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Date:2018/06/13

Presenter: Yu-Ling Chen

Introduction

Although mammography is the only test with evidence demonstrating breast cancer

mortality reduction, its utility is challenged by false-positive recalls leading to additional

imaging and invasive benign biopsies, interval invasive cancers, and over diagnosis.

Screening breast magnetic resonance imaging(MRI) is recommended to augment

screening mammography for women at high breast cancer risk(eg, >20% life time risk).

screening mammography in women with a PHBC has limitations, with approximately 35%

of second breast cancers presenting as interval cancers within 1 year of a negative result

on a surveillance mammogram, with 5-year risk of interval invasive second breast cancer

varying widely across women.

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Objective

To evaluate biopsy rates and yield in the 90 days following screening

(mammography vs magnetic resonance imaging with or without mammography)

among women with and without a PHBC.

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Methods

This study included data from 6 Breast Cancer Surveillance Consortium(BCSC)

registries.

collect information on examinations performed at participating facilities in their defined catchment areas and link this information to local pathology databases and state tumor registries or regional Surveillance, Epidemiology, and End Results programs to obtain population-based cancer data.

Demographic and breast cancer risk factor data including age, first-degree

family history, and time since last mammogram were collected using a self-

reported questionnaire completed at each screening examination.

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Methods

We included women with at least 1 screening digital mammogram or screening

breast MRI from 2003 to 2013.

without a PHBC

a screening examination (mammogram or MRI) was defined as a bilateral

examination without the same type of imaging in the prior 9 months.

with a PHBC

screening examinations included examinations in women without the following:

prior bilateral mastectomy, imaging of the same type (mammogram or MRI)

within the prior 60 days, or a breast cancer diagnosis within the prior 6months.

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Magnetic resonance imaging episodes included screening MRI with or without a screening mammogram because MRI alone really means MRI with adjunct mammography outside the 30-day window.

Methods

Biopsy intensity

based on the most invasive biopsy performed (surgical biopsy greater than core

biopsy greater than fine-needle aspiration) within the 90-day follow-up period.

Biopsy result

based on the most invasive finding found from any biopsy (invasive greater than

ductal carcinoma in situ [DCIS] greater than high-risk benign greater than benign).

We calculated the BCSC 5-year risk score to evaluate imaging limited to women

without a PHBC.

categorized into low (<1.00%), average (1.00%-1.66%), intermediate (1.67%-2.49%),

and high/very high (≥2.50%) risk.

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Statistical Analysis

Frequency distributions

For age-adjusted rates, logistic regression models were fit for each

outcome of interest (eg, core biopsy) including age as a covariate.

predicted probabilities were combined using weights based on the age

distribution of the overall sample.

A propensity-matched sensitivity analysis to tightly control for potential

confounding between women receiving different episode types.

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Results

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n=36,318 n=78,073n=2,323 n=3,419

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Propensity matching

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Discussion

Strengths

1. biopsy intensity and findings from 2040558 mammogram episodes and 8436 MRI

episodes from 136 BCSC community and academic radiology facilities linked to

pathology databases, as well as state and regional tumor registries.

2. Our study includes a geographically and racially representative US population

sample, likely reflecting US clinical radiology practice.

Limitations

1. there may be misattribution of the most significant pathological findings with the

most invasive biopsy finding, but we believe that it would be unlikely for women to

undergo a more intensive biopsy after identifying DCIS or invasive cancer.

2. There is hope that tomosynthesis will decrease the rate of false-positive results and

improve biopsy yield. We were unable to evaluate tomosynthesis in this study.

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Conclusions

In women with and without a PHBC, we observed clinically and statistically

higher biopsy rates in the 90 days following screening MRI compared with

mammography episodes, which resulted in lower rates of DCIS and invasive

cancer findings following MRI.

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