0:00

Our next topic is recall

0:02

from screening mammography.

0:05

And we have to remember that about

0:07

10 percent of patients who undergo

0:10

screening mammography will be recalled.

0:13

And the types of findings that we look for

0:16

on screening mammograms include asymmetries,

0:19

masses, calcifications, architectural

0:22

distortion, and enlarged lymph nodes.

0:26

So, you know, we have to be prepared

0:29

on the diagnostic imaging service

0:31

to evaluate each type of finding.

0:35

So we'll start with asymmetry.

0:37

And according to the BI-RADS atlas,

0:39

there are four types of asymmetry.

0:42

Just using the word asymmetry

0:44

refers to a one-view finding.

0:48

So either on the CC or the MLO view, but not both.

0:51

A focal asymmetry is seen on two views.

0:55

A developing asymmetry is new or increased

0:58

compared to the previous examinations.

1:00

And then a global asymmetry refers

1:02

to a larger area, usually at

1:04

least a quadrant of breast tissue.

1:08

It's seen on two views,

1:09

and it's often a normal variant.

1:14

So, for the one-view asymmetry, we know that these

1:17

are, um, often related to superimposed normal

1:20

breast tissue, um, about 80 percent of the time

1:24

from work, uh, done by Ed Sickles back in the '90s.

1:29

And Sickles in a 1998 study found a

1:34

1.8% malignancy rate,

1:35

and that was, uh, with 2D mammography.

1:38

A more recent study published

1:40

this year by Gong et al.

1:42

looked at tomosynthesis.

1:44

Recalls for one-view asymmetry

1:46

and found a 1.7% malignancy rate.

1:50

So it's interesting that, you know, many years

1:52

have passed and we've gone from 2D to 3D,

1:55

but the malignancy rate has stayed about the same.

1:57

So under 2% a developing

2:01

asymmetry is, is more concerning.

2:04

So this is a two-view asymmetry

2:06

that's new or increasing over time.

2:08

And there've been, uh, a few

2:10

different studies looking at this.

2:12

One of the seminal, uh, studies was

2:14

Liang and Sickles published in 2007.

2:18

This was looking at the malignancy rate

2:20

on 2D mammography, and they found a

2:22

12.8 percent malignancy rate on screening

2:26

mammograms recalled for developing asymmetry.

2:29

Um, Cheeseborough et al. in 2016.

2:30

56 00:02:32,659 --> 00:02:34,950 uh, showed a 15 percent malignancy

2:34

rate in cases found on 2D, and then

2:37

a more recent study by Liang et al.

2:40

published this year, 2022, found a 20

2:44

percent malignancy rate in cases found

2:46

on digital breast homosynthesis,

2:49

even among those with no ultrasound correlate.

2:52

So this is an important finding,

2:54

the developing asymmetry.

2:58

Our evaluation at Hopkins, we have

3:01

a slightly different approach for

3:03

asymmetry versus focal asymmetry.

3:05

So the, for the one-view finding, we usually

3:08

repeat the full CC or MLO view that showed the

3:11

finding because sometimes that alone eliminates

3:14

the problem, just a slightly different degree

3:17

of compression or slightly different positioning

3:20

of the tissue, um, can relieve that issue.

3:23

Um, we also do a spot compression view in the

3:26

projection that showed the finding and also a

3:28

full lateral view for focal asymmetry that's seen

3:32

on both views. We'll do spot compression in both

3:35

the CC and MLO views and a full lateral view.

3:39

At this point, we're about 90 to 95% tomosynthesis,

3:44

but sometimes, uh, we still have patients who

3:46

will have a 2D mammogram, either that's ordered

3:49

by their physician or, um, the patient prefers 2D.

3:53

So if the screening mammogram was 2D, then we will

3:56

consider starting with full tomosynthesis views.

3:59

Rather than doing those,

4:01

um, spot compression views.

4:03

And then ultrasound will be at

4:04

the radiologist's discretion.

4:08

So there are a lot of reasons for asymmetry.

4:10

Um, it could be superimposed normal

4:13

breast tissue, and frequently the

4:14

one-view asymmetries are just that.

4:17

Um, it could be related to a

4:18

variation of position or compression.

4:21

Um, often we'll see asymmetries, um,

4:24

occurring in the setting of hormonal change.

4:27

That, um, the patient has maybe gone

4:31

through menopause or begins to, um,

4:33

taking hormone replacement therapy or

4:35

has some other hormonal, uh, variation.

4:39

It could be related to a weight change.

4:41

The patient has lost weight or gained weight

4:43

and tissue becomes more or less, um, prominent

4:46

appearing on the mammogram related to that.

4:49

Um, and then there are actual lesions in the

4:51

breast that can cause, um, the finding of

4:55

asymmetry, including cysts, benign masses.

4:58

Um, frequently we'll see this entity called

5:01

PASH, pseudoangiomatous stromal hyperplasia, um,

5:05

fibrosis, breast cancer, either ductal carcinoma

5:08

in situ or invasive breast cancers, and lymphoma.