Standardized uptake value by positron emission tomography/computed tomography as a prognostic variable in metastatic breast cancer.

BACKGROUND: In this retrospective, single-institution study, the authors examine the maximum standardized uptake value (SUVmax) on positron emission tomography/computed tomography (PET/CT) images as a prognostic variable in patients with newly diagnosed metastatic breast cancer (MBC). METHODS: Patients with ≥1 metastatic lesion on PET/CT images that were obtained within 60 days of their MBC diagnosis between January 1, 2001 and December 31, 2008 were included. Patients were excluded if they had received chemotherapy ≤30 days before the PET/CT images were obtained. Electronic medical reports were reviewed to determine the SUVmax and overall survival. Because of intraindividual variation in the SUV by body site, separate analyses were conducted by metastatic site. Relationships between site-specific PET/CT variable tertiles and overall survival were assessed using Cox regression; hazard ratios for the highest tertile versus the lowest tertile were reported. RESULTS: In total, 253 patients were identified, and their median age was 57 years (range, 27-90 years). Of these, 152 patients (60%) died, and the median follow-up was 40 months. On univariate analysis, SUVmax tertile was strongly associated with overall survival in patients who had bone metastases (N = 141; hazard ratio, 3.13; 95% confidence interval, 1.79-5.48; P < .001). This effect was maintained on multivariate analysis (HR = 3.19; 95% confidence interval, 1.64-6.20, P = .002) after correcting for known prognostic variables. A greater risk of death was associated with SUVmax tertile in patients who had metastases to the liver (N = 46; hazard ratio, 2.07; 95% confidence interval, 0.90-4.76), lymph nodes (N = 149; hazard ratio, 1.1; 95% confidence interval, 0.69-1.88), and lung (N = 62; hazard ratio, 2.2; 95% confidence interval, 0.97-4.95), although these results were not significant (P = .18, P = .31, and P = .095, respectively). CONCLUSIONS: The current results indicate that PET/CT has value as a prognostic tool in patients with newly diagnosed MBC to bone.