FDG PET-CT imaging for pre operative staging in patients with colorectal cancer

Abstract Background Cetuximab and Panitumumab,serve as monoclonal antibodies against the epidermal growth factor receptor (EGFR), have been used in the treatment of metastatic colorectal cancer. However, mutations in KRAS, NRAS, BRAF indicate a lack of response to treatment for EGFR. The identification of KRAS/NRAS/BRAF mutation status is important to improve the success rate of this therapy. PET/CT imaging is a biomolecular imaging technique that can supply various information about malignant tumors. Hence, we investigated whether KRAS/NRAS/BRAF mutation status is related to 18F-FDG uptake heterogeneity in liver metastases of colorectal cancer, and whether 18F-FDG PET / CT imaging can predict the status of KRAS / NRAS / BRAF mutation and guide treatment of liver metastases of colorectal cancer in this study. Methods 60 patients with liver metastases of colorectal cancer (lmCRC) were analysed retrospectively who had received 18F-FDG PET / CT before surgical operation. Heterogeneity index (HI) was defined by divided SUVmax by SUVmean. HI were assessed for patient (-P), colorectal cancer (-T) and liver metastatic lesions (-L). Results HI-L was significantly higher in NRAS/ KRAS/BRAF mutation group than in NRAS/ KRAS/BRAF wild-type group (2.48 ± 0.69 and 2.05 ± 0.31, respectively; p = 0.01). The groups of the number of liver metastatic sites were significantly different (p = 0.02). In multivariate analysis, HI-L was only significantly associated with KRAS/NRAS/BRAF mutation status (p = 0.008). Using a HI-L cut-off of 2.12, the sensitivity and specificity of predicting KRAS/NRAS/BRAF mutation were 72.7% and 70.4%, respectively. Conclusions Higher HI-L is associated with elevated NRAS/KRAS/BRAF mutation status in patients with lmCRC. 18F-FDG PET/CT can be used to predict the KRAS/NRAS/BRAF mutation status of lmCRC and to select the optimal therapeutic strategy.

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Does Routine Triple-Time-Point FDG PET/CT Imaging Improve the Detection of Liver Metastases?

Diagnostics ◽

10.3390/diagnostics10090609 ◽

2020 ◽

Vol 10 (9) ◽

pp. 609

Author(s):

Yu-An Yen ◽

Wen-Sheng Huang ◽

Chuang-Hsin Chiu ◽

Yu-Chang Tyan ◽

Jhi-Joung Wang ◽

...

Keyword(s):

Colorectal Cancer ◽

Liver Metastases ◽

Fdg Pet ◽

Ct Imaging ◽

Liver Lesions ◽

Delayed Imaging ◽

Pet Ct ◽

Initial Imaging ◽

Fdg Pet Ct ◽

Time Point

Prior reports have demonstrated the improved ability of delayed fluorine-18 (18F) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging (dual-time-point imaging) in detecting more patients with liver metastases. To evaluate whether routine triple-time-point FDG PET/CT imaging improves the detection of liver metastasis not visualized on initial imaging. To our knowledge, no triple-time-point imaging has been reported. This retrospective study included total 310 patients with various malignancies who underwent PET/CT scans. Triple-time-point imaging including the liver was obtained. The comparison between negative and positive liver lesions on delayed imaging for patients with initial negative imaging were analyzed. Of the 310 patients, 286 did not exhibit liver lesions on initial imaging, but six of the 286 patients exhibited lesions on delayed imaging. No additional liver lesions were detected on further delayed imaging in the 286 patients. The other 24 patients with liver lesions identified on initial imaging still showed lesions on delayed and further delayed imaging. The analysis showed a significant difference in the percentage of colorectal cancer (66.7%) and liver lesions before the PET scan (50.0%) compared with unchanged results (22.1% and 3.9%, respectively). Routine triple-time-point imaging did not improve the detection of liver metastases; however, it may be recommended in patients with colorectal cancer and liver lesions before the PET scan.

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