ABSTRACT
<p><b>OBJECTIVE</b>To analyze the characteristics of lymph node metastasis and prognosis in patients with T1 breast cancer.</p><p><b>METHODS</b>The clinicopathological data of 354 patients with T1 breast cancer after standard treatment from March 2007 to September 2011 were collected to analyze the relationship between the clinical characteristics of T1 breast cancer, lymph node metastasis and prognostic features.</p><p><b>RESULTS</b>In the 354 patients with T1 breast cancer, 105 patients (29.7%) had lymph node metastasis, among them 73 cases (69.5%) had 1-3 lymph node metastasis, and 32 cases (30.5%) had more than 4 lymph node metastasis. The lymph node metastasis rate was 8.3% in T1a patients, 39.7% in T1b patients, and 30.4% in T1c cases (P = 0.005). Pairwise comparison showed that the difference of lymph node metastasis rate between T1a, T1b and T1c patients was statistically significant (P = 0.001 and P = 0.006, respectively). The difference of lymph node metastasis rates in T1b and T1c patients was statistically insignificant (P = 0.171). In the 354 patients of T1 breast cancer, 92 patients had vascular tumor thrombi and their lymph node metastasis rate was 71.7%, while the lymph node metastasis rate in 262 patients without vascular tumor thrombus was 14.9% (P < 0.001). The median follow-up was 49 months (range 27-81 months). 12 patients developed recurrence, and 3 patients died, one of them died of cerebrovascular accident. The 4-year disease-free survival for all patients was 96.6%, and the 4-year overall survival rate was 99.2%.</p><p><b>CONCLUSIONS</b>There is a correlation between vascular tumor thrombus, tumor size and lymph node metastasis rate. The lymph node metastasis rate is lower in T1a patients and relatively higher in T1b/c patients. Compared with patients without vascular tumor thrombus, the T1 breast cancer patients with vascular tumor thrombi have a higher lymph node metastasis rate. Generally speaking, there is a still good prognosis in patients with T1 breast cancer.</p>