Background: Microvessel density (MVD) is a measure of the extent of new blood vessel growth or angiogenesis, which is required for tumor progression. Increased MVD in primary breast cancers appears to adversely affect disease-free survival and overall survival in patients with breast cancer. However, the clinical implications of angiogenesis in breast cancer metastases have not been well studied. The purpose of this study was to compare intratumoral MVD in primary breast cancer tissues with MVD in axillary lymph node metastases and to evaluate the relationships among primary- and metastatic-tumor MVD, disease-free survival, and overall survival in patients with lymph node-positive, stage II breast cancer who were treated with adjuvant chemotherapy in Cancer and Leukemia Group B Protocol 8082.
Methods: Immunostaining for factor VIII-related antigen was performed on tissue sections from 47 primary tumors and 91 axillary lymph nodes containing metastases from 110 patients with lymph node-positive breast cancer. Sections were examined for the presence or absence of focal areas of relatively intense neovascularization (vascular hot spots), and a quantitative assessment of intratumoral MVD was performed.
Results: The presence of vascular hot spots in axillary lymph node metastases, but not primary breast cancers, was associated with statistically significantly decreased disease-free survival (P =.006) and overall survival (P =.004) by univariate analysis. Similarly, increased MVD in metastases, but not in primary tumors, was statistically significantly associated with diminished overall survival in these patients (P =.02). In multivariate analysis, the number of positive axillary lymph nodes and the presence of vascular hot spots in axillary lymph node metastases predicted decreased disease-free survival (P =.0001 and.02, respectively) and overall survival (P =.0001 and.007, respectively). All P values were two-sided.
Conclusion: This pilot study suggests that assessing neovascularization in axillary lymph node metastases may provide clinically useful information regarding survival in patients with primary breast cancer.