Additional Lymph Node Removal May Not Improve Survival in Breast Cancer Patients with Small Amounts of Cancer in Sentinel Node

Among women with early-stage breast cancer and small amounts of cancer (micrometastases) in the sentinel lymph node, removal of additional lymph nodes (completion axillary lymph node dissection) does not appear to improve overall survival. The results of this study were presented at the 2010 annual meeting of the American Society of Clinical Oncology.

For women with early breast cancer, determining whether the cancer has spread to the axillary (under the arm) lymph nodes is an important part of cancer staging. Evaluation of the axillary nodes may involve either an axillary lymph node dissection (ALND), in which many lymph nodes are surgically removed and evaluated or a less extensive procedure known as a sentinel lymph node biopsy.

The sentinel nodes are the first lymph nodes to which cancer is likely to spread. If the sentinel nodes are free of cancer, no further lymph node evaluation is performed. If the sentinel nodes contain cancer, however, most women then undergo ALND to remove additional nodes. This additional lymph node surgery has been shown to help control cancer locally, but the effect on survival has been controversial. Establishing the benefits of completion ALND is important because it can cause significant side effects such as pain, discomfort, and swelling (lymphedema).

To evaluate the effects of ALND in breast cancer patients with micrometastases in the sentinel node, researchers conducted a Phase III study among 991 women. Half the women underwent completion ALND, and half did not.

Five-year overall survival was 91.9% among women who underwent ALND and 92.5% among women who did not undergo ALND.Disease-free survival was 82.2% among women who underwent ALND and 83.8% among women who did not undergo ALND.The rate of local/regional recurrence (recurrence in or near the breast) was 4.3% among women who underwent ALND and 3.4% among women who did not undergo ALND.

In a prepared statement, the lead author of the study explained, “Our findings suggest that there may not be a benefit to removing more lymph nodes than the sentinel node only, and that women can avoid the risk of additional side effects that come with more extensive lymph node removal. Axillary lymph node dissection will still be needed in some cases, but these findings show it may be necessary for far fewer women.”

Reference: Giuliano AE, McCall LM, Beitsch PD et al. ACOSOG Z0011: A randomized trial of axillary node dissection in women with clinical T1-2 N0 M0 breast cancer who have a positive sentinel node. Presented at the 2010 annual meeting of the American Society of Clinical Oncology. June 4-8, 2010. Chicago, IL. Abstract CRA 506.

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Study Evaluates Impact of Lymph Node Removal in Early-stage Breast Cancer

Early-stage breast cancer patients without evidence of cancer in their sentinel lymph node who did not have additional lymph nodes removed report fewer side effects to the arm and breast than patients who undergo additional lymph node removal. These findings were recently published in the Journal of Clinical Oncology.[1]

For women with early breast cancer, determining whether the cancer has spread to the axillary (under the arm) lymph nodes is an important part of cancer staging. Evaluation of the axillary nodes may involve either an axillary lymph node dissection (ALND), in which many lymph nodes are surgically removed and evaluated, or a less extensive procedure known as a sentinel lymph node biopsy.

The sentinel nodes are the first lymph nodes to which cancer is likely to spread. A sentinel lymph node biopsy involves the removal of only these nodes. If cancer is found in the sentinel nodes, most women undergo additional lymph node removal. If the sentinel nodes are free of cancer, however, women may not require any additional lymph node removal. Avoidance of extensive lymph node removal reduces the risk of side effects such as lymphedema (swelling).

Several studies have been conducted to determine the efficacy of sentinel lymph node biopsy versus more extensive lymph node surgery. In a recent study presented at the 2010 annual meeting of the American Society of Clinical Oncology, researchers reported that among women with early breast cancer and no evidence of cancer in the sentinel lymph nodes, sentinel lymph node biopsy alone is as effective as more extensive lymph node surgery.[2] In addition to efficacy data, researchers are interested in quantifying how these procedures impact a patient’s quality of life both immediately following surgery as well as months and years later.

In the current substudy of a Phase III trial, researchers evaluated patient-reported data to determine the impact of sentinel node biopsy alone versus sentinel node biopsy plus ALND. The 749 patients in this study had operable, early-stage breast cancer with no clinical evidence of cancer in the lymph nodes. In addition, the patients in this substudy did not have evidence of cancer in the sentinel lymph node. Three-hundred fifty-six had been randomized to undergo sentinel lymph node biopsy plus ALND, and 391 underwent sentinel lymph node biopsy alone. Patients completed a questionnaire before surgery, immediately after surgery, and every six months for approximately three years to assess quality of life, breast symptoms, as well as arm function and symptoms.

During the postoperative period, sentinel node biopsy plus ALND was associated with an elevated likelihood of arm and/or breast symptoms, worse quality of life, and more limitations in work and social activity compared with sentinel node biopsy alone.In as little as a year after the procedure, a relatively small percentage of patients in either group reported moderate or severe side effects.?

The researchers concluded that among patients with no evidence of cancer in their sentinel nodes, sentinel node biopsy alone was associated with fewer arm and breast side effects and better quality of life. Over time, however, some of the differences between the groups diminished.?

Reference:

[1] Land SR, Kopec JA, Julian TB, et al. Patient-reported outcomes in sentinel-node negative adjuvant breast cancer patients receiving sentinel-node biopsy or axillary dissection: National Surgical Adjuvant Breast and Bowel Project Phase III Protocol B-32. Journal of Clinical Oncology. [early online publication]. August 2, 2010.

[2] Krag DN, Anderson SJ, Julian TB et al. Primary outcome results of NSABP B-32, a randomized phase III clinical trial to compare sentinel node resection (SNR) to conventional axillary dissection (AD) in clinically node-negative breast cancer patients. Presented at the 2010 annual meeting of the American Society of Clinical Oncology. June 4-8, 2010. Chicago, IL. Abstract LBA 505.

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Hidden Lymph Node Metastases Have Small Effect on Breast Cancer Outcomes

Among women with early breast cancer and a sentinel lymph node that appears to be cancer-free on routine evaluation, more extensive lymph node evaluation identifies small areas of cancer in approximately 16% of women. These small, hidden areas of cancer appear to have only a small effect on cancer outcomes, suggesting that current approaches to lymph node evaluation are adequate. These results were published in the New England Journal of Medicine.

For women with early breast cancer, determining whether the cancer has spread to the axillary (under the arm) lymph nodes is an important part of cancer staging. Evaluation of the axillary nodes may involve either an axillary lymph node dissection (ALND), in which many lymph nodes are surgically removed and evaluated, or a less extensive procedure known as a sentinel lymph node biopsy.

Sometimes, very small areas of cancer may be missed on routine lymph node evaluation. These areas of cancer are referred to as “occult” (hidden) metastases. Some previous studies have found that breast cancer patients with occult lymph node metastases have worse outcomes than patients with lymph nodes that are truly cancer-free.

To further evaluate the importance of occult lymph node metastases, researchers evaluated information from the NSABP-B32 study. The primary objective of the study was to evaluate the safety and effectiveness of sentinel lymph node biopsy, but researchers have also been able to explore other questions, including the impact of occult metastases.

The current analysis focused on 3,887 women with sentinel lymph nodes that were negative (cancer-free) on routine evaluation. These lymph nodes underwent further evaluation in an effort to detect occult metastases.

Occult metastases were detected in 16% of patients.The presence of occult metastases was linked with a higher rate of recurrence and worse survival, but these effects were small. Five-year overall survival, for example, was 94.6% among women with occult metastases and 95.8% among women without occult metastases.

The researchers conclude that although occult metastases appear to influence breast cancer outcomes, the magnitude of the effect is very small. Efforts to detect occult metastases appear unlikely to provide much benefit. The researchers note that continued follow-up is warranted, and it remains possible that these results will change as more information becomes available. ?

Reference: Weaver DL, Ashikaga T, Krag KN et al. Effect of occult metastases on survival in node-negative breast cancer. New England Journal of Medicine. Early online publication January 19, 2011.

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