Correlation between KRAS mutation and18F-FDG uptake in stage IV colorectal cancer.
The purpose of this study is to evaluate the correlation between KRAS mutation,18F-FDG uptake, and metastatic pattern in advanced stage colorectal cancer (CRC) patients.



Medical records of stage IV CRC patients who underwent18F-FDG PET/CT for staging and KRAS mutation analysis were selected. On PET scans, a volume of interest (VOI) was drawn on the primary lesion.18F-FDG indices (SUVmax, SUVmean, MTV, TLG) of the primary lesions were obtained and correlated with KRAS mutation of the primary lesion. Also, metastatic sites were recorded. Association between metastatic pattern and KRAS expression and FDG indices were analyzed.



KRAS mutation was positive in 40 (43%) patients. Evaluation of FDG indices showed that higher SUVmax (14.0 vs. 11.2, p = 0.004), higher SUVmean (5.3 vs. 4.7, p = 0.005), and higher TLG (301.4 vs. 205.5, p = 0.023) were predictive of KRAS mutation compared to wild-type (WT) KRAS. Lung metastasis was more frequently involved in patients with KRAS mutation (50.0% vs. 22.6%, p = 0.006), and liver metastasis was more frequently involved in patients with WT KRAS (81.1% vs. 55.0%, p = 0.007). Multivariate analysis showed that  primary tumor location (OR 3.92, p = 0.07) and KRAS mutation (OR 2.45, p = 0.09) were significant factors in lung metastasis model.



KRAS mutation patients had more frequent lung metastasis and had higher18F-FDG uptake compared to WT KRAS in stage IV CRC.
Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Arthur
A
Cho
Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Kwanhyeong
K
Jo
Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Sang Hyun
SH
Hwang
Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Narae
N
Lee
Division of Medical Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Republic of Korea.
Minkyu
M
Jung
Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Mijin
M
Yun
Department of Nuclear Medicine, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, 22 Gwanpyeong-ro 170 beon-gil, Dongan-Gu, Anyang, 14068, Republic of Korea. hshwang@hallym.or.kr.
Hee Sung
0000-0002-2803-0282
HS
Hwang
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000235:genetics* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000556:secondary; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D000072078:Positron Emission Tomography Computed Tomography; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*; D011857:Radiographic Image Interpretation, Computer-Assisted; D019275:Radiopharmaceuticals
C117307:KRAS protein, human; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D016283:Proto-Oncogene Proteins p21(ras)
18F-FDG PET/CT; KRAS; Metastatic colorectal cancer