Alexander Martijn Theodorus Schmitz MD, Presenter: Nothing to Disclose

Joost Oudejans, Abstract Co-Author: Nothing to Disclose

Thijs Van Dalen, Abstract Co-Author: Nothing to Disclose

Paul Diest Van, Abstract Co-Author: Nothing to Disclose

Kenneth G.A. Gilhuijs PhD, Abstract Co-Author: Nothing to Disclose

In breast conserving therapy, selection of systemic therapy is based on prognostic markers from the resection specimen. This specimen is, however, no longer available after minimally invasive interventions such as MR-HIFU. Concordance in indication for systemic therapy pre- and post-operatively is, however, unknown. The aim of this study is to establish the diagnostic accuracy of pretreatment imaging and core biopsy to assess eligibility for systemic therapy. Secondly, to identify patient and tumor characteristics that affect the accuracy.

A retrospective study was performed on 97 consecutively included women (age 36-83 year) with primary invasive breast carcinoma on core biopsy (May 2009 - Dec 2010). Prognostic markers were obtained in two separate arms. Biopsy-arm: ER-status, tumor grade, largest tumor diameter (LD) (mammography, ultrasound, or MRI), age, and number of positive lymph nodes (ultrasound +/- fine needle aspiration). Resection-arm: ER-status, tumor grade, LD, age, and number of positive lymph nodes (sentinel node biopsy +/- axillary node dissection). The 10-year risk of mortality and relapse using Adjuvant! Online were combined to indicate systemic therapy according to the Dutch guidelines (oncoline.nl). McNemar tests were used to assess concordance between the two arms. Sensitivity, specificity, NPV and PPV of the biopsy-arm were calculated relative to the resection-arm (gold standard). Results were stratified in subgroups.

Overall, the biopsy-arm showed high specificity (98%) and PPV (97%) to indicate systemic therapy. However, the sensitivity (68%) and NPV (72%) were lower, suggesting risk of underestimating the indication for systemic therapy (p<0.001). This risk was less prominent in ER-negative tumors (n=15; sensitivity 92%; p<0.001), patients >70 years (n=15; NPV 91%; p<0,001), and tumors >2.0cm (n=34; NPV=83%; p<0.001).

Prior to MR-HIFU, positive indication for systemic therapy based on imaging and core biopsy is accurate. Risk of underestimation exists, however, with a negative test result, unless patients are >70 years, tumor size >2.0cm, or ER-status is negative.

Using pretreatment biopsy and imaging, subgroups of patients may be at risk of undertreatment by adjuvant therapy after minimally invasive breast cancer therapy.

Schmitz, A, Oudejans, J, Van Dalen, T, Diest Van, P, Gilhuijs, K, Pretreatment Imaging and Core Biopsy to Indicate Systemic Therapy after Minimally Invasive Breast Cancer Therapy: When Is It Safe? .  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13044238.html