Power Doppler sonography of invasive breast carcinoma: does tumor vascularization contribute to prediction of axillary status?

Purpose: To prospectively compare unenhanced power Doppler sonographic findings of arterial vascularization of invasive breast carcinoma with histopathologic and immunohistochemical parameters and to determine whether tumor arterial vascularization contributes to prediction of axillary node status.

Materials And Methods: Ethics committee approval and informed consent were obtained. A total of 97 invasive breast carcinomas were prospectively studied with unenhanced power Doppler sonography before surgery. Lumpectomy or mastectomy with full axillary nodal dissection was performed. Sonographic tumor size and number of tumor arteries were correlated with axillary nodal status by means of logistic regression analysis. Tumor microvascularization was immunohistochemically assessed in a subset of 55 carcinomas. Sonographic variables were correlated with tumor arteries with a diameter larger than 300 mum and with the density and area of microvascularization. The kappa statistic and Bland-Altman agreement limits were used to measure agreement between techniques.

Results: Good agreement of sonographic and histologic findings regarding number of tumor arteries (kappa= 0.66, P < .001) and tumor size (P = .012) was observed. Multivariate analysis showed an independent relationship between probability of axillary metastasis, number of tumor arteries (P = .016), and sonographic tumor size (P = .035). A predictive model of axillary status was developed. The receiver operating characteristic curve was used to determine 0.2324 as the score to classify axillary nodal status. This score indicated high sensitivity (96.1%), low specificity (53.0%), and high negative predictive value (96.1%).

Conclusion: The number of arteries in invasive breast carcinoma detected with unenhanced power Doppler sonography and sonographic tumor size are independent predictors of axillary nodal status; these variables could contribute to reliable prediction of absence of axillary involvement on the basis of a mathematic model.