Annual Lung Cancer Screening By Chest X-Ray Results In Higher Profits For The Exclusion Of Lung Cancer.

e23050 Background: Chest X ray (CXR) has been the most common screen procedure for detection of lung cancer. However, if patients had old inflammatory shadows such as tuberculosis, calcification and fibrotic changes, it would become increasingly difficult to detect the lung cancer. In that case, the previous CXR helps the detection of new shadows. We examine whether the repeat participants (pts) who received the medical checkup annually, may improve the rate of lung cancer detection. Methods: Our clinic “MedCity21” was a university outpatient clinic to undergo a complete medical checkup in private health screening program. The pts with abnormalities detected in CXR were announced by call request and invited to our specialty clinic for chest CT scan as further examination. We examined the varieties of abnormal shadows by CXR and CT scans in recent 3 years. Furthermore, we compared the differences between the repeat and the first-time pts using the chi-square tests. Results: In 2016, 2017 and 2018, a total of 10020, 11925 and 12540 pts were enrolled, respectively. The CXR abnormalities for further examinations were detected in 282 (2.8%), 344 (2.9%) and 335 (2.6%) pts, respectively. After the call requests, 203 (72.0%), 239 (69.4%) and 239 (71.3%) pts received chest CT scan in our clinic. In 2016 and 2017, 7 and 9 pts were diagnosed as lung cancer within 12 months follow-up. In 2018, 6 pts were diagnosed as lung cancer, and another 4 pts were now observed. The numbers of lung cancer detections by CXR per 100,000 people were 70.0, 75.5 and ≥47.8, respectively. The repeat / first time pts in 2018 were 6898/5642 pts (55/45%), and 142/193 pts (2.1/3.4%) had CXR abnormalities (p < 0.01), respectively. The varieties of abnormal shadows by CT scans showed that 8.3/20.8% of old inflammatory shadows (p < 0.01), 11.9/20.7% of nodule or GGO (p = 0.47), 12.8/12.3% of Mycobacterial infections or suspected (p = 0.46), and 11.0/6.9% of acute bacterial infections (p = 0.98). Lung cancer was detected in 3/3 pts (p = 0.86), respectively. Conclusions: The repeat pts had significantly lower rate of CXR abnormalities detection, and the first time pts had higher rate of error detection old inflammatory changes as significant. In private health screening program, the repeat pts may have higher profits for the exclusion of lung cancer than the first time pts.