Lymphatic Mapping and Sentinel Node Biopsy in the Patient With Breast Cancer

TLDR

The study aims to identify sentinel lymph nodes in invasive breast cancer patients and test whether their histologic features predict those of the remaining axillary nodes. In a prospective trial of 62 patients, intraoperative lymphatic mapping with blue dye and technetium‑labeled sulfur colloid was used to locate and excise the sentinel node, followed by definitive surgery and axillary node dissection to assess metastatic spread. The sentinel node was successfully identified in 92% of cases, was positive in all 18 of 32% of patients with metastases, showed no skip metastases, was the sole site of disease in 67% of metastatic cases, and its involvement strongly predicted axillary nodal status (P < .001), confirming that mapping is feasible and that sentinel node histology reflects the axilla, enabling focused pathology and improved staging accuracy.

Abstract

To identify the sentinel lymph node(s) (SLN[s]) (the first node[s] draining the primary tumor in the regional lymphatic basin) in patients with invasive breast cancer and to test the hypothesis that the histologic characteristics of the SLN predict the histologic characteristics of the remaining lymph nodes in the axilla.A prospective trial.Sixty-two patients with newly diagnosed invasive breast cancers.Patients underwent intraoperative lymphatic mapping using a combination of a vital blue dye and filtered technetium-labeled sulfur colloid. The SLN was identified and removed, followed by a definitive cancer operation, including a complete axillary node dissection.The metastatic distribution in the axilla was determined in patients with occult nodal disease.The SLN was successfully identified in 57 (92%) of 62 patients using the 2 lymphatic mapping procedures. After localization, 18 patients (32%) were found to have metastatic disease, and the SLN tested positive in all 18 patients. There were no "skip" metastases, defined as an SLN that tested negative with higher nodes that tested positive. In 12 (67%) of 18 patients with metastatic disease, the SLN was the only site of disease. The metastatic distribution significantly favored SLN involvement. Among subjects with discordant nodal involvement, the probability of observing the distribution of SLN involvement by chance is very small (P<.001).This study confirms that lymphatic mapping is technically possible in the patient with breast cancer and that the histologic characteristics of the SLN probably reflect the histologic characteristics of the rest of the axillary lymph nodes. The procedure also allows the pathologist to focus the histologic examination on 1 or 2 nodes, potentially increasing the yield of positive dissections and the accuracy of staging.