Prediction of breast cancer size by ultrasound, mammography and core biopsy.

Neoadjuvant chemotherapy and non-surgical tumor ablation rely upon imaging studies to determine tumor size. In this study the accuracy of ultrasound (US) mammography and core biopsy in determining tumor size was examined in 202 patients with Stages I and II breast cancer. The most accurate single modality for determining tumor size was mammography with a correlation coefficient of 0.66, followed by US (r = 0.48) and core biopsy (r = 0.28). Size measurements were less accurate in lobular than ductal cancers. The combination of the three modalities understaged 25% of the tumors > 1cm in size, and overstaged 10% of those < 1cm. The inability to accurately determine tumor size has important implications for the use of non-surgical ablation.