Occult axillary lymph node metastases are of no prognostic significance in breast cancer

Abstract

The significance of occult metastases in axillary lymph nodes in patients with carcinoma of the breast is controversial. Additional sections were cut from the axillary lymph nodes of 477 women with invasive carcinoma of the breast, in whom no metastases were seen on initial assessment of haematoxylin and eosin stained sections of the nodes. One section was stained with haematoxylin and eosin, and one using immunohistochemistry with two anti-epithelial antibodies (CAM5.2 and HMFG2). Occult metastases were found in 60 patients (13%). The median follow-up was 18.9 years with 153 breast cancer related deaths. There was no difference in survival between those with and those without occult metastases. Multivariate analysis, however, showed that survival was related to tumour size and histological grade. This node-negative group was compared with a second group of 202 patients who had one involved axillary node found on initial assessment of the haematoxylin and eosin sections; survival was worse in the patients in whom a nodal metastasis was found at the time of surgery. Survival was not related to the size of nodal metastases in the occult metastases and single node positive groups. Some previous studies have found a worse prognosis associated with occult metastases on univariate analysis, but the evidence that it is an independent prognostic factor on multivariate analysis is weak. We believe that the current evidence does not support the routine use of serial sections or immunohistochemistry for the detection of occult metastases in the management of lymph node negative patients, but that the traditional factors of histological grade and tumour size are useful.

Figure 1

Overall survival of axillary node negative patients with and without occult metastases, and of patients with a single involved axillary node. There was no difference between node negative patients with and without occult metastases χ²=1.9, P=0.17. Survival was worse in patients with a single involved axillary node compared with the node negative group χ²=32.7, P<0.0001, and compared with the node negative patients with occult metastases χ²=4.1, P=0.04. The table underneath shows patients at risk at 5-yearly intervals.

Figure 2

Overall survival is not related to the size of the largest axillary nodal metastasis in patients with occult metastasis or single node positive, χ²=0.52, P=0.91. Metastasis size was divided using cut-offs of 0.2, 2 and 10 mm.