Enhanced MRI predicts Ca treatment outcome.(Gynecology)

DENVER -- Assessment of tumor microvasculature by dynamic contrast-enhanced MRI permits early prediction of treatment outcome in patients with advanced cervical cancer, Nina A. Mayr, M.D., said at the annual meeting of the American Society for Therapeutic Radiology and Oncology.

These dynamic contrast-enhanced (DCE) MRI parameters provide significant added predictive value beyond the current preferred clinical prognostic factors, which are tumor stage, histology, and nodal status. Indeed, the MRI tumor microvasculature data permit prediction of treatment failure as early as 2 weeks into chemoradiation therapy, enabling physicians to alter treatment at midcourse in predicted poor responders, said Dr. Myer, director of the division of radiation oncology at Ohio State University, Columbus.

DCE MRI assesses both the structure and function of tumor microvasculature, particularly at the level of the capillary arterioles and in the extracellular interstitial space. Dr. Mayr has been instrumental in developing DCE MRI as a noninvasive prognostic tool for advanced cervical cancer. The clinical prognostic factors physicians have traditionally relied upon, she stressed, simply aren't informative enough.

"There's still a fair amount of variability with tumor stage and node status. Really, in the individual patient, response remains unknown. And once treatment fails, after-the-fact options are very limited," she said.

Dr. Mayr reported on 62 patients with stage IIB-IV disease that was treated with chemoradiation. They underwent DCE MRI studies before treatment, then at 2 weeks into therapy after receiving 20-25 Gy of radiation, and midway through therapy after having received 45-50 Gy. Mean follow-up was 3.5 years.

DCE MRI's greatest predictive power was at 2 weeks. Image signal intensity proved to be the key variable. Patients whose signal intensity was in the lowest 10% at 2 weeks had a 16-fold increased risk of local recurrence. A residual tumor volume shown by DCE MRI to be in the upper 10% at 2 weeks also independently predicted local recurrence, conferring a 7.3-fold increased risk.

These DCE MRI risk factors were more potent than the traditional ...