Axillary lymph node dissection in non-palpable breast cancers.

The study concerns 265 patients with axillary lymph node dissection for non-palpable breast cancer. The mammographically detected breast tumors were: 36 ductal carcinomas in situ (DCIS), 23 microinvasive carcinomas, 206 invasive carcinomas of which 179 were invasive ductal cancers (IDC), 25 invasive lobular cancers (ILC) and 2 mucinous invasive carcinomas. The histologic size of the invasive component was less than or equal to 5 mm in 38 cases, 6-10 mm in 84 cases, 11-15 mm in 53 cases, 16-20 mm in 16 cases, > 20 mm in 15 cases, Axillary dissection was performed immediately during the initial surgical procedure in 209 patients (79%) or secondarily in 56 (21%) according to the results of intraoperative examination of surgical specimens on frozen sections. Axillary lymph node involvement was not found in DCIS, microinvasive carcinomas or invasive carcinomas less than or equal to 5 mm in size. Among all 206 invasive breast carcinomas, lymph node involvement was found in 7.8% (16/206) of cases. There were 9/84 (10.7%) in tumors > 10 mm, 7/122 (5.8%) in tumors less than or equal to 10 mm. Thus, it is concluded that lymph node involvement is unlikely to be found in patients with non palpable breast cancers, specially those with carcinoma in situ, microinvasive breast tumors and invasive breast cancer with less than 5 mm maximum diameter size. Axillary dissection may be avoided in these patients. However, the use of new prognostic factors of lymph node involvement may help in the definition of patient group.