Pharmacokinetic parameters derived from dynamic contrast enhanced MRI of cervical cancers predict chemoradiotherapy outcome

Abstract

PurposeTo assess the prognostic value of pharmacokinetic parameters derived from pre-chemoradiotherapy dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) of cervical cancer patients. Materials and methodsSeventy-eight patients with locally advanced cervical cancer underwent DCE-MRI with Gd-DTPA before chemoradiotherapy. The pharmacokinetic Brix and Tofts models were fitted to contrast enhancement curves in all tumor voxels, providing histograms of several pharmacokinetic parameters (Brix: ABrix, kep, kel, Tofts: Ktrans, νe). A percentile screening approach including log-rank survival tests was undertaken to identify the clinically most relevant part of the intratumoral parameter distribution. Clinical endpoints were progression-free survival (PFS) and locoregional control (LRC). Multivariate analysis including FIGO stage and tumor volume was used to assess the prognostic significance of the imaging parameters. ResultsABrix, kel, and Ktrans were significantly (P<0.05) positively associated with both clinical LRC and PFS, while νe was significantly positively correlated with PFS only. kep showed no association with any endpoint. ABrix was positively correlated with Ktrans and νe, and showed the strongest association with endpoint in the log-rank testing. kel and Ktrans were independent prognostic factors in multivariate analysis with LRC as endpoint. ConclusionsParameters estimated by pharmacokinetic analysis of DCE-MR images obtained prior to chemoradiotherapy may be used for identifying patients at risk of treatment failure.