Preceding sentinel node biopsy in early breast cancer: does it affect the number of axillary lymph nodes?

In the staging of early breast cancer a positive sentinel node biopsy is followed by axillary dissection in order to assess the number of metastasised lymph nodes. Immediate axillary dissection has been abandoned in our centre. If necessary, an axillary dissection takes place about two weeks later, but the post surgical inflammatory reaction might hinder dissection and decrease the number of removed lymph nodes. In a retrospective study, the total number of lymph nodes removed by sentinel node biopsy followed later by axillary dissection (n = 53) was compared with the total number of lymph nodes removed by axillary dissection without previous sentinel node biopsy in combination with breast conserving therapy (n = 113), or following breast conserving therapy (n = 15), or in combination with mastectomy (n = 65). A total number of 12 (median) lymph nodes were removed by sentinel node biopsy followed later by axillary dissection. Only in the mastectomy + axillary dissection group were less lymph nodes (median of 9) removed (P = 0.009). Multiple regression showed the total number of axillary lymph nodes to be correlated with age (R = -0.21; P = 0.002) and with the number of lymph nodes with metastasis (R = 0.31; P < 0.0001). Age distribution showed that the mastectomy + axillary dissection group had the oldest patient population. The number of removed axillary lymph nodes is not decreased by preceding sentinel node biopsy, but depends on other factors.