Predicting Control of Primary Tumor and Survival by DCE MRI During Early Therapy in Cervical Cancer

Abstract

Purpose-To assess the early predictive power of MRI perfusion and volume parameters, during early treatment of cervical cancer, for primary tumor control and disease-free-survival.Materials and Methods-Three MRI examinations were obtained in 101 patients before and during therapy (at 2-2.5 and 4-5 weeks) for serial dynamic contrast enhanced (DCE) perfusion MRI and 3-dimensional (3D) tumor volume measurement. Plateau Signal Intensity (SI) of the DCE curves for each tumor pixel of all 3 MRI examinations was generated, and pixel-SI distribution histograms were established to characterize the heterogeneous tumor. The degree and quantity of the poorlyperfused tumor subregions, which were represented by low-DCE pixels, was analyzed by using various lower percentiles of SI (SI%) from the pixel histogram. SI% ranged from SI2.5% to SI20% with increments of 2.5%. SI%, mean SI, and 3D-volume of the tumor were correlated with primary tumor control and disease-free-survival, using Student t-test, Kaplan-Meier analysis and log-rank test. The mean post-therapy follow-up time for outcome assessment was 6.8 years (range: 1.2-12.3 years).Results-Tumor volume, mean SI, and SI% showed significant prediction of the long-term clinical outcome, and this prediction was provided as early as 2-2.5 weeks into treatment. An SI5% of <2.05 and residual tumor volume of ≥30 cm 3 in the MRI obtained at 2-2.5 weeks of therapy provided the best prediction of unfavorable 8-year primary tumor control (73% vs. 100%, p=0.006) and diseasefree-survival rate (47% vs. 79%, p=0.001), respectively.Conclusions-Our results show that MRI parameters quantifying perfusion status and residual tumor volume provide very early prediction of primary tumor control and disease-free-survival. This functional imaging based outcome predictor can be obtained in the very early phase of cytotoxic therapy within 2-2.5 weeks of therapy start. The predictive capacity of these MRI parameters, indirectly reflecting the heterogeneous delivery pattern of cytotoxic agents, tumor oxygenation and the bulk of residual presumably therapy-resistant tumor, requires future study.

Assessment of Tumor Radioresponsiveness and Metastatic Potential by Dynamic Contrast-Enhanced Magnetic Resonance Imaging

“…Significant positive correlations have been observed between parameters describing the rate or magnitude of signal enhancement and tumor pO 2 or microvascular density (24)(25)(26). Furthermore, there is increasing evidence that poor signal enhancement is correlated with poor response to radiation treatment as a consequence of hypoxia-induced radiation resistance (26)(27)(28). However, the correlations are generally weak, perhaps because the analyses were based on semiquantitative parameters derived from signal intensity curves rather than quantitative parameters calculated from Gd-DTPA concentration curves by the use of adequate pharmacokinetic models.…”

Hypoxia-Induced Gene Expression in Chemoradioresistant Cervical Cancer Revealed by Dynamic Contrast-Enhanced MRI

“…Studies have suggested that DCE-MRI of cervical cancer depicts functional features associated with progressive disease (5)(6)(7)(8).…”

Added Value of Perfusion in Gynaecological Imaging

“…Quantitative analysis, where some studies postulated low perfusion is the lower 10th percentile of the signalintensity curve (SI 10%) [5,39], while other considered SI 15% is more specific [5,40].…”