Change in contrast enhancement of HCC on 1-month follow-up CT after local radiotherapy: An early predictor of final treatment response

Background: The purpose of this study was to evaluate the change in contrast enhancement of HCC on 1-month follow-up CT after local radiotherapy (RT) as an early predictor of final treatment response. Materials: Fifty patients who underwent local RT for HCCs had both pre-RT and post-RT CT scans including 1-month follow-up CT. We assessed the final treatment response by using the change in maximal tumor size on 6-12-month follow-up CT scan after RT. We also evaluated the change in tumor enhancement between pre-RT and 1-month follow-up CT scans. Results: A final treatment response was achieved in 27 (54%) of 50 patients, who showed either a complete response (n = 11) or a partial response (n = 16). Compared with non-responsive patients (n = 23), responsive patients showed a significant decrease in tumor enhancement on 1-month follow-up CT after RT in both objective and subjective analyses (each P < 0.001). Conclusion: The change in contrast enhancement of HCC seen on the 1-month follow-up CT in patients after local RT may be used as an early predictor of final treatment response.