BACKGROUND: Locoregional therapies (LRTs) are treatments to achieve local control of hepatocellular carcinoma (HCC). Correlation between radiologic response to LRT and degree of induced tumor necrosis is not well understood. The aim of this study was to evaluate different levels of radiologic response after pre-liver transplant (LT) LRT and its correlation with percentage of tumor necrosis on explanted histopathology.
METHODS: Institutional Review Board approved LT database was queried for treated HCC in patients undergoing LT. Radiologic response was evaluated to predict tumor necrosis in the explanted liver. Tumor response was evaluated 1 to 3 months after LRT with computed tomography or MRI via Response Evaluation Criteria in Solid Tumors (RECIST), and European Association for the Study of the Liver (EASL) guidelines. LRT was repeated as needed until time of LT. Histological tumor necrosis was graded as complete (100%), partial (50%-99%), or poor (<50%).
RESULTS: Between 2002 and 2011, 128 patients (97 men and 31 women) received pre-LT LRT including transarterial therapy (93), radiofrequency ablation (20), or combination of both (15). The mean age of the patients was 58±9 years. Their mean follow-up was 35±27 months. The median waitlist time was 55 days. One hundred (78%) patients had HCC within the Milan criteria at the initial radiologic diagnosis. Nineteen (15%) of the patients had complete tumor necrosis on histopathology analysis. Fifty (39%) of the patients exhibited partial necrosis, 52 (41%) showed poor or no necrosis and 7 (5%) showed progressive disease. The overall pre-LT radiologic staging was correlated with explant pathology in 73 (57%) of the patients. Underestimated tumor stage was noted in 49 (38%) patients, and overestimated tumor stage in 6 (5%) patients. The post-LT 3-year overall survival and disease free survival were 82% and 80%, and the rates for complete and partial tumor necrosis were 100% vs 78% (P=0.02) and 100% vs 75% (P=0.03), respectively.
CONCLUSIONS: In the current era, interpretation of radiologic response after LRT for HCC does not correlate accurately with histologic tumor necrosis. Total tumor necrosis is the goal of LRT; therefore, evolution in its performance is needed. Similarly, ways to predict therapy induced tumor necrosis via radiological investigation need to be improved.