Purpose: The objective of this study was to correlate the association between mutated KRAS and wild-type colorectal cancer (CRC) by using various 18F-FDG PET–related parameters.
Methods: One hundred twenty-one CRC patients who had undergone preoperative PET/CT were included in this study. Several PET/CT-related parameters, including SUVmax and various thresholds of metabolic tumor volume, total lesion glycolysis, and PET/CT-based tumor width, were measured. Tumor- and PET/CT-related parameters were correlated with genomic expression between KRAS mutant and wild-type groups, using a Mann-Whitney U test and logistic regression analysis.
Results: Colorectal cancer tumors with a mutated KRAS exhibited higher SUVmax and an increased accumulation of FDG among several threshold methods. Multivariate analysis showed that SUVmax and using a 40% threshold level for maximal uptake of TW (TW40%) were the 2 predictors of KRAS mutations. The odds ratio was 1.23 for SUVmax (P = 0.02; 95% confidence interval, 1.01–1.52) and 1.15 for TW40% (P = 0.02; 95% confidence interval, 1.02–1.30). The accuracy of SUVmax for predicting mutated KRAS was higher in patients with colon or sigmoid colon cancers, whereas it was TW40% in those with rectal cancers.
Conclusions: SUVmax and TW40% were associated in CRC with KRAS mutations. PET/CT parameters can supplement genomic analysis to determine KRAS expression in CRC.
From the *Department of Radiation Oncology, China Medical University Hospital; and †Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University, Taichung; ‡School of Medicine, Taipei Medical University, Taipei; and §Departments of Surgery and ∥Department of Nuclear Medicine and PET Center, China Medical University Hospital; ¶Department of Biomedical Imaging and Radiological Science, China Medical University; and **Cancer Center, China Medical University Hospital, Taichung, Taiwan.
Received for publication December 2, 2013; revision accepted April 2, 2014.
Conception and design: S.-W.C., H.-C.C., W.T.-L.C., C.-H.K.; administrative support: T.-C.H., K.-Y.Y., T.-W.C., C.S.-F.; collection and assembly of data: all authors; data analysis and interpretation: S.-W.C., C.-H.K.; manuscript writing: all authors; final approval of manuscript: all authors.
Conflicts of interest and sources of funding: The authors received study grants for projects DMR-102-023 and DMR-103-018 conducted in their hospital, issued by the Taiwan Ministry of Health and Welfare Clinical Trial and Research Center for Excellence (DOH102-TD-B-111-004) and Taiwan Ministry of Health and Welfare Cancer Research Center for Excellence (MOHW103-TD-B-111-03).
Reprints: Chia-Hung Kao, MD, Department of Nuclear Medicine and PET Center, China Medical University Hospital, No. 2, Yur-Der Rd, Taichung 404, Taiwan. E-mail: firstname.lastname@example.org.
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