The prediction value of lipiodol retention pattern on post-TACE CT scan for local progression of HCC after complete response

Abstract

Hepatocellular carcinoma (HCC) is classified as the sixth commonest cancer over the world and the fourth common in Egypt, representing the third leading cause of cancer-related mortality. Trans-arterial chemoembolization (TACE) is considered as one of the most effective treatment option for intermediate stage HCC. Lesions showing complete response (CR) after TACE can be classified according to their lipiodol retention pattern into complete (C-Lip, covering the entire tumor volume) or incomplete (I-Lip). The purpose of this study was to assess the prediction value of post-TACE lipiodol retention pattern on the local disease progression after complete response and thus to decide which patient should be carefully observed and considered to be incompletely treated. The study included 45 HCC lesions treated with TACE and showed complete response in the first follow-up CT performed 4–6 weeks after the procedure; 23 cases showed incomplete lipiodol retention pattern and 22 with complete lipiodol retention pattern which was carefully assessed on non-contrast CT images done 4 to 6 weeks after treatment. Follow-up CT was then performed every 3 months for at least 12 months or until local progression occurred. On the follow-up CT studies, 20 out of the 45 lesions showed persistent complete response (i.e., no local progression), while 25 of them showed local progression. Among the 25 cases with disease progression upon correlation with their lipiodol retention pattern, it was found that local progression occurred in 31.8% of tumors showed CR with complete lipiodol retention, as opposed to 78.2% of tumors showed CR with incomplete lipiodol retention with significant statistical difference and p value 0.010. Lipiodol retention pattern of HCC after TACE can predict the potential tumor local outcome. Lesions with incomplete lipiodol retention are at a higher risk of local tumor progression and therefore should probably observed and can be retreated; on the other hand, tumors with complete lipiodol retention have a much lower risk of local disease tumor progression.