Predictive Value of Metabolic Parameters Derived From 18F-FDG PET/CT for Microsatellite Instability in Patients With Colorectal Carcinoma

Abstract

BackgroundMicrosatellite instability (MSI) is one of the important factors that determine the effectiveness of immunotherapy in colorectal cancer (CRC) and serves as a prognostic biomarker for its clinical outcomes.PurposeTo investigate whether the metabolic parameters derived from18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) can predict MSI status in patients with CRC.Materials and MethodsA retrospective analysis was performed on CRC patients who underwent 18F-FDG PET/CT examination before surgery between January 2015 and April 2021. The metabolic 18F-FDG PET/CT parameters of the primary CRC lesion were calculated and recorded with different thresholds, including the maximum, peak, and mean standardized uptake value (SUVmax, SUVpeak, and SUVmean), as well as the metabolic tumor volume (MTV) and the total lesion glycolysis (TLG). The status of MSI was determined by immunohistochemical assessment. The difference of quantitative parameters between MSI and microsatellite stability (MSS) groups was assessed, and the receiver operating characteristic (ROC) analyses with area under ROC curves (AUC) was used to evaluate the predictive performance of metabolic parameters.ResultsA total of 44 patients (24 men and 20 women; mean ± standard deviation age: 71.1 ± 14.2 years) were included. There were 14 patients in the MSI group while there were 30 in the MSS group. MTV30%, MTV40%, MTV50%, and MTV60%, as well as TLG50% and TLG60% showed significant difference between two groups (all p-values <0.05), among which MTV50% demonstrated the highest performance in the prediction of MSI, with an AUC of 0.805 [95% confidence interval (CI): 0.657–0.909], a sensitivity of 92.9% (95% CI: 0.661–0.998), and a specificity of 66.7% (95% CI: 0.472–0.827). Patients’ age and MTV50% were significant predictive indicators of MSI in multivariate logistic regression.ConclusionThe metabolic parameters derived from18F-FDG PET/CT were able to preoperatively predict the MSI status in CRC, with MTV50% demonstrating the highest predictive performance. PET/CT imaging could serve as a noninvasive tool in the guidance of immunotherapy and individualized treatment in CRC patients.

Metabolic activity via 18F-FDG PET/CT is predictive of microsatellite instability status in colorectal cancer

“…This is different from a recent study of Chung and colleagues [18] in gastric cancer, exhibiting that MSI-H tumors caused higher SUV max on 18 F-FDG PET/CT imaging, that may because gastric cancer with MSI-H tended to be larger-sized and histologically heterogeneous, which was different from colorectal cancer. We found a positive relationship between MSI status and MTV in colorectal cancer, which was in agreement with the previous findings [32]. Liu et al [32] retrospectively analyzed the pretreatment parameters of PET and reported the highest diagnostic performance of MTV in predicting MSI status in CRC despite its small sample size of 50 patients.…”

“…We found a positive relationship between MSI status and MTV in colorectal cancer, which was in agreement with the previous findings [32]. Liu et al [32] retrospectively analyzed the pretreatment parameters of PET and reported the highest diagnostic performance of MTV in predicting MSI status in CRC despite its small sample size of 50 patients. However, the specific Fig.…”

Added value of quantitative, multiparametric 18F-FDG PET/MRI in the locoregional staging of rectal cancer

“…However, an independent confirmatory study in a different, prospective, patient cohort would be required before any clinical recommendation can be made. MTV also demonstrated an association with overall survival, indicating potential prognostic value, as has been proposed in previous studies [35]. This might contribute to the diagnostic value of volumetric PET parameters in the future.…”

Correlations among KRAS Mutation, Microsatellite Instability, and 18F-FDG Uptake in Colon Cancer

“…Furthermore, ICIs showed clinical benefit only in patients with MSI (Le et al, 2015, André et al, 2020. Only two studies have reported the relationship between SUVmax and MSI in colon cancer, and these included a small number of patients with MSI, which showed no significant relationship between SUVmax and MSI (Li et al, 2021;Liu et al, 2021). In this study, the SUVmax of tumors with MSI was significantly higher than that of tumors with MSS.…”

“…The correlation between SUVmax and KRAS mutations has been assessed in several studies. However, these studies showed conflicting results and included a relatively small number of patients (Kawada et al, 2012;Chen et al, 2014;Krikelis et al, 2014;Kawada et al, 2015;Lee et al, 2016;Cho et al, 2017;Oner et al, 2017;Kim et al, 2019;Arslan et al, 2020) On the other hand, only two studies have reported the relationship between SUVmax and MSI in colon cancer, and these studies found no significant relationship between SUVmax and MSI (Li et al, 2021;Liu et al, 2021).…”