Profile of immune cells in axillary lymph nodes predicts disease-free survival in breast cancer

Breast cancer often spreads through the lymph nodes in the arm pits (so-called axillary lymph nodes), and whether these lymph nodes are tumor-free or contain small metastases is an important factor in the decision of how aggressively to treat a patient.

Peter Lee and colleagues (from Stanford University) now report in the open access journal PLoS Medicine that looking at the immune status of lymph nodes might teach us even more about a specific breast tumor. They found that the 'immune profile' (i.e. the number and composition of immune cells) of an axillary lymph node can independently predict the chances that the cancer will come back. This suggests that lymph node immune profiles can help to inform individualized treatment decisions.

The researchers examined 104 axillary lymph nodes from 77 patients. Five-year follow-up data were available for all patients, 33 of whom had disease recurrence within that time. They found that, regardless of whether the nodes contained tumor cells, the numbers of two different sets of immune cells, CD4 T cells and dendritic cells, were correlated with disease-free survival. Moreover, for this group of patients, the predictive power of the immune profiles was better than that of any other clinical parameters, including tumor size and extent or size of lymph node metastases.

All patients in this study had some lymph nodes that contained tumor cells, and the results suggest that for such patients, immune profile data from axillary nodes hold additional information on the probability of disease recurrence. An important open question is whether immune profile information from lymph nodes can predict risk of recurrence even in women whose cancers are caught at a very early stage where they have not yet spread to any lymph nodes.