Multimodality Breast Cancer Screening in Women with a Familial or Genetic Predisposition

I Trop,N Larouche,M.H Mayrand,L Lalonde,J David,D Provencher

doi:10.3747/co.v17i3.494

Abstract

Women with a predisposition for breast cancer require a tailored screening program for early cancer detection. We evaluated the performance of mammography (MG), ultrasonography (US), and magnetic resonance imaging (MRI) screening in these women. In asymptomatic women either confirmed as BRCA1/2 carriers, or having a greater than 30% probability of being so as estimated by brcapro [Berry D, Parmigiani G. Duke SPORE (Specialized Program of Research Excellence) in Breast Cancer. 1999], we conducted a prospective comparative trial consisting of annual MRI and MG, and biannual US and clinical breast examination. All evaluations were done within 30 days of one another. For each screening round, imaging tests were independently interpreted by three radiologists. The study enrolled 184 women, and 387 screening rounds were performed, detecting 12 cancers (9 infiltrating, 3 in situ), for an overall cancer yield of 6.5%. At diagnosis, 7 infiltrating cancers were smaller than 2 cm (T1); only 1 woman presented with axillary nodal metastases. All tumours were negative for the human epidermal growth factor receptor 2. Of the 12 cancers, MRI detected 10, and MG, 7; US did not identify any additional cancers. The overall recall rate after MRI was 21.8%, as compared with 11.4% for US and 16.1% for MG. Recall rates declined with successive screening rounds. In total, 45 biopsies were performed: 21 as a result of an US abnormality; 17, because of an MRI lesion; and 7, because of a MG anomaly. In high-risk women, MRI offers the best sensitivity for breast cancer screening. The combination of yearly MRI and MG reached a negative predictive value of 100%. The recall rate is greatest with MRI, but declines for all modalities with successive screening rounds.

Highlights

It was estimated that, in 2009, 22,700 Canadian women would receive a diagnosis of breast cancer, and 5400 would die from the disease 1
About 50% of breast cancers in high-risk families can be attributed to deleterious BRCA1 and BRCA2 mutations, found respectively on chromosomes 17q21 and 13q12–13
Given the evidence that women at high risk for breast cancer may benefit from newer imaging modalities, we introduced in a controlled fashion a multimodal screening program for high-risk women at the Centre Hospitalier de l’Université de Montréal

Summary

Introduction

In 2009, 22,700 Canadian women would receive a diagnosis of breast cancer, and 5400 would die from the disease 1. About 50% of breast cancers in high-risk families can be attributed to deleterious BRCA1 and BRCA2 mutations, found respectively on chromosomes 17q21 and 13q12–13. Both genes are inherited in an autosomal-dominant fashion with incomplete penetrance 3,4. The presence of a germ-line mutation in either of these genes confers on a woman a 50%–85% lifetime risk of developing breast cancer, mostly early-onset 2 and often aggressive 3,5–11. Women with a predisposition for breast cancer require a tailored screening program for early cancer detection. We evaluated the performance of mammography (mg), ultrasonography (us), and magnetic resonance imaging (mri) screening in these women

Methods

Results

Discussion

Conclusion