Michael J. Michell MBBCH, Presenter: Nothing to Disclose

Asif Iqbal MBBS, Abstract Co-Author: Nothing to Disclose

Rema Wasan MBBCH, Abstract Co-Author: Nothing to Disclose

Abdel Douiri PhD, Abstract Co-Author: Nothing to Disclose

Sara Mombelloni MD, Abstract Co-Author: Nothing to Disclose

Lisa Marie Meacock MBBS, Abstract Co-Author: Nothing to Disclose

David Evans MD, Abstract Co-Author: Nothing to Disclose

Clare Peacock MBBS, Abstract Co-Author: Nothing to Disclose

Juliet Claire Morel, Abstract Co-Author: Nothing to Disclose

Christopher Peter Lawinski MPhil, Abstract Co-Author: Nothing to Disclose

Accurate measurement of breast tumour size is crucial for staging and treatment planning. The aim of this study is to compare the accuracy of two imaging modalities with tumour size on the final surgical histology.

A prospective study was carried out in 128 consecutive patients diagnosed with breast cancer either following screening or presentation with breast symptoms. Patients who underwent neo-adjuvant chemotherapy were excluded. A Hologic Selenia Dimensions machine was used to acquire co-registered two dimension digital mammography (2DM) and digital breast tomosynthesis (DBT) images. Tumour diameter in the largest single dimension was recorded on cranio-caudal and medio-lateral-oblique projections by specialist radiologists with no prior knowledge of the surgical pathology. The agreement between the two imaging modalities and pathology was analysed using the methods described by Bland-Altman. Scatter plots and Pearson Correlation Coefficient (PCC) were generated to produce predictive values for subgroup lesions by mammographic features.

In the cohort of 128 lesions, 91 were soft tissue lesions and 37 micro-calcifications. Of the 91 soft lesions, 41 were spiculated masses, 25 well circumscribed masses, 15 distortions and 10 asymmetric densities. For the total population (n=128), DBT was less biased (0.003, sd=0.33, 95%CI) than 2DM (0.009, sd=0.39, 95% CI) and the percentage error for 2DM was higher (53%) than DBT (45%) demonstrating that DBT was significantly more accurate in determining tumour size. In the subgroups, the strength of correlation between imaging modality and histology was summarized by PCC with the following corresponding values: spiculated mass DBT(0.951) and 2DM(0.786), well circumscribed mass DBT(0.918) and 2DM(0.865), distortion DBT(0.893) and 2DM(0.796), asymmetric density DBT(0.963) and 2DM(0.903), micro-calcification DBT(0.776) and 2DM(0.750).

The study shows that DBT is superior to 2DM in predicting the histological tumour size, because DBT demonstrates the margins and extents of the mammographic lesions more clearly. This is critical information for prospective treatment planning by the multi-disciplinary team.

Accurate preoperative local staging is essential for the modern approach to management of primary breast cancer.

Michell, M, Iqbal, A, Wasan, R, Douiri, A, Mombelloni, S, Meacock, L, Evans, D, Peacock, C, Morel, J, Lawinski, C, A Comparison of the Accuracy of Digital Breast Tomosynthesis with Two Dimension Digital Mammography in Measurement of Breast Tumour Size.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9014770.html