MRI detection of distinct incidental cancer in women with primary breast cancer studied in IBMC 6883.
BACKGROUND
Prior single institution studies suggest MRI may improve the assessment of the extent of cancer within the breast, and thus reduce the risk of leaving macroscopic disease in the breast following breast conservation therapy. We report on the rate of MRI and mammography detection of foci of distinct incidental cancer in a prospective, multi center trial involving 426 women with confirmed breast cancer at 15 institutions in the US, Canada, and Germany.


METHODS
Women underwent mammography and MRI prior to biopsy of the suspicious index lesion. Additional incidental lesions (IL) greater than 2 cm from the index lesion that were detected by mammography and MRI were noted and characterized. Biopsy recommendations were associated with ILs given an assessment of suspicious or highly suspicous (BiRads 4 and 5). These assessments were considered a positive test.


RESULTS
MRI had a significantly higher yield of confirmed cancer ILs than mammography (0.18 (95%CI: 0.142-0.214) for MRI versus 0.072 (95%CI: 0.050-0.100) for mammography). The cancer ILs detected by MRI alone appeared to be similar to those detected by mammography with respect to size and histology. The percentage of biopsies of ILs that resulted in a cancer diagnosis was similar between the modalities (MRI 0.72(95%CI: 0.6-0.81); Mammography 0.85 (95%CI: 0.62-0.96)).


CONCLUSIONS
These results suggest that consideration needs to be given regarding the integration of breast MRI into the pretreatment evaluation of women seeking breast conservation therapy.
Schnall
Mitchell D
MD
Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. schnall@oasis.rad.upenn.edu
Blume
Jeffery
J
Bluemke
David A
DA
Deangelis
Gia A
GA
Debruhl
Nanette
N
Harms
Steven
S
Heywang-Köbrunner
Sylvia H
SH
Hylton
Nola
N
Kuhl
Christiane K
CK
Pisano
Etta D
ED
Causer
Petrina
P
Schnitt
Stuart J
SJ
Smazal
Stanley F
SF
Stelling
Carol B
CB
Lehman
Constance
C
Weatherall
Paul T
PT
Gatsonis
Constantine A
CA
D001706:Biopsy; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008327:Mammography; D008875:Middle Aged; D012680:Sensitivity and Specificity