Association of KRAS Mutation in Non Small Cell Lung Cancer and 18F-FDG Uptake in PET/CT
Tania Labiano, Carlos Caicedo, Maria J Garcia-Velloso, Luis M Seijo, Alfonso Gurpide, Jose Luis Perez-Gracia, Maria D Lozano. University Clinic of Navarra, Pamplona, Spain
Background: Non small cell lung cancer (NSCLC) tumors with KRAS mutations display primary resistance to EGFR TKIs, molecular evaluation of KRAS is important to predict clinical treatment outcomes and to decide treatment. Imaging studies such as CT scan and Positron emission tomography (PET) scan have been used in lung cancer for an accurate initial staging, response monitoring, and follow – up. Many factors can influence FDG uptake behaviour and the underlying mechanisms for FDG accumulation in tumours are still unknown. Mutation of the KRAS gene is one of the most important events in carcinogenesis of the lung. The objective of this study is to determine differences in 18F-FDG uptake between patients with NSCLC who harbor KRAS mutation.
Design: We include 55 patients (39 M, 16 F, median age 61) with diagnosis of NSCLC by cytologic procedure (Bronchoscopy, EBUS and CT guided FNA). They also underwent PET-CT for staging performed by a PET-CT Biograph LSO-DUO scanner (SIEMENSTM).KRAS mutations in codons 12 and 13 in exon 2 were analyzed using conventional DNA sequencing using ABI PRISM TM 310XL.
Results: KRAS mutations were identified in 24 patients (17 M, 7 F, median age 61). All of them were smokers. Regard histologic subtype 18 (75%) of them were adenocarcinoma, 5 (20.8%) squamous cell carcinoma and 1 cases (4.2%) NSCLC- NOS. Patients with wild type and mutated KRAS had the same age, gender and histologic subtype distribution. [18F] FDG uptake was higher in patients with KRAS mutated than wild-type in primary tumour (SUVmax 11.5 ± 6.7 vs 8.3 ± 3.8) (p 0.03) and nodal metastases (SUVmax 9.15 ± 6 vs, 6.19 ± 3.1) (p0.04) Distant metastases were observed in 33 patients and the SUVmax was higher in mutant KRAS cases than wild-type but without statistically significant differences.
Conclusions: Among patients with advanced lung cancer, those smokers, men and with higher SUVmax on primary tumour and nodal metastases in 18F-FDG PET/CT are more likely to carry KRAS mutations. 18F-FDG uptake might be helpful to discriminate patients who harbor KRAS mutations with poorer prognosis.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 293, Monday Morning