Correlation of preoperative ultrasound and mammographic measurement of malignant breast masses with operative histology

Introduction

Preoperative assessment of breast cancer patients is by physical examination, mammography and ultrasound. Mammography and ultrasound measurements inform treatment regimes and prognostic estimates. Our aim was to determine the accuracy of imaging measurement of malignant breast masses in our Trust.

Methods

Screening and symptomatic women with breast cancer who had surgery between October 2008 and May 2009 were identified from multidisciplinary team records. The largest dimension of abnormal tissue/ breast mass on any projection/probe orientation was documented for mammography and/or ultrasound. Measurements were compared with the largest tumour dimension on final histological analysis of excised tumour.

Results

Records were available for 100 patients with invasive breast cancer (66% (66/100) invasive without DCIS, 34% (34/100) invasive with DCIS). Overall size of the malignancy measured at both mammography and ultrasound correlated with histological tumour size (r = 0.54 and r = 0.56, respectively). This correlation was less high for overall size of malignancy when associated with DCIS. Mammography with DCIS (r = 0.37) versus mammography without DCIS (r = 0.77); ultrasound with DCIS (r = 0.52) versus r = 0.68 for invasive cancers without DCIS. Multiple regression analysis showed that the combination of mammogram and ultrasound is an effective means of estimating size of malignancy in the presence of a mass (r ² = 0.67).

Conclusions

The combination of mammography and ultrasound is an effective means of predicting tumour size; it is more accurate for tumours without DCIS. There is a tendency towards size underestimation, more so for ultrasound than mammography.