Close Association of IASLC/ATS/ERS Lung Adenocarcinoma Subtypes with Glucose-uptake in Positron Emission Tomography

Objectives: Correlations between maximum standardized uptake value (SUVmax) in fluorodeoxyglucose positron emission tomography (FDG-PET) and IASLC/ATS/ERS histopathologic subtypes of lung adenocarcinoma remain unclear. Therefore, the aim of this study was to retrospectively clarify associations between SUVmax and adenocarcinoma subtypes with postoperative outcomes.

Materials And Methods: Associations of SUVmax measured in preoperative FDG-PET/CT and histologic subtypes of lung adenocarcinoma resected in our hospital were analyzed retrospectively. Overall and disease-free survival rates after surgery were calculated by the Kaplan-Meier method, and survival differences between patient groups were tested by the log-rank test. Multivariate analysis for survival was performed using the Cox regression model.

Results: A total of 255 patients (130 men and 125 women; mean age, 69 years; range, 22-88 years) were included in the study. Clinical stages included IA in 151 patients, IB in 79, IIA in 9, IIB in 10, and IIIA in 6. SUVmax was closely associated with histologic subtype in resected specimens (p<0.0001). Values were highest in micropapillary predominant invasive adenocarcinoma (MPA) followed by solid predominant (SPA), invasive mucinous (IMA), acinar predominant (APA), papillary predominant (PPA), lepidic predominant (LPA), minimally invasive adenocarcinoma (MIA), and adenocarcinoma in situ (AIS). When the subtypes were classified into three subgroups [group A, AIS+MIA+LPA (low risk); group B, APA+PPA+IMA (intermediate risk); and group C, SPA+MPP (high risk)] by expected postoperative prognoses, there were significant differences in SUVmax among the subgroups corresponding to recurrence risk (p=0.0001).

Conclusion: Preoperative SUVmax was closely associated with both adenocarcinoma subtype and aggregated subgroups, reflecting malignant grade of the tumor and prognosis.