Systemic therapies have two main aims – first to reduce the risk of future local recurrence and to treat possible distant metastatic disease. Toxic chemotherapy is not appropriate for pathologically pure DCIS, as there is only a 1–2% rate of subsequent metastases arising. Nevertheless as DCIS becomes more extensive, so the risk increases that pathologically occult microinvasion may be present and surgeons frequently perform SLNB for DCIS cases of > 30–40 mm in extent.

Most young women with invasive cancer are offered chemotherapy, with the Adjuvant! Online algorithm being widely used as a means of taking into account several important variables (tumor size, tumor grade, nodal status, receptor status) to provide an indication of overall % survival benefit. In older patients with EBC, chemotherapy may only offer significant additional survival benefit for ER-negative cancers.

Chapter outline

• Introduction

• Defining risk categories and identifying risk factors

• Women in the high-risk category

• Women in other risk subgroups

• Principles and limitations of XRM screening

• Performance of breast MRI in high-risk screening

• Principles and limitations of high-risk screening using breast MRI

• How long to screen for and at what internal

Introduction

The practical and the interpretative skills required to conduct a breast MRI program have been addressed in earlier chapters. In many centers, screening of women at high risk of breast cancer is now the commonest indication for performing breast MRI. This chapter will review breast screening concepts in general, and consider which women should be targeted for MRI screening. As gatekeepers of a precious resource, radiologists engaged in breast MRI screening, in close consultation with genetics experts and surgical colleagues, need to develop clear local guidelines on when MRI is considered appropriate. Other management options and issues relating to women at high risk of breast cancer are also addressed.

Chapter outline

• Introduction

• Breast anatomy

• Basic mammography and breast ultrasound

• Review of breast histopathology

• Molecular classification of breast cancer

• Mammographic correlates of pathologic subtypes

• Mammographic correlates of molecular subtypes

Introduction

While a basic level of knowledge is assumed, this chapter offers a brief review of breast anatomy, conventional breast imaging and breast pathology as useful background information to subsequent chapters. Over the last decade, the new molecular classification of breast cancer has assumed increasing clinical importance and has improved our understanding of pathogenesis. There is a developing appreciation of the concept that tumor biology may be more important in determining clinical outcomes than tumor burden. The concept of a broad division into low-grade and high-grade pathways of breast cancer development has important implications for management at a time when it is increasingly recognized that over diagnosis and overtreatment are significant issues in breast cancer screening programs. Some correlations between mammographic appearances and tumor pathology are highlighted, which are particularly pertinent in relation to BRCA gene mutation carriers, a high-risk subgroup where the use of screening MRI is becoming routine.

Preface

In the last decade, breast MRI has firmly established its place as a mainstream imaging technique, with providers experiencing rapid growth, particularly in high-risk screening and in the preoperative assessment of patients with known breast cancer.

It really is a great time to get involved. The great pioneers of breast MRI have worked tirelessly in the 25 years since contrast-enhanced breast MRI began, so that the key elements of technique and interpretation are now well understood. With high-gradient-strength MRI machines and technical advances in breast coil design, image quality has improved immeasurably, while computer-aided detection systems make the task of reporting breast MRI studies much quicker and easier.

The following tables are used with the permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition (2010) published by Springer Science and Business Media LLC, www.springerlink.com.

BRCA1 and BRCA2

These two genes together account for 5–10% of all breast cancer cases in most populations [16]. Both the BRCA1 and BRCA2 gene mutations are autosomal dominant so that any first degree relative (mother, sister, daughter) of an affected individual has a 50% chance of also carrying the mutation. In the presence of a strong family history but no known mutation, genetic testing is usually considered when computer modeling programs such as BCRAPRO or BOADICEA suggest at least a 10–15% chance that a mutation is present. Young women with high-grade triple-negative cancers are often also tested for a possible BRCA1 mutation even in the absence of an extensive family history.

When a suspicious family history is found, the first step in genetic testing is to take blood from an affected family member. This sample is subjected to full genetic testing for all known mutations of the BRCA1 and BRCA2 genes (about 2000 for each). Although expensive and time-consuming, the results often facilitate management of the entire family, because if a pathogenic mutation such as BRCA1 is identified, the remaining members of the family can then be offered predictive testing for that specific mutation, which is both quicker and less expensive.