T1a and T1b breast cancer: a twelve-year experience

To understand the prevalence of axillary node metastasis and survival of patients with T1a and T1b breast cancers, we reviewed the experience at a large community hospital. All patients in the William Beaumont Hospital tumor registry with breast cancer treated between January 1983 and November 1995 were evaluated for tumor size, age, cell type, and the presence or absence of axillary node disease. Long-term survival was evaluated in patients treated between 1983 and 1992. The patients were defined as premenopausal or postmenopausal based on age (49 years or less, premenopausal; 50 years or greater, postmenopausal). Of the 4590 patients treated for breast cancer from 1983 to 1995, 915 had tumors 1.0 cm or less in size. Of 181 patients who had T1a cancer, 27 were premenopausal, and 154 were postmenopausal. Twenty-three premenopausal patients had axillary lymph nodes examined, two (8.7%) had histologically positive lymph nodes. Of 118 postmenopausal patients who had axillary nodes examined, six (5.1%) had positive lymph nodes. In those with T1b tumors, 130 patients were premenopausal; 604 patients were postmenopausal. Of these, 119 premenopausal patients had axillary nodes examined, and 29 (24.4%) had positive lymph nodes. Of 464 postmenopausal patients who had axillary nodes examined, 66 (14.2%) had positive nodes. The overall, disease-free, and tumor-specific survival rates for patients with T1a tumors were 93.8, 87.5, and 93.8 per cent (premenopausal) and 86.2, 95.4, and 95.4 per cent (postmenopausal), respectively. These survival rates for patients with T1b tumors were 87.8, 87.8, and 91.1 per cent (premenopausal) and 82.9, 88.5, and 92.9 per cent (postmenopausal), respectively. Premenopausal T1b patients had a higher rate of nodal involvement than postmenopausal T1b patients (P = 0.011). Postmenopausal T1b patients had a higher nodal metastasis rate than postmenopausal T1a patients (P = 0.01). T1b patients had a higher rate of axillary involvement than did T1a patients (P = 0.0018). Based on the rate of axillary lymph node metastasis and survival statistics, there may be a role for axillary node dissection in select patients with tumors less than 1.0 cm. in size.