Appearance of untreated bone metastases from breast cancer on FDG PET/CT: importance of histologic subtype

• Published in: European journal of nuclear medicine and molecular imaging 2015-10, Vol.42 (11), p.1666-1673
• Main Authors: Dashevsky, Brittany Z., Goldman, Debra A., Parsons, Molly, Gönen, Mithat, Corben, Adriana D., Jochelson, Maxine S., Hudis, Clifford A., Morrow, Monica, Ulaner, Gary A.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Bone Neoplasms - diagnosis; Bone Neoplasms - diagnostic imaging; Bone Neoplasms - secondary; Breast cancer; Breast Neoplasms - pathology; Cardiology; Female; Fluorodeoxyglucose F18; Humans; Imaging; Medicine; Medicine & Public Health; Metastasis; Middle Aged; Multimodal Imaging; Neoplasm Grading; Nuclear Medicine; Oncology; Original Article; Orthopedics; Positron-Emission Tomography; Radiology; Retrospective Studies; Tomography, X-Ray Computed
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-015-3080-z

Purpose To determine if the histology of a breast malignancy influences the appearance of untreated osseous metastases on FDG PET/CT. Methods This retrospective study was performed under IRB waiver. Our Hospital Information System was screened for breast cancer patients who presented with osseous metastases, who underwent FDG PET/CT prior to systemic therapy or radiotherapy from 2009 to 2012. Patients with invasive ductal carcinoma (IDC), invasive lobular carcinoma (ILC), or mixed ductal/lobular (MDL) histology were included. Patients with a history of other malignancies were excluded. PET/CT was evaluated, blinded to histology, to classify osseous metastases on a per-patient basis as sclerotic, lytic, mixed lytic/sclerotic, or occult on CT, and to record SUVmax for osseous metastases on PET. Results Following screening, 95 patients who met the inclusion criteria (74 IDC, 13 ILC, and 8 MDL) were included. ILC osseous metastases were more commonly sclerotic and demonstrated lower SUVmax than IDC metastases. In all IDC and MDL patients with osseous metastases, at least one was FDG-avid. For ILC, all patients with lytic or mixed osseous metastases demonstrated at least one FDG-avid metastasis; however, in only three of seven patients were sclerotic osseous metastases apparent on FDG PET. Conclusion The histologic subtype of breast cancer affects the appearance of untreated osseous metastases on FDG PET/CT. In particular, non-FDG-avid sclerotic osseous metastases were more common in patients with ILC than in patients with IDC. Breast cancer histology should be considered when interpreting non-FDG-avid sclerotic osseous lesions on PET/CT, which may be more suspicious for metastases (rather than benign lesions) in patients with ILC.