Functional (PET/CT) compared to conventional (mammography [M], sonography [US], MRI) imaging: Defining novel assessment modalities for inflammatory breast cancer (IBC)

Abstract

600 Background: IBC is an aggressive frequently lethal form of breast cancer that is defined by sudden onset breast erythema often without an associated clinical or radiological breast mass. Tissue diagnosis remains problematic due to inability to define an area for biopsy. The aim of this study was to compare conventional [M, US, MRI] vs. functional imaging [PET/CT] in detecting a primary breast parenchymal lesion (BPL) at initial presentation of IBC. Methods: Patients (pts) with a new clinical diagnosis of IBC evaluated at the M. D. Anderson Cancer Center between January 2003 to December 2006 who had M, US, MRI, or PET/CT were included in this study. The visibility of a BPL and skin abnormality on each imaging modality was compared. Regional (axillary, supraclavicular, internal mammary) nodal disease confirmed by pathology was assessed at US and PET/CT. The presence of metastatic disease at diagnosis with PET/CT was documented. Results: Sixty-seven pts met eligibility criteria. Median age was 51 years, (range, 25 to 78). Of these, 61 (91%) had M, 62 (93%) had US, 21 (31%) had MRI, and 13 (19%) had PET/CT. By M, no BPL (mass or calcifications) was observed in 16% (10/61), skin-only abnormality (SOA) in 14% (9/61), and a BPL in 84% (51/61). By US, no BPL (mass or architectural distortion) and SOA were noted in 6% (4/62), and a PBL in 94% (58/62). By MRI, 21/21 (100%) showed malignant enhancing BPL and skin thickening. By PET/CT, 100% (13/13) showed hypermetabolic BPL and skin thickening. Pathologically confirmed regional nodal disease was diagnosed in 96% (59/62) by US and in 69% (9/13) by PET/CT. Distant metastases in the bone and lung were diagnosed in 15% (2/13) by PET/CT, one of which was visible on bone scan. Conclusions: MRI and PET/CT showed a primary BPL in all cases of IBC while conventional imaging (M and US) failed to reveal a BPL amenable to biopsy in up to 16%. US can diagnose regional nodal disease to facilitate loco-regional therapeutic planning. PET/CT provides additional information on distant metastasis and should be considered in the initial staging of IBC. No significant financial relationships to disclose.