Transcript ACRIN PA 4006: Tomosynthesis Trial Update and Discussion

ACRIN Breast Committee
Fall Meeting 2010
4006: Comparison of Full-Field Digital Mammography with Digital Breast
Tomosynthesis Image Acquisition in Relation to Screening Call-Back Rate
Emily F. Conant, MD
Constantine Gatsonis, PhD
ACRIN Breast Committee
Digital Breast Tomosynthesis
Disclosures:
GE Support (P.I. E. Conant): A Multicenter Study to Test the Non-Inferiority
of Digital Breast Tomosynthesis (DBT) Compared to Full-Field Digital
Mammography(FFDM) in Detecting Breast Cancer
E.Conant: Consultant to Hologic
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Study Summary
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Limitations of Mammography
Tissue superimposition
Projection imaging
X-rays
Compression Plate
Breast
Detector
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Digital Breast Tomosynthesis
Digital Breast Tomosynthesis (DBT)
Multiple low dose digital mammographic images are obtain
along an arc and then reconstructed into a stack of images
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Digital Breast Tomosynthesis
Tomographic Imaging
X-rays
Compression Plate
Breast
Detector
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Tube
Rotation
Digital Breast Tomosynthesis
Vendors have varied approach to DBT:
• Image acquisition
– Angle of acquistion, number of images in arc
• Continuous arc image acquisition
• “Stop and shoot” image acquisition
• Stand alone screening tool versus adjunct to full field
digital mammography (FFDM)
– Single view MLO DBT (no FFDM)
– Two view DBT plus FFDM
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Digital Breast Tomosynthesis
• Preliminary experience has suggested that
digital breast tomosynthesis (DBT) may
provide:
– Better specificity leading to reductions in recall
rates
– Improvements in sensitivity and the depiction of
the extent of disease
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Digital Breast Tomosynthesis
Issues?
• Few published trials
• Results stress specifity as measured by reduction in
recall rates
• Most are single institution, single vendor
– Technical approach varies greatly by vendor…
Little published data on impact of tomosynthesis on
sensitivity in breast cancer screening
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Digital Breast Tomosynthesis
Multi-center trial of 1957 pts
• Compared FFDM and DBT recall rates
– 43% reduction in recall rate
Rafferty et al. RSNA 2007:SSG01-01
Single institution trial of 98 pts
•
Compared FFDM and DBT recall rate
- 40% reduction in recall rate
Poplack et al. AJR 2007;189(3):616-623
Single institution trial of 125 selected studies
•
FFDM alone, DBT alone and FFDM/DBT combo
- 30% decrease recall rate with combo, 10% DBT alone
Gur et al. AJR 2009;193:586-591
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Digital Breast Tomosynthesis
Two views versus one view tomo?
• Results
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22/34 (65%) both projections equal
4/34 (12%) much better seen on MLO projection
5/34 (15%) much better seen on CC projection
3/34 (9%) seen only on the CC projection
Imaging in both CC and MLO positions is optimal
Rafferty et al:RSNA 2006;SSG01-04
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Digital Breast Tomosynthesis
What about calcifications in DBT?
• 98 recalled cases
– “image quality of tomosynthesis was inferior to
diagnostic mammography” in characterization of calcs
Poplack et al. AJR 2007;189(3):616-623
• 119 DBT cases with calcifications
– Approx. 50%, DBT = FFDM
– Approx. 40%, DBT > FFDM
Kopans et al. RSNA 2008 SSJ01-02.
Motion artifact in DBT
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Hypothesis
• Digital breast tomography (DBT) will
improve the specificity of breast cancer
screening as measured by a reduction in
the call-back rate while maintaining the
sensitivity of cancer detection.
– This improved accuracy will be achieved by the
optimization of the imaging sequence and number
of views obtained at a capped radiation dose in
the combined DBT and 2-D screening sequence
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Eligibility and Sample Size
• Screening Group A (n=500) :
– Women presenting for screening > 25 yrs
• Enrichment Group B (n=50) :
– Women called back from FFDM screening for
diagnostic imaging
Total Accrual = 550 cases
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Study Design
• Standard of Care clinical study:
– 3 view digital mammogram
• Study Imaging:
– 2 view tomosynthesis (MLO and CC) and low dose 2D MLO
– Sequential read of study low dose 2-D CC view.
Studies read independently therefore,
call-backs determined independently
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Specific Aims
• Primary Aim:
– Compare recall rates of FFDM to limited DBT set
(Group A)
• Secondary Aims:
– To compare sensitivity of FFDM to the limited DBT
set (Groups A and B)
– To assess lesion-type characterization:
• To compare sensitivity and specificity by lesion-type (calc only
lesions versus soft-tissue lesions, as well as lesion subgroups:
masses, calcs, architectural distortions, asymmetries) in FFDM
versus DBT.
• To estimate the agreement of FFDM and DBT with the
determination of the adjudication committee on lesion-type
characterization.
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Additional Aims
• Secondary Aims, continued:
– To use the sequential interpretation results [Groups A and B] to
compare the two-view limited tomosynthesis set (with low-dose
MLO view alone) with the tomosynthesis plus set (addition of
low-dose CC view) on the basis of:
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•
•
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Call-back rate;
Identification of new lesion(s);
Lesion characterization; and
Triangulation
– To calculate and compare the radiation dose of the FFDM
and the DBT sets
– To identify the determinants of participant radiation dose and
clinical image quality, including factors such as kVp, mAs,
target/filter combination, and breast thickness and
composition
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Recruitment
• Patients to be recruited over a 1 year period
• Trial scheduled to open 10/6/10 at
Pennsylvania sites:
– Hospital of the University of Pennsylvania
– Einstein Medical Center
• Limited to one industry since only one vendor in PA – Hologic
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Future Tomosynthesis Trials?
Optimize imaging for tomosynthesis
• Which combinations of 3-D and possibly 2-D images?
• Decision based on risk/benefit for individual patient?
• Optimization of dose based on task?
Trial powered for sensitivity?
• High/intermediate risk patients (+/-MR)?
How do we best utilize tomosynthesis for
diagnostic imaging?
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