Ricerc@Sapienza

PURPOSE:
To correlate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters to tumor grading and to assess their reliability in predicting pathological complete response (pCR) before neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC).

MATERIALS AND METHODS:
Forty patients (24 male; mean age, 67.3?±?8.1 years) with histologically proven LARC who had undergone 3-Tesla DCE-MRI before (MRI_1) and after CRT (MRI_2) between August 2015 and February 2016 were included in this retrospective study. DCE-MRI parameters at MRI_1 and MRI_2 were extracted by two board certified radiologists in consensus reading with Olea Sphere 2.3 software using the extended Tofts model. Based on DCE-MRI results, patients were divided in complete responders (CR) and non-complete responders (nCR) and the perfusion parameters were correlated to tumor grading and pCR.

RESULTS:
Wash-out and Kep at MRI_1 showed significant correlation with LARC grading (P?=?0.004 and 0.01, respectively). Ve showed a significant increase between MRI_1 (0.47?±?0.27) and MRI_2 (0.63?±?0.23; P?=?0.007). Ktrans measured at MRI_1 was significantly higher in CR (0.66?±?0.48) compared to nCR (0.53?±?0.34, P?=?0.02).

CONCLUSION:
Wash-out and Kep measured before CRT correlate with LARC grading. Ve changes during CRT, while Ktrans measured before CRT may predict the response to therapy. Therefore, DCE-MRI parameters can predict tumor aggressiveness and CRT efficacy, playing a role as imaging biomarkers in patients with LARC.