Abstract
1429
Objectives The objective of this study was to prospectively evaluate FDG PET/CT for monitoring sunitinib therapy in patients with metastatic renal cell cancer (mRCC).
Methods Seventeen patients (mean age: 59.0 ± 11.6) prospectively underwent a baseline FDG PET/CT and interim PET/CT after 2 cycles (12 weeks) of sunitinib therapy. We measured SUVmax, total lesion glycolysis (TLG) and metabolic tumor volume (MTV) from baseline PET/CT and interim PET/CT, and the % decrease in SUVmax of lesion (%ΔSUVmax), the % decrease in TLG (%ΔTLG) and the % decrease in MTV (%MTV) between baseline and interim PET/CT, and Image results were validated by clinical follow-up.
Results At 12 months follow-up, 6/17 (35.3%) patients achieved PFS, while 11/17 (64.7%) patients were deemed to have progression of disease or recurrence within the previous 12 months. At baseline, PET/CT demonstrated metabolically active cancer in all cases. Using baseline PET/CT alone, all of the quantitative imaging metrics were statistically significantly higher in the cases with PFS less than 12 months when compared to cases with PFS greater than 12 months. Change of SUVmax, TLG and MTV between baseline and interim PET/CT were significantly higher in the case with PFS less than 12 months than the case with PFS more than 12 months. Otherwise, interim PET/CT showed no significant difference between the two survival groups regardless of the quantitative metric utilized including MTV and TLG.
Conclusions Baseline PET/CT appears to have potential in predicting PFS of 12 months for patients scheduled to undergo sunitinib therapy for mRCC. Change between baseline and interim PET/CT also appeared to have prognostic value but otherwise interim PET/CT performed after 12 weeks of sunitinib did not appear to be predictive of PFS.
Research Support Grant from the National Comprehensive Cancer Network (NCCN), Grant for general research support provided by Pfizer, Inc.