Radiological–pathological correlation study of hepatocellular carcinoma undergoing local chemoradiotherapy and surgery

Background and Aims: Optimal response criteria and assessment timing were investigated through radiologic–pathologic correlation in hepatocellular carcinoma (HCC) treated with localized chemoradiotherapy (CRT). Methods: We reviewed 19 consecutive HCC patients who underwent surgical resection after radiotherapy and concurrent hepatic arterial infusion chemotherapy. Patients who received transarterial chemoembolization before RT or surgery were excluded from evaluation. Tumor diameters and total and enhancing tumor volumes were measured from CT images obtained 1, 3, 6, and 9 months after CRT. Percent changes calculated using size (RECIST and WHO) and enhancement criteria (mRECIST and EASL) were correlated with percent changes in total and enhancing tumor volumes, and with percent viable tumor in surgical specimens. Results: Median time between CRT and resection was 4.1 months (range, 1.5–15.4 months). CR and PR rates were 0 and 68% by RECIST, 0 and 63% by WHO, 53% and 37% by mRECIST, and 53% and 42% by EASL. Pathologic CR (pCR) rate was 52.6%. Radiologic criteria showed strong correlation with tumor volumes at 1 and 3 months after CRT; at 6 months, however, size and enhancement criteria showed strong correlation only with total and enhancing tumor volumes, respectively. Enhancement criteria were better predictors of pathologic response at all times including preoperative evaluation (RECIST: R ² = 0.303, P = 0.015 and WHO: R ² = 0.366, P = 0.006 vs. mRECIST: R ² = 0.760, P < 0.0001 and EASL: R ² = 0.768, P < 0.0001). Time interval >6 months before resection showed significant correlation with pCR (P = 0.013). Conclusions: We recommend using enhancement criteria in assessing tumor viability, especially if the tumor was to be resected <6 months after CRT.