Relationship between KRAS mutations and dual time point 18F-FDG PET/CT imaging in colorectal liver metastases

Abstract

Purpose: To investigate the association between metabolic parameters of dual time point ¹⁸F-FDG PET/CT imaging and Kirsten rat sarcoma (KRAS) mutation status in colorectal liver metastases (CRLM).

Methods: Forty-nine colorectal cancer patients with 87 liver metastatic lesions were included in this retrospective study. KRAS gene mutation tests were also performed for all the patients. The maximum standardized uptake value (SUV_max) was measured for each hepatic metastatic lesion on both early and delayed scans, and the change of SUV_max (ΔSUV_max) and retention index (RI) were calculated. Uni-variate and multi-variate analyses were employed to determine the relationship between any PET/CT parameters and KRAS mutation status.

Results: Thirty-seven (42.5%) liver metastatic lesions harboring KRAS mutations were identified. The SUV_max of CRLM with KRAS mutation both on early and delayed scans was significantly higher than those with wild-type KRAS (10.7 ± 6.0 vs. 7.8 ± 3.3, P = 0.002; 15.5 ± 10.1 vs. 10.0 ± 4.2, P < 0.001, respectively). Compared with wild-type KRAS CRLM, ΔSUV_max and RI (%) of CRLM with KRAS mutation were also significantly higher than those with wild-type KRAS (4.8 ± 4.7 vs. 2.2 ± 2.0, P < 0.001; 45.3 ± 28.2 vs. 29.6 ± 24.7, P = 0.003, respectively). Multi-variate analyses showed that the SUV_max on both early and delayed scans, ΔSUV_max, and RI (%) were the 4 independent factors to predict CRLM patients harboring KRAS mutations.

Conclusion: The SUV_max on both early and delayed scans, ΔSUV_max, and RI (%) may be the 4 independent factors to predict CRLM patients harboring KRAS mutations.

Keywords: 18F-FDG PET/CT; Colorectal cancer; Dual time-point imaging; KRAS; Liver metastasis.