Clinical T categorization in stage IA lung adenocarcinomas: prognostic implications of CT display window settings for solid portion measurement
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Our study aimed at evaluating the prognostic implications of lung and mediastinal CT display window settings for solid portion measurements on the eighth-edition lung cancer staging system’s clinical T (cT) categorization.
We retrospectively analyzed 691 surgically treated patients from 2009 to 2015 for clinical stage IA lung adenocarcinomas. Solid portions were measured at the lung and mediastinal window settings, respectively, and cT categories were determined for each measurement (cTlung and cTmediastinum). The prognostic power of the two cT factors for disease-free survival (DFS) was assessed using Cox regression, and concordance indices (C-indices) were compared using the Student t test. Subsequently, the patients were split into training and validation cohorts to calculate optimal cutoffs for the cT categorization of mediastinal window–based solid portions (cToptimal) and validate its prognostic performance.
Both cTlung ((cT1b: adjusted HR, 3.547; p = 0.017), (cT1c: adjusted HR, 9.439; p < 0.001)) and cTmediastinum ((cT1b: adjusted HR, 4.635; p < 0.001), (cT1c: adjusted HR, 11.235; p < 0.001)) were significantly associated with DFS for each multivariable Cox model. The C-indices were 0.772 (95% CI, 0.702–0.842) for cTlung and 0.787 (95% CI, 0.726–0.848) for cTmediastinum (p = 0.789). The optimal cutoffs for cT categorization of the mediastinal window–based solid portions were 0.9 cm and 1.8 cm. However, there were no significant differences in the C-indices among cTlung, cTmediastinum, and cToptimal (p > 0.05).
The prognostic performances of the cT categorizations at the lung and mediastinal windows were not significantly different. The current cT categorization based on the lung window measurement is appropriate as it stands.
• Discriminatory power of the eighth-edition clinical T category was not significantly affected by the CT display window settings.
• Given the facts that the lung window setting enables more sensitive detection of the solid portions and higher correlation with the pathological invasive components, our findings may support adherence to the usage of the lung window setting for the solid portion measurement per the current recommendations.
KeywordsNon–small cell lung carcinoma Adenocarcinoma Multidetector computed tomography Neoplasm staging Disease-free survival
Akaike’s information criterion
Clinical T categorization based on solid portion measurement with the lung window setting using the eighth-edition T coding system
Clinical T categorization based on solid portion measurement with the mediastinal window setting using the eighth-edition T coding system
Clinical T categorization for the mediastinal window–based solid portion using optimal cutoffs
Electronic medical record
Tumor disappearance ratio
We sincerely express our gratitude to Myunghee Lee and Ju Young Jeong for their help in data acquisition.
This study was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT & Future Planning (grant number: 2017R1A2B4008517).
Compliance with ethical standards
The scientific guarantor of this publication is Chang Min Park.
Conflict of interest
The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Written informed consent was waived by the Institutional Review Board.
Institutional Review Board approval was obtained.
Study subjects or cohorts overlap
Some study subjects or cohorts have been previously reported in a journal article (Kim et al; in press).
• diagnostic or prognostic study
• performed at one institution
- 8.Travis WD, Asamura H, Bankier AA et al (2016) The IASLC lung cancer staging project: proposals for coding T categories for subsolid nodules and assessment of tumor size in part-solid tumors in the forthcoming eighth edition of the TNM classification of lung cancer. J Thorac Oncol 11:1204–1223CrossRefGoogle Scholar
- 14.Kim H, Goo JM, Kim YT, Park CM (2019) Clinical T category of non-small cell lung cancers: prognostic performance of unidimensional versus bidimensional measurements at CT. Radiology. https://doi.org/10.1148/radiol.2019182068:182068