Axillary Lymph Node Dissection for Breast Cancer May Not Be Necessary
Posted Feb 21 2011 1:55am
AXILLARY LYMPH NODE DISSECTION FOR
BREAST CANCER MAY NOT BE NECESSARY
The management of breast cancer has undergone many advances since the radical mastectomy that first came into popularity in the United States in the late 19 th century. At that time, even early cancers of the breast were managed by surgically removing the entire breast, the underlying chest wall muscles, and all of the lymph nodes under the armpit (axilla). It wasn’t until the 1970s that surgeons began to abandon radical mastectomy, in favor of the less disfiguring modified radical mastectomy, based upon emerging research data at the time. By the 1980s, additional research data had confirmed that women who underwent lumpectomy plus radiation therapy experienced equivalent survival when compared to women who underwent mastectomy. In the late 1990s, another major paradigm shift in the surgical management of breast cancer occurred with the rapid adoption of sentinel lymph node (SLN) biopsy, which had previously also revolutionized the surgical management of melanoma. Following the successful application of SLN biopsy to breast cancer, the 60 to 70 percent of women with breast cancer who have normal axillary SLNs (i.e., no evidence of spread of breast cancer cells to the lymph nodes in the axilla) could now avoid undergoing complete axillary lymph node dissection (ALND), wherein about two-thirds of the armpit lymph nodes are surgically removed. As the risk of arm swelling (lymphedema), numbness, and other long-term side effects associated with ALND are only one-tenth as common following SLN biopsy, the majority of women undergoing breast cancer surgery over the past decade have been able to avoid many of the chronic complications and side effects associated with the more radical surgical approaches used in the past. However, between one-fourth and one-third of women diagnosed with breast cancer will still be found to have tumor cell in their SLNs, and most of these women have routinely been advised to undergo ALND to remove additional armpit lymph nodes.
Now, a newly published clinical research study from the American College of Surgeons Oncology Group has, once again, dramatically shifted the paradigm of breast cancer management. This clinical research study, which I was privileged to participate in when I was a Surgical Oncology Fellow at the John Wayne Cancer Institute, enrolled 891 women newly diagnosed with breast cancer, and with early metastatic cancer involving one or more of their axillary SLNs. These women were evenly randomized into two groups. One group underwent the standard therapy of ALND, while the other half of these patient volunteers were observed, without further surgery, following SLN biopsy. The results of this pioneering breast cancer research study appear in the current issue of the Journal of the American Medical Association.
After an average duration of patient follow-up of more than 6 years, this pivotal clinical study has confirmed what many of us oncologists have long suspected. In women with evidence of microscopic spread of breast cancer to one or more axillary SLNs, there was no difference in overall survival whether or not they went on to undergo ALND, as long as they underwent otherwise standard therapy for lymph-node-positive breast cancer (including lumpectomy, radiation therapy to the breast, and chemotherapy).
I cannot overstate the potential impact of the findings of this important clinical study. However, while some have heralded the findings of this study as breaking important new ground, in fact that ground was broken by the very same pioneering prospective clinical research study (the National Surgical Adjuvant Breast and Bowel Project’s NSABP B-04 study, which began in 1971) that originally led surgeons to abandon radical mastectomy. Within this older large prospective clinical study was an important subgroup of 586 women with palpably enlarged axillary lymph nodes (and which actually indicated a more advanced stage of lymph node involvement than the women who participated in the more modern American College of Surgeons Oncology Group study). Like all of the women who participated in the NSABP B-04 study, these 586 breast cancer patients with enlarged armpit lymph nodes were randomized to undergo radical mastectomy with radical ALND versus mastectomy alone (and no lymph node surgery at all ) combined with radiation therapy. After an average follow-up of 25 years, there was absolutely no difference in survival between the women who underwent radical lymph node surgery combined with radical mastectomy versus those women who underwent simple mastectomy alone (and no lymph node surgery) followed by radiation therapy.
Thus, the newly reported findings of this pivotal American College of Surgeons Oncology Group clinical study only further validates the findings of the nearly 40 year-old NSABP B-04 study, and should put to rest, once and for all, the decades-old debate about the role of surgery in the management of the axillary lymph nodes in patients with newly diagnosed breast cancer. At a minimum, surgeons should now advise their breast cancer patients that there is now 40 years worth of high-level clinical research data showing that the surgical removal of most or all of the armpit lymph nodes (ALND) does not improve survival in women who otherwise undergo standard breast cancer treatment that includes lumpectomy (or mastectomy), chemotherapy, and radiation therapy.
I predict that the findings of these two landmark breast cancer surgical studies will, together, once again revolutionize the surgical management of breast cancer, and will further reduce the adverse impact of surgery on hundreds of thousands of women around the world each year. Indeed, this latest revolution in the management of breast cancer has already started at major cancer centers in the United States, where women are already being advised that the finding of early spread of breast cancer cells to their axillary SLNs no longer mandates “completion ALND,” as long as these patients undergo standard chemotherapy and radiation therapy following lumpectomy and SLN biopsy.
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Dr. Wascher is an oncologic surgeon, professor of surgery, cancer researcher, oncology consultant, and a widely published author