Size of Hepatocellular Carcinoma as a Predictor of Radiologic Response to Transarterial Chemoembolization

Background: Hepatocellular carcinoma (HCC) is common in Egypt and is expected to rise. Transarterial chemoembolization (TACE) is the most common treatment modality as a standard of care for intermediate stage HCC. Lesion size is a decisive factor in management of HCC. Large size is hypothesized to be a prognostic factor against complete radiologic response. Objective: To assess the value of lesion size in predicting radiologic response to TACE. Material and Methods: Forty seven HCCs were assessed for its distribution of lipiodol after TACE. Multiphase computed tomography (CT) was done 1 month after TACE to assess Radiologic response. HCC was classified according to the size 5cm, 5-10cm and 10cm in diameter. Results: Lesions size ranged from 6mm to 15cm with a median of 7.3cm. Twenty five lesions (53.2%) were 5cm in diameter. Nine lesions (19.2%) were cm in diameter. Using modified RECIST, complete response was noted in 13 lesions (27.7%), partial response in 25 lesions (53.2%) and stable disease in 9 lesions (19.1%) one month after TACE. Lipiodol covered !75% of the lesion in 30 lesions (63%) and 75% in 13 lesions (27.7%) and 0% in 4 lesions (8.5%). Eight out of 9 lesions 10cm in diameter (88%) and 17 out of 25 lesions 5cm in diameter (68%) showed Lipiodol defects one month after TACE. A diameter 1 0cm was significantly correlated with incomplete Radiologic response (p-value 0.0002). A diameter of 5cm was not significantly correlated with Radiologic response. Lesion size 10cm was predictive of incomplete response showing a positive predictive value (PPV), prevalence weighted likelihood ratio (pwLR+), post test probability and odds ratio of 88.7% (95% Confidence interval (CI) 50.7-99.4%), 7.85 (95% CI 1.24-51.5), 95.4% (compared with pretest probability of 72.3%) and 20.7: 1 (compared with pretest odds ratio of 2.6: 1) respectively. Lesion size 5cm did not predict complete radiologic response as the PPV, pwLR+, post test probability and odds ratio were 32.2% (95% CI 15.7-53.6), 0.47% (95% CI 0.25-0.89), 15.4% (compared with a pretest probability of 27.6%) and 0.18: 1 (compared with pretest odds ratio of 0.38) respectively. Conclusion: HCC 10cm in diameter are very likely to show lipiodol defects after TACE. Lesions 5cm are not in advantage towards complete response.