The aim of this PhD-project was to identify predictors of lymph node metastasis in patients with breast cancer and to integrate these findings in the surgical management of the axilla.

In first phase, we aimed to provide more insight in the biology of lymph node metastasis. We performed gene and miRNA expression profiles of primary tumour tissue and showed that lymph node involvement is not a genetically random process. In a next step, we built a model to predict lymph node involvement based on clinicopathological variables. Tumour size, presence of lymphovascular invasion, multifocality and the location of the tumour in the breast emerged as independent predictors of the lymph node status. Additionally, our data provided evidence that the axillary lymph node status is not only a reflection of the chronological age of a tumour, but also of tumour biology. We then demonstrated that the macrophage density in primary tumour tissue is related to mitotic grade, but not to lymph node status.

In second phase, we aimed to optimise axillary surgery policy in patients with breast cancer. We showed that sentinel lymph node biopsy is at least as accurate as axillary lymph node dissection to detect positive lymph nodes. Additionally, we developed an algorithm for a tailored surgical approach of the axilla. We suggested omitting completion axillary lymph node dissection in a subgroup of patients with a positive lymph node and a low risk of positive non-sentinel lymph nodes. Finally, our findings indicated that implementation of a tailored surgical approach to the axilla results in significant inter-institutional differences.

(BELG J MED ONCOL 2014;8(4):129–31)