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Tomosynthesis and breast imaging update Dr Michael J Michell Consultant Radiologist King's College Hospital NHS Foundation Trust
BREAST CANCER – FLT PET shows different grades of tumour with the primary site Images courtesy of Wai Lup Wong, Paul Strickland Cancer Centre
Mount Vernon
Breast imaging:application of new technology
screening diagnosis/
assessment
local
staging
axilla response
to RX
systemic
disease
XRM ++ ++ ++
TOMO ? ++ ++ ?
CE-XRM ? ?
US ? ++ ++ ++ ++
CE-MRI ++ ++ ++
F MRI
MOL
+
CT/PET ++
Limitations of 2D mammography
• 3D information projected onto 2D image plane
superimposition of tissues
Clinical effect
- false positive cases screening recall
- false negative cases interval cancers
- mammographic features obscured
diagnostic uncertainty
understaging
DBT - technology
Hologic dimensions - 15 deg - 15 proj
Siemens innovation - 50 deg - 25 proj
GE - 40 deg - 15 proj
Sectra - 11 - continuous
IMS - 40 deg - non uniform sampling
DBT radiation dose 2V = up to 5 mGy . FFDM 2V = 4 mGy
reconstructed images are
displayed as 1mm slices
for viewing singly or in cine mode
number of slices varies
according to breast thickness
Accuracy of DBT recall from screening
bilateral 2D + tomo (combo)MLO/CC
Michell MJ et al, Clin Rad 2012; 67: 976-81
DBT - technical developments
• tomo guided biopsy
• synthetic 2D
• contrast tomo
• combined imaging
• CAD
Synthetic 2D combined with DBT has
equivalent accuracy compared to FFDM
+ DBT
Skaane P et al Radiology. 2014, Jan
Zuley M et al Radiology.2014, Jan
• images are courtesy of the following sites:
– Rose Medical Center, Denver, CO, USA
– Hôpital Privé d’Antony, Antony, FR
– Kaohsiung Veterans General Hospital, Taiwan
Contrast Mammography
Assessment of screen detected lesions
Questions
1. is there a lesion?
2. where is it?
3. what is the risk of malignancy?
4. tumour size
5. unifocal/multifocal?
6. what further tests are needed?
Lesions
changing appearances
Mammographic features viewed on DBT
Circums-
cribed
Mass
Spiculated
mass Distortion
Asymmetric
Density None (no
abnormality)
Ma
mm
og
rap
hic
featu
res v
iew
ed
o
n F
FD
M
Circumscribed
mass 0 11 0 6 11 28
Spiculated
mass 3 0 3 0 5 11
Distortion 1 5 0 4 13 23
Asymmetric
Density 19 10 0 0 57 86
None
(no abnormality) 13 11 12 2 0 38
Total 36 37 15 12 86 186
Iqbal A, Michell MJ et al RSNA 2011
Irregular mass on US
CB = Gd 3 IDC Palpable mass LT breast
- recalled from screening
Are all tumours
visible on DBT
King’s study:DBT vs spot compression mag views
• 355 lesions in 342 patients
• 104 malignant
82 benign
169 normal
7 radiologists
standard + DBT vs
standard + Mag
Clin Rad, accepted for publication 2014
Zuley M, et al Radiology:266 Jan 2013
DBT vs supplemental views for evaluation of non calcified lesions
217 lesions, 72 cancers
AUC DBT = 0.87 suppl views = 0.83 p<.001
Tumour size - Invasive Ductal Carcinoma
Invasive Ductal Carcinoma, n = 108
DBT 0.655
(0.551 to 0.759)
FFDM 0.591
(0.471to 0.711)
US 0.535
( 0.424 0.647)
Values are presented as CCC [rho_c, 95%
CI]; CCC = Concordance correlation
coefficient; Figures in parentheses are
95% confidence intervals.
Accuracy of tumour measurement
correln coeff
(a)
correln coeff
(b)
MRI 0.92 -
DBT 0.89 0.86
DM 0.83 0.71
US 0.77 0.85
(a)Luparia A, Mariscotti G et al Radiol Med. 2013
(b)Fornvik D, Zackrisson S et al Acta Radiol. 2010 51(3)
Tomosynthesis in diagnostic work up
- advantages vs spot compression
• whole breast imaged
• easier positioning
• some cancers less visible on spot compression
• 3D information on lesion position
• DBT in two projections recommended
• USS still necessary for soft tissue lesions
Diagnostic work up/ assessment
- current practice
• DBT for mammographic work
up of soft tissue lesions
• fine focus mag views for
microcalcification
DBT in screening trials
- OSLO - ( P Skaane)
- STORM - (S Ciatto )
- TOMMY - ( F Gilbert )
- MALMO - ( I Anderson )
OSLO Trial
• 36,000 women 50 - 69 years
• Recruitment 11/10 - 12/12
• Reading arms
FFDM, FFDM + CAD, FFDM + DBT, synth 2D + DBT
reading time - FFDM 45 secs
- Combo 91 secs
OSLO Trial : Comparison of digital mammography alone and
DM + tomosynthesis in a population based screening program P Skaane et al, Radiology, 2013 Jan
12,631 participants
DM 77 cancers 6.1/1000
DM+DBT 112 cancers 8/1000
27% increase in ca detection p =0.001 (95% CI 1.06-1.53)
40% increase in invasive cancers p < 0.001
Recall rate (prior to arbitration)
DM 6.1%
DM +DBT 5.3%
15% decrease recall rate p <0.001
7292 participants mean age – 58 yrs
Reading - 2D, 2D + 3D
Cancer detection
2D 39 cancers 5.3/1000 (95% CI 3.8-7.3)
2D + 3D 59 cancers 8.1/1000 (95% CI 6.2-10.4)
p<0.0001
Recall
Overall 395 (5.5%)
Conditional recall 254 (3.5%)
thelancet.com/oncology april 25 2015
Grade DM DM+DBT Diff
In situ low/int 4 4 0
high 17 16 -1
Invasive 1 17 32 15
2 29 35 6
3 9 13 4
Oslo Trial – screen detected cancers
MALMO 2 Trial
1V DBT vs 2V 2D Siemens
Preliminary results - 7500 women
2V DM 1V DBT
Cancer detection
/1000 screened
6.3 8.5
Recall rate
% screened
2.2 3.3
Zacrisson et al, ECR 2014
DBT in screening - expectations
• more screen detected cancers
• lower false positive recall rate
• ? one reader
BUT
What about ‘overdiagnosis’
Prospective RCT of tomosynthesis in screening
Control group - standard 2V FFDM
Study group - tomo + synthetic 2D
Primary end point - interval cancer rates
Sample size
30% improvement in cancer detection = 2-3/1000
UK interval cancer rate = 2.85 / 1000 36 mths
?intervention might reduce interval ca rate to 1.85/1000
For 90% power need 50,000 per arm
Prospective RCT of tomosynthesis in screening
Secondary endpoints
• cancer detection
• prognostic features
• recall rate
• one vs two readers
• economic analysis
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