PROGNOSTIC ROLE OF POSITRON EMISSION TOMOGRAPHY AND COMPUTED TOMOGRAPHY PARAMETERS IN STAGE I LUNG ADENOCARCINOMA

Abstract

Objectives: According to the current pathological classification, lung adenocarcinoma includes histological subtypes with significantly different prognoses, which may require specific surgical approaches. The aim of the study was to assess the role of CT and PET parameters in stratifying patients with stage I adenocarcinoma according to prognosis.

Methods: Fifty-eight patients with pathological stage I lung adenocarcinoma who underwent surgical treatment were retrospectively reviewed. Adenocarcinoma in situ and minimally-invasive adenocarcinoma were grouped as non-invasive adenocarcinoma (NIA). Other histotypes were referred as invasive adenocarcinoma (IA). CT scan assessed parameters were: ground glass opacity (GGO) ratio, tumor disappearance rate (TDR) and consolidation diameter (CD). The prognostic role of the following PET parameters was also assessed: standardized uptake value (SUV) max, SUV index (SUV max to liver SUV ratio), metabolic tumor volume (MTV), total lesion glycolysis (TLG).

Results: Seven patients had a NIA and 51 an IA. Five-year disease-free survival and cancer-specific survival for NIA and IA were respectively 100% and 100%, 70% and 91%. Univariate analysis showed a significant difference in SUV max, SUV index, GGO ratio and TDR ratio values between NIA and IA groups. Optimal SUV max, SUV index, GGO ratio and TDR cut-off ratios to predict invasive tumors were respectively 2.6, 0.9, 40% and 56%. TLG, SUV max, SUV index significantly correlated with cancer specific survival.

Conclusions:  CT and PET scan parameters may differentiate between non-invasive and invasive stage I adenocarcinomas. If these data are confirmed in larger series, surgical strategy may be selected on the basis of preoperative imaging.