node is involved but no treatment decisions will change based on the results? For example, if the same chemotherapy is recommended if there is one lymph node involved as opposed to several, then why do the additional surgery? We hope that several large, ongoing clinical research trials will answer these questions in the future.
The Pathology Report: The pathology report is important in determining both the treatment plan and prognosis. It is helpful when the breast surgeon, the radiation oncologist, and the medical oncologist can review the slides under the microscope with the pathologist, while simultaneously checking the mammography films with the radiologist. Doctors ask questions, such as: Do the abnormalities on the mammogram appear to correspond with what was removed? Are the margins adequate, or is additional surgery needed, and how will this affect other treatment decisions? No matter how detailed a pathology report is, seeing the actual slides is still better, so ask your doctor if all the specialists involved have had a chance to review your case in this fashion.
The pathology report also contains information on whether the cancer is invasive (infiltrating) or noninvasive (in situ), the type of breast cancer (the vast majority are ductal as opposed to lobular), the grade (low, intermediate, or high), the size, the margin information, and lymph node information. Additional tests may be selected that will reveal features of the cancer that may be important in determining response to treatment. The presence of estrogen and/or progesterone receptors on a tumor means that the tumor growth may be blocked by hormone treatments that interfere with estrogen’s ability to stimulate tumor growth. (It does not imply that estrogen caused the cancer.) Another specific test looks at whether or not the tumor has excess amounts of a protein known as Her-2 neu. This is only found in excess amounts on the surface of about 20 to 30 percent of all breast cancers but is associated with more aggressive cancers.