Abstract No. 22 Predictors of intrahepatic recurrence of hepatocellular carcinoma following percutaneous microwave ablation of tumors larger than 3 cm

To identify the predictors of local recurrence and distant intrahepatic recurrence following microwave ablation of hepatocellular cancer larger than 3 cm 74 cases of microwave ablations for HCC >3 cm in size were included from a single institution. Data was collected from EMR and PACS. Mean age was 66 (SD 4.2) and the mean maximal tumor dimension was 4.2 cm (SD 1.2 cm). The mean distance of the tumors from diaphragm and the capsule were 2.5 (SD 2.6) and 0.5 (SD 0.9) cm, respectively. In 25 cases (33.7%), the tumor was < 1cm from diaphragm. In 45 cases (60.8%) a large vessel was located within 1 cm from the tumor margin. The mean AFP was 155.5 (224). Mean red cell distribution width was 14.9%. The mean platelet/albumin ratio was 2.8 (1.48). There were 44 (59.4%) cases of total recurrences of which 30 (40.5%) were local recurrences over a mean follow up period of 20 months. Tumors over 3.5 cm had a significantly higher proportion of recurrence (40.7 vs 73.3%, P = 0.03). Both maximal tumor dimension (P = 0.04) and the least distance from diaphragm (0.03) were independent predictors of recurrence on multivariate regression analysis. In HCC over 3 cm, the maximal tumor dimension and the proximity of the tumor to the diaphragm are predictors of recurrence following microwave ablation. Tumors over the size of 3.5 cm have significantly higher rates of recurrence.