The adenocarcinoma-specific stage shift in the Anti-lung Cancer Association project: significance of repeated screening for lung cancer for more than 5 years with low-dose helical computed tomography in a high-risk cohort.

BACKGROUND: We investigated whether a stage shift occurs during long-term repeated screening for lung cancer with low-dose helical computed tomography (LDCT) in a high-risk cohort. METHODS: A total of 2120 subjects (mean age, 63 years; 87% male and 83% smokers) were continuously recruited and underwent repeated screening with LDCT from 1993 through 2004. RESULTS: Nineteen lung cancers were detected at baseline examinations (prevalence cancers), and 57 lung cancers were detected at subsequent examinations (incidence cancers). For both prevalence cancers and incidence cancers, adenocarcinoma (74% and 63%, respectively), especially invasive adenocarcinoma (42% and 23%, respectively), was the most common histological diagnosis, and stage IA was the most common pathological stage (58% and 79%, respectively). The detection rate of incidence cancers other than bronchioloalveolar carcinoma became significantly higher after 5 years of LDCT examinations (r=0.50, P=0.020). Moreover, both the percentage of cancers of stage II-IV and tumor size became significantly lower for invasive adenocarcinoma after 5 years of LDCT examinations (r=-0.77, P=0.007 and r=-0.60, P=0.029, respectively). CONCLUSIONS: Repeated screening for more than 5 years might demonstrate the efficacy of LDCT screening for lung cancer through an adenocarcinoma-specific stage shift.

Progression of focal pure ground-glass opacity detected by low-dose helical computed tomography screening for lung cancer.

OBJECTIVE: To clarify the progression of focal pure ground-glass opacity (pGGO) detected by low-dose helical computed tomography (CT) screening for lung cancer. METHODS: A total of 15,938 low-dose helical CT examinations were performed in 2052 participants in the screening project, and 1566 of them were judged to have yielded abnormal findings requiring further examination. Patients with peripheral nodules exhibiting pGGO at the time of the first thin-section CT examination and confirmed histologically by thin-section CT after follow-up of more than 6 months were enrolled in the current study. Progression was classified based on the follow-up thin-section CT findings. RESULTS: The progression of the 8 cases was classified into 3 types: increasing size (n = 5: bronchioloalveolar carcinoma [BAC]), decreasing size and the appearance of a solid component (n = 2: BAC, n = 1; adenocarcinoma with mixed subtype [Ad], n = 1), and stable size and increasing density (n = 1: BAC). In addition, the decreasing size group was further divided into 2 subtypes: a rapid-decreasing type (Ad: n = 1) and a slow-decreasing type (BAC: n = 1). The mean period between the first thin-section CT and surgery was 18 months (range: 7-38 months). All but one of the follow-up cases of lung cancer were noninvasive whereas the remaining GGO with a solid component was minimally invasive. CONCLUSIONS: The pGGOs of lung cancer nodules do not only increase in size or density, but may also decrease rapidly or slowly with the appearance of solid components. Close follow-up until the appearance of a solid component may be a valid option for the management of pGGO.

Screening for lung cancer with low-dose helical computed tomography: anti-lung cancer association project.

PURPOSE: Because efficacy of lung cancer screening using chest x-ray is controversial and insufficient, other screening modalities need to be developed. To provide data on screening performance of low-dose helical computed tomography (CT) scanning and its efficacy in terms of survival, a one-arm longitudinal screening project was conducted. PATIENTS AND METHODS: A total of 1,611 asymptomatic patients aged 40 to 79 years, 86% with smoking history, were screened by low-dose helical CT scan, chest x-ray, and 3-day pooled sputum cytology with a 6-month interval. RESULTS: At initial screening, the proportions of positive tests were 11.5%, 3.4%, and 0.8% with low-dose helical CT scan, chest x-ray, and sputum cytology, respectively. In 1,611 participants, 14 (0.87%) cases of lung cancer were detected, with 71% being stage IA disease and a mean tumor diameter of 19.8 mm. At repeated screening, the proportions of positive tests were 9.1%, 2.6%, and 0.7% with low-dose helical CT, chest x-ray, and sputum cytology, respectively. In 7,891 examinations, 22 (0.28%) cases of lung cancer were detected, with 82% being stage IA disease and a mean tumor diameter of 14.6 mm. The 5-year survival rate for screen-detected lung cancer was 76.2% and 64.9% for initial and repeated screening, respectively. CONCLUSION: Screening with low-dose helical CT has potential to improve screening efficacy in terms of reducing lung cancer mortality. An evaluation of efficacy using appropriate methods is urgently required.