PURPOSE: To evaluate outcome after radium-223 dichloride therapy (Ra-223) and to determine if skeletal tumor burden on whole-body 18F-Fluoride-PET/CT can be used as a predictive biomarker of survival in patients treated Ra-223.
PATIENTS AND METHODS: Forty-two patients with hormone-refractory prostate cancer underwent Ra-223 and a baseline fluoride-PET/CT scan. Fluoride-PET/CT parameters were generated, including maximum SUV of the hottest lesion (hSUVmax), average SUV of disease (Mean10), and skeletal tumor burden indices of total fluoride skeletal metastatic lesion uptake (TLF10) and total volume of fluoride avid bone metastases (FTV10). Overall survival (OS) was the primary end point. Secondary end points were progression-free survival (PFS) and skeletal related event (SRE).
RESULTS: Skeletal tumor burden indices (TLF10 and FTV10) derived from fluoride-PET/CT at baseline were highly correlated and significant independent predictors of OS (P = 0.0212; HR = 5.990; 95%CI =1.306- 27.475). A TLF10 cutoff value of 8000 discriminated survivors from non-survivors after Ra-223 (with TLF10 values below 8000 the median OS was not estimated while with TLF10 > 8000, the median OS was 6.67 months). Visual analysis, Mean10, and hSUVmax were not predictors of OS or PFS. Mean10 was found to be a significant univariate predictor of the odds of having a SRE (P =0.0445; OR=1.30; 95%CI = 1.006- 1.681), with a Mean10 >19 increasing the risk of SRE.
CONCLUSION: Skeletal tumor burden on baseline fluoride-PET/CT is a predictive biomarker of OS and the risk of a SRE in patients treated with Ra-223.
Written by:
Etchebehere E, Araujo JC, Fox PS, Swanston NM, Macapinlac HA, Rohren EM Are you the author?
The University of Texas MD Anderson Cancer Center, United States; University of Texas M.D. Anderson Cancer Center, United States.
Reference: J Nucl Med. 2015 Jun 11. (Epub ahead of print)
doi: 10.2967/jnumed.115.158626
PubMed Abstract
PMID: 26069307