Is it necessary to remove cancerous lymph nodes in breast cancer patients?

Breast cancer specialists have long known that for many women with early-stage breast cancer, breast conservation (surgery + postoperative radiation therapy; RT) has the same survival benefit for women as mastectomy (complete removal of the breast). However, the other component of breast cancer surgery involves removing lymph nodes under the arm. For decades, many breast cancer surgeons have felt strongly that removal of any and all cancerous lymph nodes under the arm was a requirement in order to give their patients’ the best chance at survival. According to the results of a major randomized controlled trial (RCT), it appears that these surgical experts have been wrong.

In the Journal of the American Medical Association (JAMA), lead author Dr. Giuliano and colleagues from the John Wayne Cancer Institute in California reported the American College of Surgical Oncology Group (ACoSOG) Z11 trial. In this large RCT, all women with early stage breast cancer underwent surgical removal of their breast tumor by lumpectomy and sentinel lymph node (SLN) biopsy.

Women who were found to have cancer cells in 1 or 2 cancerous SLN’s in the Z11 trial were then randomized between no further surgery under the arm (half of the patients) versus full axillary lymph node dissection (ALND; the other half of the patients). The results of this trial involving 900 women confirmed that there was no improvement in survival for women who had these lymph nodes removed by ALND. An important point to note is that all of these patients received whole breast RT, which usually includes treatment of lymph nodes under the arm that are most at risk for cancer.

The results are no surprise to most experts in breast radiation oncology. It’s long been known that RT kills microscopic breast cancer cells quite well. The Z11 trial should put to rest any concerns on the part of less progressive breast surgeons. While evaluation of lymph nodes may be prognostic (predictive of outcome) and important to determine which treatment is best after surgery, it’s very rarely therapeutic for patients with early stage breast cancer. There’s no clear benefit to ALND in terms of cancer control for most of these women. A limited lymph node evaluation should be performed via SLN biopsy for most patients. The bottom line is a clear benefit for women due to less potential harm. Less axillary surgery means a lower risk of permanent arm swelling, as well as other potentially life-altering complications.