The relationship between quantitative positron emission tomography parameters, the invasive lung adenocarcinoma grading system of International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society, and survival

Abstract

BACKGROUND: The impact of newly defined subtypes and grades of adenocarcinoma on the survivaland their reflection on imaging methods and nuclear medicine practices are popular research topics.AIMS: The aim of the study is to investigate quantitative positron emission tomography (PET)parameters and the adenocarcinoma grading system of the International Association for the Studyof Lung Cancer, American Thoracic Society, and European Respiratory Society in terms of survivaland potential prognosis prediction value in operated lung adenocarcinoma patients.STUDY DESIGN: One hundred and seventy‑nine patients who were surgically treated foradenocarcinoma of the lung were included in the study. 2‑deoxy‑2‑(18F) fluoro‑D‑glucose (FDG)PET/computerized tomography (CT) was applied for initial staging.MATERIALS AND METHODS: For quantitative evaluation, maximum standardized uptakevalues (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primarytumors were calculated.RESULTS: There was a statistically significant relation between grade and radiological appearance, buttumor grade and SUVmax, TLG, and MTV parameters showed no significant correlation. Pathologicaltumor size and PET/CT had strong correlation (P < 0.001, r = 0.816). There was no relationshipbetween mortality and tumor grade (P = 0.980). SUVmax, MTV, and TLG were more predictive for survival than disease grade (P = 0.022, 0.044, and 0.012, respectively). Survival differences were observed according tothe cutoff values for TLG (49.66) and MTV (9.68) (P < 0.05). Vascular invasion and central settlement were related to lymphnode involvement (P < 0.001). When the tumor/lymphadenopathy SUVmax ratio was