9 January 2017
The American Society of Clinical Oncology recently updated their guideline on sentinel node biopsy for patients with early stage breast cancer. Axillary dissection, or removal of underarm lymph nodes, has traditionally accompanied mastectomy and lumpectomy surgery. It was initially felt that removal of these nodes was important to prevent the cancer from spreading to other areas in the body. However, the more modern view is that the nodal status provides prognostic information only. If the tumor has spread into the lymph nodes, we know that surgery is not enough, and chemotherapy is usually recommended, in order to treat cancer cells that have spread outside the breast.
Recognizing that most early-stage breast cancer patients did not have spread to their nodes, the sentinel node mapping technique was developed. Initially described for melanoma, the procedure involves injection of a radioactive material and/or blue dye into the breast. The injected material is then absorbed by the lymphatic vessels in the breast, to “light the path” to the first nodes in the underarm. Studies performed in the 1980s demonstrated that if these nodes were “negative” (no cancer cells), the likelihood of cancer cells in other lymph nodes in the underarm was less than 1-2%, Patients undergoing the less invasive procedure had no higher rates of cancer recurrence, and by the early 1990s, sentinel node biopsy became standard of care for patients undergoing lumpectomy or mastectomy. However, Dr. Elaine Schattner, writing in Forbes, notes that unfortunately many women still undergo the more extensive axillary dissection. More aggressive surgery only leads to higher rates of complications, which can include pain, arm numbness, limitation in movement, and lymphedema – permanent arm swelling. She recommends (as do I) that women question their doctors if more extensive surgery is recommended.
The next breakthrough in axillary surgery came when Dr. Armando Giuliano and colleagues showed that even when cancer had spread to 1-2 underarm lymph nodes, removal of additional nodes did not result in better outcomes. The patients studied all underwent lumpectomy and they all received postoperative chemotherapy (due to spread to the lymph nodes) and radiation therapy (standard after lumpectomy). It is important to note is that this landmark “Z11” study was performed in lumpectomy patients. In those undergoing mastectomy, it is still recommended to perform an axillary dissection if the sentinel node is “positive” (has cancer cells). Studies are ongoing to evaluate the role for less extensive axillary node surgery in mastectomy patients.
Do we still need axillary staging? In their Choosing Wisely statement, the Society of Surgical Oncology recommends that surgeons should not routinely perform axillary surgery in patients over the age of 70. In a separate paper, Dr. Judy Boughey and colleagues note that approximately 15% of women over the age of 70 will have positive nodes. She noted that tumor biology, size and grade are important factors to consider in addition to patient age, and the status of the axillary nodes still provides important information in many patients. However, she stressed that “reevaluating and questioning our daily practice is important to ensure that we are continually doing the best for our patients. Just doing something because we can or because we have always done it is not reason enough to continue doing it.” I couldn’t agree more.