Arterial Perfusion Imaging-Defined Aggressive Subvolume of Intrahepatic Cancer for Radiation Therapy
H Wang*, R Farjam , M Feng, R Ten Haken, T Lawrence, Y Cao, The University of Michigan, Ann Arbor, MITU-A-WAB-2 Tuesday 8:00AM - 9:55AM Room: Wabash Ballroom
Purpose: To assess whether subvolumes of tumors extracted from hepatic arterial perfusion images can predict treatment outcome in radiation therapy (RT) of intrahepatic cancer.
Methods: 21 patients who had 25 unresectable intrahepatic cancers and underwent focal RT were enrolled in a prospective IRB-approved study of dynamic contrast-enhanced (DCE) MRI. DCE MRI scans of the patients were acquired prior to RT, after delivering ~60% planned doses and 1 month after the completion of RT. Hepatic arterial perfusion images were quantified by using a dual-input single-compartment pharmacokinetic model of DCE MRI. Each treated tumor was classified into the subvolumes with low-normal, or high hepatic arterial perfusion. The changes in the subvolumes with high hepatic arterial perfusion and in the volumetric means of hepatic arterial perfusion over the whole tumors from pre-RT to during-RT were evaluated for differentiation of responsive and progressive tumors using Mann-Whitney U test. The performance of the early changes in the new metrics for predicting tumor progression following treatment was evaluated by receiver operating characteristic (ROC) analysis.
Results: Of the 25 tumors, 6 tumors in 5 patients progressed 5-21 months after the completion of RT, the other tumors responded to treatment. From pre-RT to during-RT, the tumor subvolumes with high hepatic arterial perfusion significantly increased (118%, p=0.007) in the progressive tumors compared to responsive ones. For predicting tumor progression, the change percentage in the tumor subvolume with high hepatic arterial perfusion had an area under curve (AUC) of 0.87 ± 0.09, while the change in mean hepatic arterial perfusion over the whole tumors had AUC of 0.85 ± 0.10.
Conclusion: The tumor subvolume with high hepatic arterial perfusion could be an early predictor for treatment outcome in RT of intrahepatic cancer, and could be a candidate for radiation boost. (Supported by NIH grant RO1CA132834)