Abstract No. 575 LIRADS 4/5 lesions less than 2 cm: watch or treat? Understanding the natural history

To understand the epidemiology of LIRADS 4 (LR4) and 5 (LR5) lesions under 2 cm. All LR4 and/or LR5 lesion(s) under 2 cm in cirrhotic patients were identified retrospectively at a single institution from 2015 to 2018. Those with previous HCC therapy or a LR 4/5 lesion greater than or equal to 2 cm were excluded. For lesions pre-2016 when standardized reports with LI-RADS were not used at our institution, images were reviewed and graded by a radiologist using the current LI-RADS criteria to identify appropriate subjects. Age, gender, cirrhosis etiology, size and number of lesions, LIRADS grade on presentation, time to LR5 progression or resolution, tumor markers, liver disease indicators (MELD score, ascites, and hepatic encephalopathy), and time to therapy, tumor recurrence and transplant were collected. A total of 84 LR4/5 lesions were identified in 69 patients. The average age of patients was 63, 70% (48/69) were male, and 77% (53/69) had HCV cirrhosis. The mean sodium MELD score was 11, 48% (33/69) had evidence of ascites or required medication for ascites control, and 39% (27/69) required medication to control hepatic encephalopathy. 82% (57/69) presented with a solitary LR 4 or LR 5 lesion under 2 cm, whereas the remainder had on average 2.2 lesions at presentation. 88% (61/69) underwent treatment with locoregional treatment, resection or transplant after on average 168 days of follow-up (66% (40/61) within 6 months and 92% 56/61 within a year). 12% (8/69) did not undergo treatment: 38% (3/8) due to lesion resolution and 63% (5/8) due to lesion nonprogression over on average 444 days follow-up. For patients that underwent treatment, 28% (17/61) developed on average 1.4 new lesions between presentation and treatment. 77% (47/61) underwent locoregional therapy (LRT) as their initial treatment, most commonly transarterial therapy (47%, 22/47) and microwave ablation (45%, 21/47). 60% of these patients (28/47) developed a recurrence on average 454 days post-treatment. Of the 14 patients who underwent initial surgical treatment, 14% (2/14) had benign pathology. Overall, 37% (25/69) went on to receive a transplant on average 610 days after initial presentation. Although most LR4 and LR5 lesions smaller than 2 cm are very early-stage HCC and receive treatment, a significant portion are benign lesions and resolve on their own or remain stable over on average for more than a year.