1263MO - The impact of PET-CT and brain MRI for metastasis detection among patients with T1-stage lung cancer: Findings from a large cohort study

Background

18F-fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (PET-CT) and brain magnetic resonance imaging (MRI) are commonly used to detect metastases in lung cancer patients. However, current guidelines for the use of these methods in T1-stage lung cancer are not risk-based and need to be optimized.

Methods

T1-stage lung cancer patients who underwent pathologic examination and PET-CT plus MRI were included from January 2009 through July 2022, and their clinical-pathological and survival information was collected. The proportion of metastasis was observed in tumors with different sizes (5-30 mm) stratified by radiologic types (solid and sub-solid nodules). Additionally, a cohort of T1-stage patients who received routine CT only (or plus MRI) was set as control. The overall survival (OS) was compared between patients with and without PET-CT examination.

Results

A total of 2,298 patients receiving PET-CT were included, of which 686 (29.9%) had metastases (44.3% among the solid nodules and 23.4% among the sub-solid nodules). The proportion of metastases increased with the size, no metastasis occurred in patients with solid nodules <8mm and sub-solid nodules <10mm. Moreover, metastasis occurred in only 5% of patients with solid nodules <10mm and sub-solid nodules <13mm. Among patients without baseline metastasis, those who underwent PET-CT (n=1,691) had longer OS compared to that who received CT only (or plus MRI, n=2,581) (HR, 0.72; 95%CI, 0.52-0.99; P=0.045), while such benefits were observed among solid nodules≥10mm (HR, 0.28; 95%CI, 0.14-0.56; P<0.001) and sub-solid nodules≥13mm (HR, 0.67; 95%CI, 0.46-0.99; P=0.046). Table: 1263MO

Univariable Cox proportional hazards model analyses of overall survival in different sub-groups patients

Conclusions

PET-CT and MRI might not benefit T1-stage lung cancer patients with solid nodules <10mm and sub-solid nodules <13mm, considering their low metastatic potency. These examinations remained recommended for T1-stage lung cancer patients with solid nodules ≥10mm and sub-solid nodules ≥13mm.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.