Research remains an essential part of cancer care. In this blog, we will provide information about recent updates or new approvals as it applies to breast cancer written by Dr. Sharon Wilks.
Of the lectures from the 21st Annual International Congress on the Future of Breast Cancer, East, back in July 2022, a wonderful lecture by Dr. Stephanie Wong, who is a breast surgical oncologist with the Jewish General Hospital associated with McGill University Medical School, caught my attention. She did a great lecture on the axillary management in upfront surgery for patients with early breast cancer stages.
In this talk, she reviewed the history of breast cancer surgery management of the axillary node, and it is nice to have a perspective on where we are and how research has impacted care and morbidity in the breast cancer survivor. This review augments the value of research to allow us to move towards more effective and safer forms of surgery.
Before 1970 and probably well in to the late 1970s, radical mastectomy was the recommended treatment for women and men with breast cancer. When considering the radical mastectomy, many remember it is an extensive surgery where the entire breast, all the lymph nodes under the arm of the breast cancer side (ipsilateral) and chest wall muscles are removed.
Extensive lymph node removal was felt to be fundamental to prevention of tumor cells having a chance to spread to the rest of the body. (There were even some surgeons in earlier periods that had added removal of nodes above the collar bone and even brain surgery was done in the 50s to reduce any source of hormone stimulation of breast cancer). Clearly women and men who underwent these radical procedures suffered from the effects of this extensive extraction of tissue with long term deformities and pain that some coined ‘mutilating’ surgery.
In Dr. Wong’s recent talk, she reviewed the NSABP B-04 experience. Here total mastectomy was done but women (1,159 enrolled*) were randomized to the traditional radical mastectomy with extensive lymph node removal (some women had more than 30 nodes removed, unheard of in current time periods) versus a total (modified) mastectomy with postoperative radiation versus total mastectomy alone.
In this study, we learned that patients who appeared to have early stages of breast cancer without obvious nodes involved (not palpable or fixed to the axilla) with extensive surgery had a 40% likelihood of having positive nodes.
In her talk, more contemporary studies done in the late 1990s and early 2000s (the Milan and NSABP 32 studies) confirmed in patients with no obvious clinically involved nodes that about 26-35% will have positive nodes even if clinically appearing to have stage 1 disease.
Sentinel lymph node dissection which involves identification of the first one or 2 nodes that receive material from the breast and removal of that node but leaving other nodes intact became of interest in the late 1990s when those patients with early breast cancer stages were found to have usually only one to two nodes with cancer present.
In the NSABP B32 study (enrolled patients between 1999-2004 with 5,611 patients enrolled), it was proven that this less extensive surgery was able to identify nodes that were sentinel in greater than 90% of the cases. Only 26% of the total group have nodes positive (these patients were very early stage with favorable tumor types) and of those 26% with a positive SLN, the majority (61.4%) had only 1 positive node.
Now we have studies that show if a person has undergone breast conserving surgery (one important study that more recently was completed is the ACOSOG Z0011 that enrolled 856 patients with positive sentinel lymph nodes) that are found to have 2 or less positive lymph nodes (microscopic), there is no value in removing additional nodes. Most will undergo radiation to the breast who undergo breast conserving surgery (lumpectomy) and receive postoperative radiation to the level 1 axillary nodes.
Long term follow-up evaluating axillary recurrences and overall survival have seen no significant impact on survival or axillary recurrences.
In Dr. Wong’s talk, she reviewed outcomes of several studies including IBCSG 23-01, AATRM, Z0011, AMAROS, OTOASAR and SINODARS studies (the total number of patients in these studies total in the thousands with several year, most have more than five years, of follow-up) that showed rates of 1-2% axillary recurrences in those patients in patients that underwent conservative surgery and less extensive lymph node removal.
Lymph node removal is a known risk factor for lymphedema, long term arm and chest wall pain and the likelihood of these changes is greater with more extensive lymph node removal. Thanks to research we have improved ways to deescalate lymph node removal without compromising survival rates. (In the early NSABP B4, there was no established role for systemic chemotherapy and long-term survival rates were not worsened with surgery and less lymph node removal alone even amongst patients who were found to have positive lymph node involvement).
Clearly survival rates are improving, and one current focus of research today is to avoid long term side effects of treatment amongst patients who have favorable prognosis by ‘de-escalating’ methods of surgery, radiation, and chemotherapy.
Please remember that participating in research trials can make a difference. Clinical trials often ensure at least as good of an outcome in cancer control as currently accepted measures but without research, we cannot move forward and improve outcomes in cancer care. I think about those 1,159 patients back in the 1970s. It is hard to believe that this many women volunteered to be randomly assigned to these novel approaches, and in my opinion, it is a credit to these angels and surgeons who bravely moved forward with the scientific principles of lesser axillary surgery. The information that we have learned from those brave individuals has helped us prove time and time again that less sometimes can be more. We must continue to move forward bravely to fight cancer in better and safer ways.