Evaulation of response to TARE treatment in advanced liver malignancy by Yittrium-90 (⁹⁰Y) Time of Flight PET/CT: Comparison with pretreatment ^99mTc-MAA SPECT.

Objectives ⁹⁰Y microsphere PET/CT is an emerging imaging modality to evaluate post therapeutic status after radioembolization. ^99mTc MAA SPECT is a strong modality to simulate distribution of ⁹⁰Y microsphere before actual administration. We evaluate the prognostic predictiive abilities of ⁹⁰Y microsphere PET/CT and ^99mTc MAA SPECT with other clinical prognosis factors.

Methods Retrospective review of 29 HCC patients who underwent TARE and ⁹⁰Y microsphere PET/CT were performed. All patients were firstly treated by radioembolization. Tumor to normal ratios which were measured on two images and other prognosis factors including Child pugh score, CLIP, TNM stages, tumor size, administration doses were analyzed for progression free survival. Criteria of 2.51 in TNR value of ⁹⁰Y PET/CT were set for grouping the patients and group comparison was performed for progression free survival (PFD) and other factors.

Results In univariate analyasis, TNR value of ⁹⁰Y PET/CT, portal vein thrombosis, administration doses, CT size showed significances for PFD (respectively p value was 0.016, 0.006, 0.008, 0.005) as well as TNM stages and CLIP scores. In group comparison, the higher TNR PET/CT group showed favorable PFD, higher tendency of tumor thrombosis and higher TNR SPECT. (p = 0.008, 0.034, 0.034 respectively).

Conclusions ⁹⁰Y PET/CT is clinically feasible and predictive for progression free survival as much reasonably as other prognostic factors. As a post-therapeutic imaging for TARE routine using of ⁹⁰Y PET/CT is suggested for early prediction of patient prognosis.

Research Support This study was partly supported by the research grant for R & D for Clinical and Translational Research, HI13C1611, Korea Health Industry Development Institute, Ministry of Health and Welfare, Republic of Korea.