Axillary node metastasis from T1NOMO breast cancer: Possible avoidance of dissection in a subgroup

Background: Axillary lymph node dissection is now no longer considered to be the standard treatment in all patients with invasive breast cancer. We have attempted to identify a sub-group of patients with invasive breast carcinoma who may not need to undergo axillary lymph node dissection. Methods: Patients (n = 823) with T1N0M0 invasive breast cancer treated at our hospital between 1970 and 1994 were studied. We investigated the relationship between positive axillary lymph nodes and the following clinico-pathological factors: patient age, menopausal status, contralateral breast cancer (synchronous or asynchronous), tumor location, tumor size (T: cm), histopathology, histological grade, presence or absence of malignant microcalcification or spiculation on mammography and estrogen receptor status. Results: The incidence of axillary lymph node metastases in patients with T1N0M0 invasive breast cancer was 25% (208/823). The node-negative group was significantly older than the node-positive group. Premenopausal patients had a higher rate of lymph node metastases although this was not significant. The frequency of nodal metastases when related to the tumor size was as follows: T less than or equal to 1.0 cm, 17%, T less than or equal to 1.5 cm, 25%; T less than or equal to 2.0 cm, 29%. Mammography revealed that patients with malignant calcification or spiculation had a significantly higher rate of nodal metastases than those without these findings. Certain tumor types (medullary, mucinous and tubular carcinomas) had lower positive rates for lymph node involvement. With regard to the histological grade, lymph node positivity increased significantly with high-grade tumors. No correlation was observed between any other factors and the presence or absence of lymph node metastases. Conclusions: It may be possible to avoid axillary lymph node dissection in postmenopausal patients (50 years or older) where the histological type is favorable when the tumor diameter is less than or equal to 1.0 cm and when microcalcification or spiculation is absent on mammography.