What is the prognostic value by the combination of morphological and metabolic data in lung cancer patients? A complementary study of CT and PET/CT

Objectives. The purpose of this study was to determine the influence both of CT features and of metabolic parameters by FDG PET/CT on overall survival (OS) in patients (pts) with lung cancer. Methods and Materials. Between 2008 and 2010, we reviewed CT and PET/CT images of 83 pts (mean age 71 years, range 50‐83) with lung cancer. The period between two imaging modalities ranged between one and two months. Chest CT findings of nodules documented were location, pleural effusion, extra nodules, margins, density, lung parenchima, bronchogram, thincking pleural, escavation and lymph nodes. Both qualitative and semiquantitative data (SUVmax) were recovered by FDG PET/CT. The correlations among CT, PET/CT and OS were obtained using Kaplan Meier survival analysis. Results. 71 pts had a NSCLC (55 adenocarcinoma, 14 squamous cell carcinoma and 2 LCLC) and 12 had a SCLC. The majority of pts were at stage IV (n=42; 50.6%), 22 at stage III, 6 at stage II and 4 at stage I. 52 pts had a history of smoking. At CT imaging the location of nodules was 36 in left superior lobe, 3 in middle lobe, 6 in left inferior lobe, 28 in right superior lobe, 9 in right inferior lobe and 8 multiple site. 16 pts had pleural effusion, controlateral nodules and broncogram. The margins of nodules were irregular in 39 pts, regular in 3, spiculated in 16 and lobulated in 25. The nodules were solid in 70 pts , excavated in 6 pts and with thincking pleural in 10 pts. Lymph nodes were detected in 41% of entire population. At PET/CT, median SUVmax of primary tumour (n=83) was 11 (range:3.41‐39.31), of lymph node (n=53) was 8.87(range 3‐26.92), and of distant metastases (n=32) was 7.95 (range 3.20‐44). After a follow up period of 20.3±17.6 months, 17 pts were alive and 66 dead. Age, stage, nodule density, broncogram, escavation and lymph nodes at CT were significantly different between alive and dead pts (chi‐square test, all p<0.05), being higher in the second group. At Kaplan Meier analysis, the association of lymph nodes at CT and median SUVmax of primary tumour was predictive of OS (log rank, p<0.05). Conclusions. CT features of aggressive lung disease are correlated with a worse prognosis. The association of positive lymph nodes at CT and high SUVmax of primary tumour by PET are predictive of poor OS.