Author of

• 10962

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  P1.20 - Poster Session 1 - Early Detection and Screening (ID 172)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Imaging, Staging & Screening
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/28/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 10965

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    P1.20-003 - Lung Cancers Detected Using Low-dose CT Screening: Results of an Eight-year Observational Study (ID 1779)

    09:30 - 16:30  |  Author(s): G. Ishii
    • Abstract

    Background
    To evaluate lung cancers detected using low-dose CT screening between February 2004 and March 2012.

    Methods
    The number of screenees analyzed in the observational study was 12,116. Screenees were classified into three groups based on their smoking index (SI): SI ≥ 600, SI < 600, and never-smokers. Overall, 147 lung cancers in 132 cases treated at the National Cancer Center Hospital and the National Cancer Center Hospital East were evaluated according to the smoking index. Adenocarcinomas were evaluated based on the following classification: group A (adenocarcinoma in situ and minimally invasive adenocarcinoma), and group B (invasive adenocarcinoma). Statistical analyses were performed using the chi-square test.

    Results
    The ages of the patients with lung cancer ranged between 42 and 85 years (mean, 61 years). Thirty-two of the 2989 male screenees (1.48%) and 2 of the 149 female screenees (1.34%) in the SI≥600 group, 22 of the 2989 male screenees (0.74%) and 10 of the 796 female screenees (1.26%) in the SI<600 group, and 16 of the 2148 male screenees (0.74%) and 50 of the 3878 female screenees (1.29%) in the never-smoker group were diagnosed as having lung cancer. Among the 147 lung cancers, 8 lesions (5.4%) did not present as nodules and instead appeared as a partial thickening of the bulla wall, a funicular-like shadow, a pneumonia-like shadow, etc. Among the remaining 139 lung cancers, 35 lesions (25.2%) presented as pure ground-glass nodules (GGNs), 64 lesions (46%) presented as part-solid nodules, and 40 lesions (28.8%) presented as solid nodules. The histology of the lung cancers was adenocarcinoma in 132 cases (89.8%), squamous cell carcinoma in 8 cases (5.4%), small cell carcinoma in 3 cases (2%), adenosquamous carcinoma in 1 case (0.7%), carcinoid tumor in 2 cases (1.4%), and NSCLC in 1 case (0.7%). The disease stages were as follows: IA, 127 (86.4%); IB, 11 (7.5%); IIA, 2 (1.4%); IIB, 1 (0.7%); IIIA, 3 (2.0%); and IIB, 3 (2.0%). Among the 147 cancers, the number of incident cases was 8 in the SI≥600 group (median follow-up period, 3.1 years), 3 in the SI<600 group (median follow-up period, 2.9 years), and none in the never-smoker group (median follow-up period, 3.0 years). Lung cancer cases in smokers (including ex-smokers) occurred predominantly in men (male, 54; female, 12), while lung cancer cases in never-smokers occurred predominantly in women (female, 50; male, 16) (P < 0.0001). The number of adenocarcinomas in smokers (including ex-smokers) was 29 in group A and 24 in group B, while the number of adenocarcinomas in never-smokers was 42 in group A and 23 in group B (P = 0.274). In the never-smoker group, the number of adenocarcinomas in men was 7 in group A and 9 in group B, while the number of adenocarcinomas in women was 35 in group A and 14 in group B (P < 0.05).

    Conclusion
    The number of invasive adenocarcinomas was not statistically different between smokers (including ex-smokers) and never-smokers. Never-smokers should also be a target population of CT lung cancer screening. Adenocarcinoma may be overdiagnosed among female never-smokers.