[An evaluation of tumor markers and risk factors in mass screening for various cancers]

The borderline values of tumor markers and the clarification of risk factors for cancer are problems to be solved in the development of mass screening tests for various cancers. A tiny abnormality may be overlooked in an evaluation based upon traditional reference standards obtained by surveying healthy subjects. Both negative and positive values are required in mass screening for various cancers. That is, cut-off values should minimize the incidence of false negatives and false positives in the screening test. A modified combination assay using tumor markers and risk factors was used to screen 967 healthy subjects over age 50 for nonspecific cancers and the results were analyzed. Positive rates based on ordinary cut-off values for each tumor marker were about 6 to 7% in CEA, CA19-9 and BFP, 2.7% in SPAN-1, 1.3% in PAP, and less than 1% in AFP, SCC, CA125 and NCC -ST-439. For pepsinogen, a risk factor of various cancers especially in the digestive tract, the cut-off value was determined as the mean-SD in 967 healthy subjects over 50 years old. That is, the cut-of value for pepsinogen I was 18.7 ng/ml. A lower value was found in 149 subjects (15.4%). The cut-off value for pepsinogen II was 7.4 ng/ml and a lower value was found in 227 subjects (23.5%). The cut-off value for the pepsinogen I/II ratio was 1.2 and 108 subjects showed lower values (11.2%). Positive cases were referred to specialists in various fields to detect the specific suspected cancer.(ABSTRACT TRUNCATED AT 250 WORDS)