Many women with early-stage, invasive breast cancer can safely forego surgery to remove most of the lymph nodes in the armpit even when a small number of those nodes contain cancer, a landmark study shows.
The Z0011 clinical trial found no significant differences in overall survival or regional recurrence risk among those who underwent sentinel lymph node dissection rather than axillary lymph node dissection, a more invasive surgery with a higher risk of side effects.
Study participants had invasive breast cancers of 5 centimeters or less and at least one but not more than three sentinel nodes that tested positive for cancer. They all received treatment with chemotherapy or hormonal therapy after breast surgery. Under current treatment guidelines, these women would have surgery to remove more axillary lymph nodes. Z0011 researchers concluded that the guidelines should be changed to allow such women to receive the less invasive surgery.
Background of the Clinical Trial
The treatment of cancerous nodes is based on research conducted before the 1980s that proved axillary lymph node dissection, surgery to remove most lymph nodes in the armpit, lessens the chances of regional recurrence. Although effective, ALND carries a high risk of side effects, including swelling, infection and lymphedema.
Doctors later developed sentinel lymph node dissection surgery, which removes only the first lymph nodes in the armpit where cancer is likely to travel. SLND has fewer side effects than axillary dissection but gives the same information about whether cancer is in the nodes. Today, standard surgical treatment begins with sentinel node dissection. Women who have cancer in the nodes then receive a full axillary surgery.
Goals of the Clinical Trial
No clinical trial has directly asked whether removing more lymph nodes improves survival. In the years since sentinel lymph node dissection was introduced, targeted treatments have become the standard in cancer care, possibly eliminating the need for additional lymph node removal. Most important, today we know treatment outcomes are based as much on genetic traits of the cancer as on the number of cancerous lymph nodes.
The Z0011 researchers studied the role of axillary dissection in prolonging overall survival among women with several cancerous lymph nodes who received modern cancer care. Overall survival is the time lived from entry into the study until death from any cause. They also looked at side effects of the surgeries and disease-free survival, or how long from the start of the study participants went without a recurrence of breast cancer.
Structure of the Trial
Between 1999 and 2004, more than 800 women nationwide enrolled in this phase III study. All participants had lumpectomy that removed a tumor of up to 5 centimeters across and sentinel dissection that found up to three cancerous sentinel lymph nodes.
Participants were then randomly assigned to receive either a full axillary node dissection (the standard treatment) or no further surgery (the treatment under study). Most had standard whole-breast radiation therapy, which typically reaches the lymph nodes. The women also received chemotherapy, targeted therapy or hormonal therapy, based on the traits of the cancer.
After an average of 6.3 years, the two groups had very similar overall survival: 92.5 percent in the sentinel group, versus 91.8 percent in the axillary group. This result held regardless of type of breast cancer, which suggests SLND works as well as axillary dissection at lengthening life.
The groups also did not differ significantly in disease-free survival. After five years, 83.9 percent of the sentinel node group went without a recurrence, versus 82.2 percent of the ALND group.
About 70 percent of participants in the axillary lymph node group had side effects such as shoulder pain, weakness, infection and tingling, versus 25 percent in the sentinel group. Cases of lymphedema were significantly higher in the axillary group.
What These Findings Mean For You
If a tumor is 5 centimeters or less across and you have fewer than four cancerous sentinel nodes, this study strongly suggests that you can safely avoid axillary node dissection and its potential side effects. Z0011 showed that taking out more lymph nodes increases your risk for side effects without lengthening life.
These findings are limited to women who can have lumpectomy, whole-breast radiation and post-surgical, or adjuvant, treatment. They do not include women have mastectomy, do not get radiation after lumpectomy or receive it lying flat (prone), and undergo neoadjuvant therapy or partial-breast irradiation.
The study authors encourage a change to the treatment guidelines, but it may take time for doctors to accept these findings as common practice. If your diagnosis is similar to those of participants in this study, speak with your doctors about Z0011. Ask, “Why is axillary lymph node dissection right for me? What are the risks and benefits?” For more tips on talking with your doctor, visit our section on Lymph Node Biopsy.
A Giuliano, K Hunt, K Ballman, P Beitsch, P Whitworth, et al. Axillary Dissection vs No Axillary Dissection in Women with Invasive Breast Cancer and Sentinel Node Metastasis: A Randomized Clinical Trial. JAMA. 2011;305(6):569-575.