Combined alpha fetoprotein testing and ultrasonography as a screening test for primary liver cancer

Abstract

Objective: To assess the validity and cost of a screening test for primary liver cancer using combined serum alpha fetoprotein testing and ultrasonography.

Setting: An urban community in Shanghai, China.

Methods: 9373 subjects aged 35 to 59 with positive hepatitis B surface antigen (HBsAg) or chronic hepatitis were studied. Outcome measures were detection rate, false positive rate, and positive predictive value, the cost for each primary liver cancer detected, and the average cost of detecting each additional primary liver cancer by the combined method. The number of small primary liver cancers detected was used for the economic evaluation.

Results: 20,294 screening examinations were carried out. Primary liver cancer was detected in 51 subjects, 36 of whom had small primary liver cancer. When alpha fetoprotein and ultrasonography were used in parallel the detection rate, false positive rate, and positive predictive value were 92%, 7.5%, and 3.0%, respectively; the cost for each primary liver cancer detected was 30,206 RMB (Chinese currency, $3639). When ultrasonography was used alone the detection rate, false positive rate, and positive predictive value were 84%, 2.9%, and 6.6%, respectively; the cost for each primary liver cancer detected was 16,451 RMB ($1982). When the alpha fetoprotein test was used alone the detection rate, false positive rate, and positive predictive value were 69%, 5.0%, and 3.3%, respectively; the cost for each primary liver cancer detected was 25,139 RMB ($3029).

Conclusion: The combination of both screening methods results in a relatively small increase in detection but a considerably higher false positive rate, increasing the costs. The combined test may be the best choice for primary liver cancer screening in developed areas of China, but otherwise, ultrasonography alone is the method of choice.