San-Lin You

Decreased Incidence of Hepatocellular Carcinoma in Hepatitis B Vaccinees: A 20-Year Follow-up Study

BACKGROUND Hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma. This population-based study aimed to investigate whether prevention of hepatocellular carcinoma by the universal Taiwanese HBV vaccine program, launched in July 1984, has extended beyond childhood and to identify the predictors of hepatocellular carcinoma for vaccinated birth cohorts. METHODS Data on 1958 patients with hepatocellular carcinoma who were aged 6-29 years at diagnosis in Taiwan between 1983 and 2004 were collected from two national hepatocellular carcinoma registries. Age- and sex-specific incidence among vaccinated and unvaccinated birth cohorts were analyzed by using Poisson regression models. All statistical tests were two-sided. Records of 64 hepatocellular carcinoma patients and 5 524 435 HBV vaccinees who were born after the initiation of the vaccination program were compared for HBV immunization characteristics during infancy and prenatal maternal hepatitis B surface antigen (HBsAg) and e antigen (HBeAg) serostatus. RESULTS Hepatocellular carcinoma incidence was statistically significantly lower among children aged 6-19 years in vaccinated compared with unvaccinated birth cohorts (64 hepatocellular cancers among vaccinees in 37 709 304 person-years vs 444 cancers in unvaccinated subjects in 78 496 406 person-years, showing an age- and sex-adjusted relative risk of 0.31, P < .001, for persons vaccinated at birth). The risk of developing hepatocellular carcinoma for vaccinated cohorts was statistically significantly associated with incomplete HBV vaccination (for those who received fewer than three doses of HBV vaccine, odds ratio [OR] = 4.32, 95% confidence interval [CI] = 2.34 to 7.91); with prenatal maternal HBsAg seropositivity (OR = 29.50, 95% CI = 13.98 to 62.60); with prenatal maternal HBeAg seropositivity (with administration of hepatitis B immunoglobulin at birth, OR = 5.13, 95% CI = 2.24 to 11.71; and without it, OR = 9.43, 95% CI = 3.54 to 25.11). CONCLUSION The prevention of hepatocellular carcinoma by this HBV vaccine extends from childhood to early adulthood. Failure to prevent hepatocellular carcinoma results mostly from unsuccessful control of HBV infection by highly infectious mothers.

Chronic Hepatitis C Virus Infection Increases Mortality From Hepatic and Extrahepatic Diseases: A Community-Based Long-Term Prospective Study

BACKGROUND The study aimed to evaluate the risk of hepatitis C virus (HCV) infection on hepatic and extrahepatic deaths. METHODS A cohort of 23 820 adults aged 30-65 years old were enrolled during 1991-1992. The seromarkers hepatitis B surface antigen (HBsAg), anti-HCV, and serum HCV RNA levels at study entry were tested. The vital status was ascertained through computerized linkage with national death certification profiles from 1991 to 2008. RESULTS There were 19,636 HBsAg-seronegatives, including 18,541 anti-HCV seronegatives and 1095 anti-HCV seropositives. Among anti-HCV seropositives, 69.4% had detectable serum HCV RNA levels. There were 2394 deaths that occurred during an average follow-up period of 16.2 years. Compared with anti-HCV seronegatives, anti-HCV seropositives had higher mortality from both hepatic and extrahepatic diseases, showing multivariate-adjusted hazard ratio (95% confidence interval) of 1.89 (1.66-2.15) for all causes of death; 12.48 (9.34-16.66) for hepatic diseases; 1.35 (1.15-1.57) for extrahepatic diseases; 1.50 (1.10-2.03) for circulatory diseases; 2.77 (1.49-5.15) for nephritis, nephrotic syndrome, and nephrosis; 4.08 (1.38-12.08) for esophageal cancer; 4.19 (1.18-14.94) for prostate cancer; and 8.22 (1.36-49.66) for thyroid cancer. Anti-HCV seropositives with detectable HCV RNA levels had significantly higher mortality from hepatic and extrahepatic diseases than anti-HCV seropositives with undetectable HCV RNA. CONCLUSIONS Monitoring HCV RNA in anti-HCV seropositives is essential for the prediction of mortality associated with hepatitis C.

A retrospective study on malignant neoplasms of bladder, lung and liver in blackfoot disease endemic area in Taiwan

A total of 69 bladder cancer, 76 lung cancer and 59 liver cancer deceased cases and 368 alive community controls group-matched on age and sex were studied to evaluate the association between high-arsenic artesian well water and cancers in the endemic area of blackfoot disease (BFD), a unique peripheral vascular disease related to continuous arsenic exposure. According to a standardized structured questionnaire, information on risk factors was obtained through proxy interview of the cases and personal interview of the controls. A positive dose-response relationship was observed between the exposure to artesian well water and cancers of bladder, lung and liver. The age-sex-adjusted odds ratios of developing bladder, lung and liver cancers for those who had used artesian well water for 40 or more years were 3.90, 3.39, and 2.67, respectively, as compared with those who never used artesian well water. Multiple binary logistic regression analyses showed that the dose-response relationships and odds ratios remained much the same while other risk factors were further adjusted.

Aflatoxin exposure and risk of hepatocellular carcinoma in Taiwan

To investigate the carcinogenic effect of environmental aflatoxin exposure, 56 cases of hepatocellular carcinoma (HCC) diagnosed between 1991 and 1995 were identified and individually matched by age, sex, residence and date of recruitment to 220 healthy controls from the same large cohort in Taiwan. Blood samples were analyzed for hepatitis B and C viral markers and for aflatoxin‐albumin adducts; urine was tested for aflatoxin metabolites. We obtained information about socio‐demographic characteristics, habitual alcohol drinking, cigarette smoking and diet in a structured interview. Hepatitis B virus surface antigen (HBsAg) carriers had a significantly increased risk for HCC. After adjustment for HBsAg serostatus, the matched odds ratio (ORm) was significantly elevated for subjects with high levels of urinary aflatoxin metabolites. When stratified into tertiles, a dose‐response relationship with HCC was observed. The ORm for detectable aflatoxin‐albumin adducts was not significant after adjustment for HBsAg serostatus. HBsAg‐seropositive subjects with high aflatoxin exposure had a higher risk than subjects with high aflatoxin exposure only or HBsAg seropositivity only. In male HBsAg‐seropositive subjects, adjusted ORs were 2.8 (95% confidence interval [Cl] = 0.9–9.1) for detectable compared with non‐detectable aflatoxin‐albumin adducts and 5.5 (Cl = 1.3–23.4) for high compared with low urinary aflatoxin metabolite levels. Our results suggest that environmental aflatoxin exposure may enhance the hepatic carcinogenic potential of hepatitis B virus. A large‐scale study will be needed to evaluate the effect of aflatoxin exposure on HBsAg non‐carriers.

Transmission of hepatitis C virus in Taiwan: Prevalence and risk factors based on a nationwide survey

A nationwide community‐based survey on hepatitis C virus (HCV) was carried out in seven townships in Taiwan. A total of 11,904 men aged 30–64 years were recruited for testing for antibodies against HCV (anti‐HCV) by second‐generation enzyme immunoassay. A total of 272 seropositive cases and 282 seronegative controls were interviewed to explore risk factors for HCV infection in the study areas. Spouses of 214 seropositive cases were identified to assess the concordance of seropositivity of anti‐HCV between spouses; genotypes of HCV were also tested in 26 couples who were both seropositive. A significant geographic variation in seroprevalence of anti‐HCV was observed in the study townships (1.6–19.6%). Blood transfusions, medical injections, acupuncture and tattooing were related to an increased anti‐HCV seroprevalence showing multivariate‐adjusted odds ratios of 8.6, 2.5, 3.1, and 2.2, respectively, with corresponding population attributable risk percentages of 25%, 57%, 16%, and 3%, respectively. The anti‐HCV prevalence in spouses of index cases (24%) was significantly higher than that observed in the general population of the study areas (4%). However, a striking interspousal discrepancy in HCV genotypes (20/26 = 77%) was observed among both seropositive couples. Common exposures to medical injections and acupuncture were reported by 15 (58%) of these couples. This study identified some endemic areas of HCV infection in Taiwan. Iatrogenic factors were common vehicles for HCV infection, and a concordance of anti‐HCV seropositivity between spouses may primarily be due to extrafamilial iatrogenic infectious sources in study areas. J. Med. Virol. 59:290–296, 1999.

Cancer Trends in Taiwan

Cancer is becoming a more important health problem in Taiwan with aging of populations and changes in lifestyles. This indicates that a population-based cancer registration database is essential to providing informative data on cancer prevention and policy setting. The Taiwan Cancer Registry was launched in 1979 and all reporting hospitals were mandated to submit cancer data to the central cancer registry following the enactment of the Cancer Control Act in 2003. The National Health Insurance program in Taiwan has successfully provided quality health care, comprehensive benefits and convenient access to treatment. Most cancers had a rapidly increasing incidence after the initiation of the NHI program. However, cancer incidence rates of nasopharynx of both genders slightly decreased throughout the entire period and incidence of stomach cancer of both genders and cervical cancer of females declined beginning in 1995. For childhood cancers, the major types of leukemia, lymphomas, central nervous system neoplasms and other epithelial neoplasms for males and females accounted for nearly 55% of all types. This study presents for the first time the secular changes and age patterns in the incidence of childhood cancer using national cancer data.

The role of hepatitis B and C viruses in hepatocellular carcinoma in a hepatitis B endemic area. A case‐control study

To investigate the role of hepatitis B (HBV) and C viruses (HCV) in hepatocellular carcinoma (HCC) in an HBV endemic area and elucidate the interaction of these two viruses, a case‐control study of 128 patients with HCC and 384 age‐matched and sex‐matched control subjects was done. The positive rates of hepatitis B surface antigen (HBsAg, 77.3%, 99 of 128) and anti‐HCV (19.5%, 25 of 128) in patients with HCC were significantly higher than in control subjects (P < 0.001). Both HBsAg and anti‐HCV were important risk factors for HCC (relative risks, 13.96 and 27.12, respectively), and the risk for HCC was elevated significantly to 40.05 (95% confidence interval, 12.57 to 127.6) when HBsAg and anti‐HCV were considered simultaneously. These results suggested that HBV and HCV were associated highly with HCC in an HBV endemic area and that these two viruses might contribute independent but synergistic effects to the pathogenesis of HCC.

Thirty-Year Outcomes of the National Hepatitis B Immunization Program in Taiwan

Thirty-Year Outcomes of the National Hepatitis B Immunization Program in Taiwan Hepatitis B virus (HBV) infection causes infant fulminant hepatitis (IFH), and chronic HBV infection may progress to chronic liver disease (CLD) and hepatocellular carcinoma (HCC). Taiwan launched a nationwide HBV immunization program for newborns in July 1984,1 which has successfully lowered the prevalence of chronic HBV carriers, incidence of HCC, and mortality of IFH in vaccinated birth cohorts.2-4 The mortality of CLD before and after HBV immunization has never been examined. We assessed the 30-year outcomes of the immunization program.

Quality assessment and improvement of nationwide cancer registration system in Taiwan: a review

Cancer registration provides core information for cancer surveillance and control. The population-based Taiwan Cancer Registry was implemented in 1979. After the Cancer Control Act was promulgated in 2003, the completeness (97%) and data quality of cancer registry database has achieved at an excellent level. Hospitals with 50 or more beds, which provide outpatient and hospitalized cancer care, are recruited to report 20 items of information on all newly diagnosed cancers to the central registry office (called short-form database). The Taiwan Cancer Registry is organized and funded by the Ministry of Health and Welfare. The National Taiwan University has been contracted to operate the registry and organized an advisory board to standardize definitions of terminology, coding and procedures of the registrys reporting system since 1996. To monitor the cancer care patterns and evaluate the cancer treatment outcomes, central cancer registry has been reformed since 2002 to include detail items of the stage at diagnosis and the first course of treatment (called long-form database). There are 80 hospitals, which count for >90% of total cancer cases, involved in the long-form registration. The Taiwan Cancer Registry has run smoothly for >30 years, which provides essential foundation for academic research and cancer control policy in Taiwan.

Independent Effect of EBV and Cigarette Smoking on Nasopharyngeal Carcinoma: A 20-Year Follow-Up Study on 9,622 Males without Family History in Taiwan

This study aimed to assess independent effects of EBV and cigarette smoking on nasopharyngeal carcinoma, which have never been assessed in long-term follow-up studies. A cohort of 9,622 men was enrolled from 1984 to 1986. Blood samples collected at study entry were tested for antibodies against EBV antigens (anti-EBV) viral capsid antigen immunoglobulin A and DNase. The cigarette smoking habit was inquired through questionnaire interview. Newly developed nasopharyngeal carcinoma cases were ascertained through computerized linkage with national cancer registry profile. Coxs proportional hazard regression analysis was used to estimate multivariate-adjusted hazard ratio with its 95% confidence interval (95% CI). During the follow-up of 173,706 person-years, 32 pathologically confirmed nasopharyngeal carcinoma cases were identified >1 year after recruitment. Increasing serum levels of anti–EBV viral capsid antigen immunoglobulin A and DNase were significantly associated with nasopharyngeal carcinoma risk in a dose-response relationship. The multivariate-adjusted hazard ratio (95% CI) of developing nasopharyngeal carcinoma for low and high antibody levels compared with seronegatives was 9.5 (2.2-40.1) and 21.4 (2.8-161.7), respectively, for anti–EBV viral capsid antigen immunoglobulin A (P < 0.001 for trend), and 1.6 (0.5-4.6) and 16.0 (5.4-47.1), respectively, for anti–EBV DNase (P < 0.001 for trend). The shorter the time interval between study entry and nasopharyngeal carcinoma diagnosis, the higher was the proportion of anti–EBV viral capsid antigen immunoglobulin A among nasopharyngeal carcinoma patients. The multivariate-adjusted hazard ratio (95% CI) was 3.0 (1.3-7.2) for ≥30 pack-years of cumulative cigarette smoking compared with <30 pack-years as the reference. The longer and heavier the cigarette smoking habit, the higher was the nasopharyngeal carcinoma risk. Anti–EBV viral capsid antigen immunoglobulin A, anti–EBV DNase, and long-term heavy cigarette smoking are independent nasopharyngeal carcinoma risk predictors. (Cancer Epidemiol Biomarkers Prev 2009;18(4):1218–26)