SPONTANEOUS REGRESSION OF HEPATOCELLULAR CARCINOMA: FOCUSING IN THE ASSOCIATED RISK FACTORS.

Background: Spontaneous regression (SR) is defined as the partial or complete disappearance of a tumor, in the absence of a specific treatment. Evidence of the SR in hepatocellular carcinoma (HCC) is rare.

Objective: The authors aimed to review all the cases of SR of HCC in two reference centers of Southern Brazil, highlighting the main characteristics.

Methods: Data of all patients with HCC were retrospectively reviewed looking for the occurrence of SR in patients from two tertiary centers in Southern Brazil, in the last five years. The diagnosis of cirrhosis was established according to clinical, laboratory and imaging data, as well as upper endoscopy or histopathological examination when necessary. The diagnosis of HCC was based on typical findings according to radiologic criteria (LIRADS) or histopathological examination. Spontaneous regression was defined as a partial or complete involution of a HCC in the absence of a specific therapy.

Results: From all cases of HCC in the last 5 years (n=433), there were five cases of SR. Three (60%) were men, the mean age was 62.6 (50.0-76.0) years, and the etiology was HCV in 3 (60%). Complete regression was observed in three patients (60%), one patient (20%) presented partial regression, and one (20%) relapesed and died. The time of follow-up varied between 12 and 21 months. In this presentation, it was highlighted one case of SR observed after COVID-19 infection in a patient with cirrhosis. The possible mechanisms involved in this situation were reviewed, emphasizing the most common like hypoxia and immunological. There were also one patient submitted to a surgical procedure as a possible fator involved and three patients without obvious risk factors.

Conclusion: This phenomenon will possibly contribute to a better understanding of the pathophysiological mechanisms of HCC.