Countermeasure and opportunistic screening systems for oral cancer

•Reported Countermeasure and Opportunistic screening systems for oral cancer.•Checked 19,721 persons in Countermeasure Screening over 27 years.•Checked 29,912 persons in Opportunistic Screening over 13 years.•Detection of oral cancer, 0.13, 0.08% in countermeasure, opportunistic screening.•Screening Systems is useful for detecting oral cancer and mucosal disease. Tokyo Dental College started oral cancer screening in cooperation with a local dental association in 1992. Reveal the usefulness of Countermeasure and Opportunistic Screening Systems for Oral Cancer. The actual results of countermeasure and opportunistic oral cancer screening systems are reported. Countermeasure screening for the public was performed in each region, and opportunistic screening was performed in a general dental clinic of a cooperating physician. In countermeasure screening, 19,721 persons were checked from 1992 to 2018; the gender ratio was 1:3. The close examination rate was 4.45%. The detection rates of oral cancer and oral potentially malignant disorders were 0.13% and 1.85%, respectively. In opportunistic screening, 29,912 persons were checked from 2006 to 2018; the gender ratio was 2:3. The close examination rate was 2.33%. The detection rates of oral cancer and oral potentially malignant disorders were 0.08% and 2.15%, respectively. The close examination rate was significantly lower in opportunistic screening than in countermeasure screening. The oral cancer detection rates and the positive predictive value for cancer were equivalent. In addition, the detection rate of oral potentially malignant disorders was significantly higher in opportunistic screening than in countermeasure screening. Oral cancer detection rates were equivalent between countermeasure and opportunistic screenings, and opportunistic screening were more effective on number of participants and the close examination rate, and the detection rate of oral potentially malignant disorders.