Objective: To investigate the hypothesis that lymphatic metastasis of breast cancer progresses in a sequential fashion, and whether the first lymph node on a direct drainage pathway (first-echelon node, sentinel node) can be identified in a mastectomy specimen.
Design: Descriptive analysis.
Setting: The Netherlands Cancer Institute (Antoni van Leeuwenhoek Hospital), Amsterdam, the Netherlands.
Methods: In 22 patients with clinically localized breast cancer and five with breast cancer and axillary lymphadenopathy, patent blue dye was administered preoperatively into the primary tumor. After mastectomy and axillary lymph node dissection, blue stained lymphatic channels were dissected down to the first draining lymph nodes. These sentinel nodes were removed from the specimen and examined separately for presence of metastatic disease.
Results: In 2/5 patients with palpable axillary metastases and in one patient with a tumour in the medial upper quadrant, no sentinel node was found. A total of 35 first-echelon nodes was identified in the 22 patients without palpable lymphadenopathy, on average 1.6 nodes per patient (range: 1-4). In 10 of these patients, metastatic tumour was found in the sentinel nodes. In 6 of these 10 patients, no metastatic disease was detected in the remaining axillary nodes. Metastasis was never found in the other axillary nodes if the sentinel node was disease-free.
Conclusions: Dissemination of breast cancer to the axillary nodes appears to occur in a sequential fashion. Patent blue dye drains from the tumour in the breast to the axillary lymph nodes in mammary cancer patients. These blue nodes can be identified in the surgical specimen.