Prediction of response to chemoradiation therapy in squamous cell carcinomas of the head and neck using dynamic contrast-enhanced MR imaging

Abstract

Background and purpose: Tumor microenvironment, including blood flow and permeability, may provide crucial information regarding response to chemoradiation therapy. Thus, the objective of this study was to investigate the efficacy of pretreatment DCE-MR imaging for prediction of response to chemoradiation therapy in HNSCC.

Materials and methods: DCE-MR imaging studies were performed on 33 patients with newly diagnosed HNSCC before neoadjuvant chemoradiation therapy by using a 1.5T (n = 24) or a 3T (n = 9) magnet. The data were analyzed by using SSM for estimation of K(trans), v(e), and tau(i). Response to treatment was determined on completion of chemoradiation as CR, with no evidence of disease (clinically or pathologically), or PR, with pathologically proved residual tumor.

Results: The average pretreatment K(trans) value of the CR group (0.64 +/- 0.11 minutes(-1), n = 24) was significantly higher (P = .001) than that of the PR (0.21 +/- 0.05 minutes(-1), n = 9) group. No significant difference was found in other pharmacokinetic model parameters: v(e) and tau(i), between the 2 groups. Although the PR group had larger metastatic nodal volume than the CR group, it was not significantly different (P = .276).

Conclusions: These results indicate that pretreatment DCE-MR imaging can be potentially used for prediction of response to chemoradiation therapy of HNSCC.

Fig 1.

A, Representative regions of interest shown on a T1WI of the neck acquired 10 minutes after injection of the contrast agent. Regions of interest are drawn on a carotid artery (A) and a metastatic node (N). B, Mean time courses of estimated relaxation rates from the 2 regions of interest in A are plotted against time. Circles and crosses represent actual measurement data points from the selected artery and the node, with the lines connecting the points. Note the region of interest used for the node is only to demonstrate the typical enhancement pattern and temporal resolution of the data. The actual pharmacokinetic analysis was performed for each voxel.

Fig 2.

Representative parametric maps of a CR patient who showed no viable tumor on pathology from the surgically removed nodes. The arrow on the T2WI image indicates the tumor node studied. The T2W, T1W, and CE images in the top row are windowed to have similar image contrast. The SSM parameter maps are shown by using overlaid color images on an area around the metastatic node indicated by the arrow in the T2WI. The background image of the color maps is a T1W CE image.

Fig 3.

Scatterplots of volume and pharmacokinetic model parameters of 2 patient groups: CR (n = 24) and PR (n = 9). Individual parameters within each patient group are plotted in their own descending orders.

Fig 4.

Comparison of patients scanned at 1.5T. There are 17 and 7 patients for the CR and PR groups, respectively. The bars represent the mean values and the error bars represent the standard errors. The asterisk represents a significant (P < .05, 2-tailed t test with unequal variance) difference from the CR mean value.

Fig 5.

Comparison of pretreatment K^trans values of the patients who received conventional chemotherapy (n = 17 and 7 for CR and PR, respectively) and those who received immunotherapy with an EGFR-targeting drug, cetuximab (n = 7 and 2 for CR and PR, respectively). The vertical bars represent the mean values, and the error bars represent the SDs.