Wenjun Ye

M.Med.

The First Affiliated Hospital of Guangzhou Medical University

research assistant

NLST (Learn more about this study)

NLST-1280

Jul 8, 2024

Validation of Diameter Thresholds for Pure Ground-Glass Pulmonary Nodules in Low-Dose CT Lung Cancer Screening: A Comparative Study with the Chinese Large-Scale Screening Project Using NLST Cohort Data

Objective:
This project aims to validate the diameter thresholds for pure ground-glass pulmonary nodules identified in low-dose CT (LDCT) lung cancer screening. By comparing findings from the National Lung Screening Trial (NLST) cohort with those from the Guangzhou Lung-care program, a large-scale lung cancer screening project in China, the study seeks to enhance the accuracy of early lung cancer detection guidelines, achieving results in the NLST cohort consistent with the Guangzhou Lung-care program and thereby expanding the applicability and generalizability of our study.
Background:
Pure ground-glass nodules (GGNs) present diagnostic challenges due to their indeterminate nature, often requiring precise criteria for effective monitoring and intervention. Previous studies in China have suggested specific diameter thresholds for GGNs, which have shown promising results in identifying malignancies at early stages. However, these thresholds need validation in different populations to confirm their generalizability and effectiveness.
Methods:
This is a retrospective analysis of Guangzhou Lung-care program. We retrieved the average transverse diameter, location, and pathologic results (if any) of the detected pGGNs, frequency, CT reports and interval of each follow-up from the dataset. Diagnostic performances for “lung cancers” were evaluated using AUCs, sensitivities, and specificities, with diameter thresholds for pGGNs ranging from 5 to 10 mm. We set up three“lung cancers”outcomes in our study: (1) minimally invasive adenocarcinoma (MIA) & invasive adenocarcinoma (IA), (2) Atypical adenomatous hyperplasia (AAH) & Adenocarcinoma in situ (AIS) & MIA & IA and (3) IA-only.
Key Results
Raising the threshold from 5 to 7mm improved AUCs for outcome 1 (0.711 to 0.829), outcome 2(0.748 to 0.804) and outcome3 (0.783 to 0.833). However, increasing the threshold from 7 to 10mm resulted in reduced AUCs for outcome 1(0.829 to 0.767), outcome 2(0.804 to 0.744) and outcome 3(0.833 to 0.800). In outcome 1, increasing the threshold from 5 to 8mm significantly improved specificity (60.97% to 88.85%) and PPVs (5.87% to 14.88%), but decreased sensitivity (94.44% to 75.56%). Raising the threshold from 8 to 10mm further reduced sensitivity (75.56% to 60.00%), while slightly increasing specificity (88.85% to 93.47%) and PPVs (14.88% to 19.15%). No significant differences were found among three outcomes.
Conslusion: This research will bridge the gap between regional screening practices and contribute to the global effort in early lung cancer detection. By incorporating robust, validated criteria into screening protocols, healthcare providers can improve diagnostic accuracy, reduce unnecessary interventions, and ultimately, save lives.
Significance:
This study will provide crucial insights into the effectiveness of diameter thresholds for GGNs in LDCT lung cancer screening across different populations. By validating these criteria in the NLST cohort, we aim to refine screening protocols, potentially leading to earlier detection of lung cancer and improved patient outcomes globally. The comparative analysis will also highlight potential demographic and geographic variations in nodule characteristics, further informing personalized screening strategies.