Diagnostic accuracy of immunochemical faecal occult blood test for gastric cancer.

OBJECTIVES

To investigate the accuracy of the immunochemical occult blood test in screening for gastric cancer and to evaluate whether or not the upper digestive tract should be examined when the occult blood test is positive but there is no abnormal sign in the colorectum.

METHODS

In a case-control study an occult blood test was carried out on 150 subjects with gastric cancer, 150 subjects with colorectal cancer, and on 300 healthy subjects. Data were analysed from 44,996 persons attending a population screening programme who underwent both radiological gastric cancer screening (barium meal) and colorectal cancer examination by occult blood test.

RESULTS

In the case-control study the occult blood test was positive in 27/150 (18%) subjects with gastric cancer, in 112/ 150 (75%) subjects with colorectal cancer, and in 24/300 (8%) healthy controls. In the population screening programme the occult blood test was positive in 4/50 (8%) persons with gastric cancer and 3232/ 44,950 (7%) persons without gastric cancer, indicating no difference between them.

CONCLUSIONS

These data show that the immunochemical faecal occult blood test is worthless as a screening test for gastric cancer, and that examination of the upper digestive tract is unnecessary in cases where the faecal occult blood test is positive but there is no sign of colorectal disease.