sup 18^F-FDG PET/CT Findings and Circulating Tumor Cell Counts in the Monitoring of Systemic Therapies for Bone Metastases from Breast Cancer

• Published in: The Journal of nuclear medicine (1978) Vol. 51; no. 8; p. 1213
• Main Authors: De Giorgi, Ugo, Mego, Michal, Rohren, Eric M, Liu, Ping, Handy, Beverly C, Reuben, James M, Macapinlac, Homer A, Hortobagyi, Gabriel N, Cristofanilli, Massimo, Ueno, Naoto T
• Format: Journal Article
• Language: English
• Published: New York Society of Nuclear Medicine 01.08.2010
• Subjects: Breast cancer; Cancer therapies; Clinical medicine; Medical research; Multivariate analysis; Radiation therapy
• ISSN: 0161-5505; 1535-5667

Our objective was to compare the predictive significance of ^sup 18^F-FDG PET/CT findings and circulating tumor cell (CTC) count in patients with bone metastases from breast cancer treated with standard systemic therapy. Methods: Breast cancer patients with progressive bone-only metastatic disease without visceral metastases starting a new line of systemic therapy underwent ^sup 18^F-FDG PET/CT and had CTC counts determined before and during treatment. Disease status was reassessed by CTC count (≥5 vs. <5 CTC/7.5 mL of blood) and ^sup 18^F-FDG PET/CT approximately 2-4 mo after initiation of the new systemic therapy. Results: CTC counts at follow-up agreed with the ^sup 18^F-FDG PET/CT assessment in 43 (78%) of the 55 evaluable patients. Of the 12 patients with discordant CTC and ^sup 18^F-FDG PET/CT results, 8 (66%) had ≥5 CTCs, with no evidence of progressive disease at the time of the ^sup 18^F-FDG PET/CT study, whereas 4 (33%) had <5 CTCs, with evidence of progressive disease by ^sup 18^F-FDG PET/CT. ^sup 18^F-FDG PET/CT findings and follow-up CTC counts were found to be significantly associated with both progression-free survival (P = 0.02 and P < 0.0001, respectively) and overall survival (P = 0.02 and P = 0.01, respectively). In multivariate analysis, the ^sup 18^F-FDG PET/CT assessment remained as the only predictive factor for progression-free survival (P < 0.0001), whereas estrogen receptor status was the only predictive factor for overall survival (P = 0.01). Conclusion: ^sup 18^F-FDG PET/CT is a useful tool for therapeutic monitoring in patients with bone metastases from breast cancer. Prospective studies are needed to define the role of ^sup 18^F-FDG PET/CT and CTC in the setting of response discordance to establish bone-dominant disease as a tumor-response measurable disease. [PUBLICATION ABSTRACT]