[Clinical preventive medicine in cancer diagnosis--proposal for a new cancer diagnostic system in an aging society].

To enroll a large percentage of the cancer high-risk group and to simultaneously screen for various kinds of cancer, a modified combination assay of tumor markers and risk factors in serum was devised. A pilot study using 5 tumor markers, AFP, CEA, CA19-9, CA125, Dupan-2, as well as 3 risk factors of pepsinogen, PGI, PGII, PGI/II, showed 87.0% sensitivity and 58.8% specificity in 54 patients with various cancers and 163 healthy subjects. Eighty percent of stage I or II cases were detected except for one stage I case of right lung cancer and one stage II case of oral cavity cancer. Field work is now under way to detect various cancers among approximately 1000 inhabitants above 50 years of age in a particular town using 11 tumor markers and 3 risk factors. One hundred fifty three of 967 cases (male 372, female 595) showed various abnormal values and some were examined further as higher risk cases to detect particular cancers suspected from the results of the modified combination assay. At present, 5 PAP positive cases were referred to urological clinic for examination and 3 were confirmed histologically as prostatic cancer. This corresponds to approximately a 0.8% of detection rate which is more than 40 times the prostatic cancer mortality. Other kinds of cancer are still under investigation at various specified clinics. If cancer is not detected in these higher risk cases, they will be followed year to year. Further, the most suspicious cases will be examined at a chromosome or DNA level.(ABSTRACT TRUNCATED AT 250 WORDS)