Patients with breast cancer who need surgical staging of their lymph nodes now have an alternative to extensive surgical removal (axillary dissection) of lymph nodes. Preliminary studies now suggest that accurate staging of the status of a patient’s lymph nodes can be achieved by removing one or two of the first lymph nodes (sentinel nodes) receiving drainage from the breast rather than a more extensive surgery that removes at least 15 nodes.
Removal of the sentinel nodes only is desirable since more risks and discomfort are associated with the more extensive axillary dissection surgery. These include: a larger incision, longer recovery period, the need for a surgical drain and lymphedema (chronic swelling in the arm). These problems are reduced by the sentinel node procedure because of the smaller incision and reduced amount of tissue removed from the body. In addition to these benefits, the sentinel nodes themselves may be examined in even greater detail by the pathologist for micrometastases.
The Dean/St. Mary’s Experience
As part of an effort for comprehensive, multi-disciplinary front line breast diagnosis and treatment, sentinel node mapping has been offered at St. Mary’s Hospital in conjunction with Madison Radiologists, the Department of Pathology and the Dean Clinic Department of General Surgery since 1999.
In order to achieve the equivalent staging information as the more extensive axillary node resection, the procedure should be performed after adequate experience has been gained by the surgeon. The surgeons at Dean Clinic in Madison have undergone internal quality control to insure this by correlating the staging results of their sentinel node procedures with more extensive axillary dissections on the same patients. With the accuracy of their surgical technique now confirmed, staging sentinel node procedures performed at St. Mary’s Hospital can be offered as an option to more extensive axillary node dissection in many circumstances.
Sentinel node mapping with radionuclide may be performed in conjunction with blue dye injection by the surgeon prior to incision. Some studies have shown improved accuracy when both blue dye and radionuclide are used together. Decision on the agents used for the sentinel node mapping depends on the preference of the surgeon.
The initial nuclear radiology sentinel node mapping is performed by our radiologists. We inject a small amount of radioactive material (radionuclide) into the breast near a biopsy proven tumor to assist the surgeon in localizing the lymph node or nodes receiving lymphatic fluid from the vicinity of the tumor. This typically requires four small injections into the skin of the breast. Imaging is then usually performed using a special camera (gamma camera) which is sensitive to the radionuclide. The skin over the node or nodes is then marked for surgery (see figure). The procedure generally takes one to two hours to complete in the Department of Nuclear Medicine and is usually done on the day of surgery just prior to lumpectomy or mastectomy. Then, in the operating room, surgeons use a hand held radiation detector to further zero in on the appropriate node for removal. These nodes can then be examined in detail by the pathologist, allowing accurate staging of the cancer.
Additional information can be obtained at: