Incomplete axillary dissection in early breast-cancer and the risk of erroneous staging.

Maximum control of local disease in early breast cancer is obtained by breast conserving surgery, minimally invasive surgery of the axilla and consecutive selection for adjuvant therapy based on the number of involved axillary level I nodes. The answer to the question what is a 'node negative' patient? by defining the number of lymph nodes excised at operation exclusively, and the number of involved nodes found by the pathologist is given. Based on the data of Veronesi et al (Eur J Surg Oncol 16: 127-133, 1990) on 1446 complete axillary dissections performed between 1983-1986, the mathematical basis of the incomplete axillary dissection of the axilla in early breast cancer is presented: (i) To achieve a degree of confidence of 90% of the entire axilla being negative, histological examination of 10 level I nodes for a T1 tumor and 11 level I nodes for a T2 primary are necessary. In order to obtain these lymph nodes a total en bloc dissection of level I is indicated. (ii) The axillary status was considered negative if 10 or more lymph nodes for T1 or 11 or more in T2 tumors were found and were negative. (iii) The axillary status was considered positive, if <10 lymph nodes in T1 or <11 nodes in T2 tumors were found, even if they all were negative. If positive lymph nodes are left or estimated in the axilla after incomplete dissection, surgical treatment of the axilla is mandatory.