A new study has reported that sentinel lymph node biopsy is an effective and safe alternative to axillary lymph node dissection for detection of nodal metastases, based on a follow-up period of almost five years. Sentinel lymph node biopsy causes less morbidity (including less lymphedema) and is more cost effective than axillary lymph node dissection. Sentinel lymph node biopsy has replaced axillary lymph node dissection as the preferred procedure for nodal staging. Use of sentinel lymph node biopsy has been reported to have a low false-negative rate, based on short-term follow-up, but there is little data concerning longer-term outcomes. The study was designed to investigate the longer-term outcomes of a consecutive series of breast cancer patients with negative sentinel lymph nodes.

To conduct the study, the authors performed a retrospective review of a database of breast cancer patients at their institution, the H. Lee Moffitt Cancer Center and Research Institute in Tampa, Florida. A total of 1,530 patients with invasive breast cancer had negative sentinel nodes and no axillary node dissection between January 1995 and June 2003. The average invasive tumor size was 1.40 cm. Local recurrences, distant metastases, and survival were determined for these patients during an average follow-up period of 4.92 years. A total of 1,121 (73%) of the patients underwent lumpectomy and 409 (27%) underwent mastectomy.

Four (0.26%) patients experienced local axillary recurrences, 54 (3.53%) had recurrences in the same breast or chest wall as the original tumor, and 24 (1.57%) experienced distant metastases during follow up. The authors conclude that the study data confirms that sentinel lymph node biopsy is an effective and safe alternative to axillary lymph node dissection for detection of nodal metastases in patients with invasive breast cancer and should be used as the standard tool for nodal staging.

Sentinel lymph node biopsies are for staging, not treatment

The primary purpose of lymph node biopsies is to stage breast cancer in order to determine the most appropriate treatment. The number of positive lymph nodes is a useful prognostic indicator. Removing positive lymph nodes with very small metastases appears to have very little, if any, impact on survival. Axillary lymph node dissection used to be performed routinely for almost all breast cancer patients undergoing surgery. This resulted in considerable damage to the tissues surrounding the lymph nodes in a large minority of women, especially those who were overweight. The damage resulted in lymphedema and problems with arm mobility that became permanent in some women. In recent years, if the sentinel lymph node or nodes are negative, axillary lymph node dissection is normally omitted. The present study confirms that this strategy is safe in a community setting (i.e., outside a trial focusing on lymph node surgery).