SOUTHEAST ASIAN J TROP MED PUBLIC HEALTH Vol 32 No. 3 September 2001 452 INTRODUCTION Hepatitis B virus (HBV) infection is con- sidered a leading cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC) in Southeast Asia, China and sub-Saharan Africa (Lee, 1997). Currently, interferon (IFN) is widely used for treatment of chronic HBV infection in most countries. The aims of IFN therapy are to suppress or eradicate HBV, to diminish necroinflammation and to reduce the risk of cirrhosis and HCC (Perrillo, 1993). Among patients treated for 3-6 months, its therapeutic LONG-TERM EFFECT OF INTERFERON THERAPY ON INCIDENCE OF CIRRHOSIS AND HEPATOCELLULAR CARCINOMA IN THAI PATIENTS WITH CHRONIC HEPATITIS B Pisit Tangkijvanich 1 , Duangporn Thong-ngam 2 , Varocha Mahachai 3 , Nusont Kladchareon 3 , Pongspeera Suwangool 4 and Pinit Kullavanijaya 3 1 Department of Biochemistry, 2 Department of Physiology, 3 Gastroenterology Unit, Department of Medicine, 4 Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand Abstract. The aim of this study was to assess the long-term effects of interferon (IFN) therapy on the incidence of disease progression to cirrhosis and hepatocellular carcinoma (HCC) in Thai patients with chronic hepatitis B. Sixty-seven patients with hepatitis B e antigen (HBeAg)- positive chronic hepatitis B who received IFN therapy were retrospectively analyzed. The average duration of follow-up was 59.4±30.9 months (ranging from 20 to 119 months). Seventy-two untreated patients with comparable clinical data and mean duration of follow-up served as a control group. During follow-up, 24 (35.8%) treated and 7 (9.7%) untreated patients had a sustained loss of HBeAg. However, none of the treated patients or controls became negative for hepatitis B s antigen (HBsAg). Among treated patients, the response was independent of type and dose of IFN, as well as the presence of steroid priming. In addition, 1 of 24 (4.2%) sustained responders and 6 of 43 (14%) non-responders progressed to cirrhosis whereas 16 of 72 (22.2%) in the control group progressed to such sequelae. The overall incidence of new cirrhosis in sustained responders was significantly lower than in the control group (p=0.04). HCC appeared in 11 cirrhotic patients: 9 (12.5%) in the control group and 2 (4.7%) of the non-responders, whereas none of the sustained responders developed HCC. The average period to detection of HCC was 70.5±12.4 months for non-responders and 65.3±27.6 months for the control group, with no significant differences between these groups. In conclusion, our data suggest that IFN therapy might prevent the progression of cirrhosis and the development of HCC in patients with chronic hepatitis B. These beneficial effects were particularly observed in those who achieved a sustained virological response to treatment. Correspondence: Pisit Tangkijvanich, Department of Biochemistry, Gastroenterology Unit, Department of Medicine, Chulalongkorn University, Bangkok 10330, Thailand. efficacy rate is approximately 30-40% in terms of virological and histological remission (Wong et al, 1993; Hoofnagle and DiBisceglie, 1997). Furthermore, previous studies have suggested that loss of HBeAg in chronic HBV infection, whether due to IFN therapy or occurring spontaneously, is associated with improved clinical outcome (Niederau et al, 1996; Lau et al, 1997; Fattovich et al, 1997). However, it is still unclear whether IFN therapy could prevent the development of cirrhosis and HCC in patients with chronic hepatitis B. Thus, the main aim of the current study was to evaluate retrospectively the long-term beneficial effects of IFN therapy on the incidence of cirrhosis and HCC among Thai patients with chronic hepatitis B.