Pathologic Correlation with Mammogram and MRI Size for

Primary Breast CarcinomaRichard D. Lovett, MD Jennifer K. Stedman

Rutland Regional Medical Center, University of Vermont College of Medicine, Fairfield University

Purpose

Current breast cancer screening practice is to employ physical examination, self examination, mammography

Magnetic Resonance Imaging (MRI) with contrast enhancement was demonstrated to be effective in 1989 for breast imaging by Kaiser and Heywang

Purpose

According to Bagley in 2003:– MRI accurately estimated the size of the breast

lesion 91% of the time, an accuracy level believed to be greater than conventional mammograghy

Purpose

To examine all women at RRMC, who underwent MRI preoperatively, to determine whether the Mammogram or the MRI more accurately determined the presence and size of the pathologic lesion. The time frame used was 2001 until May 2006

Materials and Methods

138– 0– 138– 152

– 56– 51– 27– 10– 4– 4

Patients– Male– Female– Lesions

Pathologic Size– 0-1cm– >1-2cm– >2-3cm– >3-4cm– >4-5cm– >5cm

Materials and Methods

Stage T1 (0-2cm) T2 (>2cm-5cm) T3 (>5cm)

107 (70%) 41 (27%) 4 (3%)

Materials and Methods

Women with mammogram and MRI done preoperatively from 2001 to 5/2006

Mammogram done by ACR accredited facility MRI done at RRMC

– Gadolinium enhancement– Dynamic contrast enhancement curves

Analysis of size and lesion by radiologist or radiation oncologist

Materials and Methods

Contrast enhanced MRI with breast cancer in the outer quadrant of the left breast

Images made with the subtracted gradient echo technique rather than the fat saturation technique

Materials and Methods

Dynamic enhancement curves plotted on the breast cancer with data points at 1 minute through 7 minutes after gadolinium injection

Materials and Methods

Patient with multifocal breast cancer in the right breast (the full extent of the breast cancer was not appreciated on the mammogram due to the patients young age (44)

Materials and Methods

Enhancement curves of many of the multifocal sites on this young woman

This patient decided on a mastectomy based on this data

Results

Comparison of Images to Pathologic Size

Table 2 Mammogram (%) MRI (%)

Image Size Equals Path Size (within 5mm)

55.5% 85.5%

Total Images Different

Than Path 44.5% 14.5%

Image Size Greater than 5mm Discordant with

Path

18% 11%

Image Modality Did Not Visualize Lesion

12.5% 3%

Image Modality Did Not Visualize All the Lesions

10% 0%

Could Not Measure the Image

4% .5%

Results

Mammogram vs. MRI

55.5

85.5

18

11 12.5

3

10

04

0.50

10

20

30

40

50

60

70

80

90

1

MM, MRI

% o

f tot

al le

sion

s

Mammo correct

% MRI correct

Mammo off >.5cm

MRI off >.5cm

Mammo NED

MRI NED

Mammo not detect alllesions

MRI not detect all lesions

Mammo could not measuresize

MRI could not measure size

Results- Pathologic Stage vs. Discordance Between Image and Pathology

Equal Discordant Not Seen

MammoT1 56% 27% 17%T2 59% 39% 2%T3 0% 100% 0%

MRIT1 87% 9% 4%T2 88% 10% 2%T3 25% 75% 0%

Results

MRI and Mammogram Size versus Pathologic Size

0

1

2

3

4

5

6

7

8

9

0 2 4 6 8 10

Pathologic Size (cm)

Imag

e Si

ze

MammogramMRI

Results

MRI and Mammogram Size versus Pathologic Size

0

1

2

3

4

5

6

7

8

9

0 2 4 6 8 10

Pathologic Size (cm)

Imag

e Si

ze MammogramMRILinear (Mammogram)Linear (MRI)

r =0.44r =0.64

Conclusions

The accuracy rate of MRI for predicting the size of the lesion is higher than the accuracy rate of mammogram 86% vs. 56% respectively

This finding is maintained for T1 and T2 lesions when staging is stratified

For T3 lesions, MRI is more accurate in predicting the size of the lesion, 25% to 0, however the small number of these lesions in the study precludes conclusions.

Conclusions

Mammography is more likely to image the breast cancer smaller than the true pathologic size

MRI with its contrast enhancement is more likely to image the lesion slightly larger than the pathologic size, presumed to be due to recruitment of perilesional blood vessels

Conclusions

Because the size of a lesion is one of the factors considered in the decision between conservation therapy and mastectomy, the increased accuracy of preoperative MRI scanning may impact on the surgical choice available to a woman with breast cancer.

Acknowledgements

Rutland Regional Medical Center– JC Biebuyck, MD– Allan Eisemann, MD– Daniel Mitchell, MD– Mike Nagar, RTT– James Rademacher, MD– Roshan Siva, MD

Harvard Medical School, Beth Israel Deaconess– Thomas Hill, MD– J. Anthony Parker, MD