Lipiodol retention pattern after TACE for HCC is a predictor for local progression in lesions with complete response

Abstract

Background: To evaluate the predictive value of the lipiodol retention pattern for local progression of HCC with a complete response (CR) on CT according to mRECIST criteria after a first session of conventional chemoembolization (cTACE).

Methods: From January 2014 to May 2016 all consecutive patients undergoing a first cTACE session for HCC were identified. Inclusion criteria were the presence of ≤3 HCCs and available pre- and post-cTACE CT. Tumor response was classified according to mRECIST criteria. The analysis focused on tumors with a CR. The lipiodol retention pattern in these tumors was classified as complete (C-Lip, covering the entire tumor volume), or incomplete (I-Lip). Local progression was defined as the reappearance of areas of enhancement on arterial-phase images with washout on portal/delayed phase images within 2 cm from treated tumors on follow-up CT.

Results: The final population included 50 patients with 82 HCCs. A total of 46 (56%) HCCs were classified with a CR, including 16 (35%) with I-Lip, and 30 (65%) with C-Lip. After a median follow-up of 14 months (3.2-35.9 months), 15/16 (94%) and 10/30 (30%) of I-Lip and C-Lip HCCs showed local progression on CT, respectively (p < 0.001), with no significant difference in the time to progression (mean 11.1 ± 2 vs. 13.4 ± 3 months for I-Lip and C-Lip, respectively p = 0.51).

Conclusions: HCCs with incomplete lipiodol retention after a first cTACE session have a high risk of local progression even when there is a CR according to mRECIST, and should be considered to be incompletely treated.

Keywords: Carcinoma, hepatocellular; Chemoembolization, therapeutic; Ethiodized oil.

Fig. 1

Study design. cTACE: conventional Transarterial Chemoembolization. C-Lip: Complete lipiodol retention, HCC: Hepatocellular Carcinoma. I-Lip: Incomplete lipiodol retention, mRECIST: Modified Response Evaluation Criteria in Solid Tumors

Fig. 2

Schematic representation of lipiodol retention patterns on precontrast CT after cTACE

Fig. 3

Local progression of an HCC showing a complete response according to mRECIST with incomplete lipiodol retention in a 59 yr-old female with HCV related cirrhosis. a baseline CT image obtained during hepatic arterial phase (HAP) shows a hyperehanced HCC in the right liver lobe. b and c first follow-up CT images showing the lesion presenting with incomplete lipiodol retention on a precontrast image (b), while images obtained during HAP (c) show no residual enhancement of the lesion. Millimetric lipiodol depositions were depicted in the right liver, suggesting the presence of pre-existing yet undetected small tumor foci. This CT showed the appearance of a lesion in the left liver lobe (not shown in the figure), for which the patient underwent a second TACE session targeting only the left liver lobe. d-f 3 months follow-up CT images obtained during precontrast (d), HAP (e) and delayed (3′) phase (f) show the reappearance of a hyperenhancing nodular portion on HAP (e) with washout on delayed (3′) phase (f) consistent with local progression (arrow)

Fig. 4

Absence of local progression of an HCC showing a complete response according to mRECIST with complete lipiodol retention in an 83 yr-old male with HBV related cirrhosis. a baseline CT image obtained during hepatic arterial phase (HAP) shows a hyperenhancing HCC in the left liver lobe. b and c first follow-up CT images showing the lesion presenting with complete lipiodol retention on the precontrast image (b) and no residual enhancement on HAP (c). d-e 24 months follow-up CT images obtained during unenhanced (d) and HAP (e) show that the nodule has decreased in size with persistent complete lipiodol retention in the lesion. No enhancing lesion in noticed on HAP (e)