***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: Three randomised clinical trials were included in this review. All of them had a high risk of bias. One trial was conducted in Shanghai, China. There are several published reports on this trial, in which data were presented differently. According to the 2004 trial report, participants were randomised to screening every six months with alpha-foetoprotein and ultrasonography (n = 9373) versus no screening (n = 9443). We could not draw any definite conclusions from it. A second trial was conducted in Toronto, Canada. In this trial, there were 1069 participants with chronic hepatitis B. The trial compared screening every six months with alpha-foetoprotein alone (n = 532) versus alpha-foetoprotein and ultrasound (n = 538) over a period of five years. This trial was designed as a pilot trial; the small number of participants and the rare events did not allow an effective comparison between the two modes of screening that were studied. The remaining trial, conducted in Taiwan and published as an abstract, was designed as a cluster randomised trial to determine the optimal interval for screening using alpha foetoprotein and ultrasound. Screening intervals of four months and 12 months were compared in the two groups. Further details about the screening strategy were not available. The trial reported on cumulative four-year survival, cumulative three-year incidence of hepatocellular carcinoma, and mean tumour size. The cumulative four-year survival was not significantly different between the two screening intervals. The incidence of hepatocellular cancer was higher in the four-monthly screening group. The included trials did not report on adverse events. It appears that the sensitivity and specificity of the screening modes were poor, accounting for a substantial number of false-positive and false-negative screening results. There is not enough evidence to support or refute the value of alpha-foetoprotein or ultrasound screening, or both, of hepatitis B surface antigen (HBsAg) positive patients for hepatocellular carcinoma. More and better designed randomised trials are required to compare screening against no screening.
Output:

Only three trials could be included in this review. One of these trials was conducted in Shanghai, China. It compared screening twice yearly with ultrasound and alpha-foetoprotein against no screening. The trial has a high risk of systematic errors (bias) and several published reports of the trial provide different results. Another trial was conducted in Toronto, Canada. It compared screening with alpha-foetoprotein and ultrasound versus screening with alpha-foetoprotein alone. This trial had too few participants. As there were no participants who were not screened, we cannot assess whether screening is effective in reducing mortality. The remaining trial was published as an abstract only. It was designed to determine the optimal time interval for screening using alpha fetoprotein and ultrasound. The cumulative four-year survival was not significantly different between the two studied screening intervals of four months and 12 months. Thus, to date, there is insufficient evidence regarding screening for liver cancer among patients with chronic hepatitis B infection.