90Y-PET/CT-based dosimetry after selective internal radiation therapy predicts outcome in patients with liver metastases from colorectal cancer

Hugo Levillain; Ivan Duran Derijckere; Gwennaëlle Marin; Thomas Guiot; Michaël Vouche; Nick Reynaert; Alain Hendlisz; Bruno Vanderlinden; Patrick Flamen

doi:10.1186/s13550-018-0419-z

⁹⁰Y-PET/CT-based dosimetry after selective internal radiation therapy predicts outcome in patients with liver metastases from colorectal cancer

EJNMMI Res. 2018 Jul 13;8(1):60. doi: 10.1186/s13550-018-0419-z.

Authors

Hugo Levillain¹, Ivan Duran Derijckere², Gwennaëlle Marin³, Thomas Guiot², Michaël Vouche⁴, Nick Reynaert³, Alain Hendlisz⁵, Bruno Vanderlinden³, Patrick Flamen²

Affiliations

¹ Department of Nuclear Medicine, Jules Bordet Institute, Université Libre de Bruxelles, Rue Héger-Bordet 1, B-1000, Brussels, Belgium. hugo.levillain@bordet.be.
² Department of Nuclear Medicine, Jules Bordet Institute, Université Libre de Bruxelles, Rue Héger-Bordet 1, B-1000, Brussels, Belgium.
³ Department of Medical Physics, Jules Bordet Institute, Université Libre de Bruxelles, Rue Héger-Bordet 1, B-1000, Brussels, Belgium.
⁴ Department of Radiology, Hôpital St-Pierre, Jules Bordet Institute, Université Libre de Bruxelles, Rue Héger-Bordet 1, B-1000, Brussels, Belgium.
⁵ Department of Digestive Oncology, Jules Bordet Institute, Université Libre de Bruxelles, Rue Héger-Bordet 1, B-1000, Brussels, Belgium.

Abstract

Background: The aim of this work was to confirm that post-selective internal radiation therapy (SIRT) ⁹⁰Y-PET/CT-based dosimetry correlates with lesion metabolic response and to determine its correlation with overall survival (OS) in liver-only metastases from colorectal cancer (mCRC) patients treated with SIRT. Twenty-four mCRC patients underwent pre/post-SIRT FDG-PET/CT and post-SIRT ⁹⁰Y-PET/CT. Lesions delineated on pre/post-SIRT FDG-PET/CT were classified as non-metabolic responders (total lesion glycolysis (TLG)-decrease < 15%) and high-metabolic responders (TLG-decrease ≥ 50%). Lesion delineations were projected on the anatomically registered ⁹⁰Y-PET/CT. Voxel-based 3D dosimetrywas performed on the ⁹⁰Y-PET/CT and lesions' mean absorbed dose (Dmean) was measured. The coefficient of correlation between Dmean and TLG-decrease was calculated. The ability of lesion Dmean to predict non-metabolic response and high-metabolic response was tested and two cutoff values (Dmean-under-treated and Dmean-well-treated) were determined using ROC analysis. Patients were dichotomised in the "treated" group (all the lesions received a Dmean > Dmean-under-treated) and in the "under-treated" group (at least one lesion received a Dmean < Dmean-under-treated). Kaplan-Meier product limit method was used to describe OS curves.

Results: Fifty-seven evaluable mCRC lesions were included. The coefficient of correlation between Dmean and TLG-decrease was 0.82. Two lesion Dmean cutoffs of 39 Gy (sensitivity 80%, specificity 95%, predictive-positive-value 86% and negative-predictive-value 92%) and 60 Gy (sensitivity 70%, specificity 95%, predictive positive-value 96% and negative-predictive-value 63%) were defined to predict non-metabolic response and high-metabolic response respectively. Patients with all lesions Dmean> 39 Gy had a significantly longer OS (13 months) than patients with at least one lesion Dmean < 39 Gy (OS = 5 months) (p = 0.012;hazard-ratio, 2.6 (95% CI 0.98-7.00)).

Conclusions: In chemorefractory mCRC patients treated with SIRT, lesion Dmean determined on post-SIRT ⁹⁰Y-PET/CT correlates with metabolic response and higher lesion Dmean is associated with prolonged OS.

Keywords: 90Y-PET/CT; Chemorefractory mCRC; Dosimetry; Metabolic response; SIRT; Survival.