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.
Highlights
Colorectal cancer (CRC) is the third most common cancer and one of the major causes of cancer-associated mortality worldwide [1]
We screened the medical records of patients who underwent preoperative 18F-FDG positron emission tomography/computed tomography (PET/CT) followed by curative operations for CRC at our institution between January 2015 and April 2021
The excellent inter-observer and intra-observer agreement was found in SUVmax and SUVpeak with interclass correlation coefficient (ICC) values ranging from 0.999 to1.000
Summary
Colorectal cancer (CRC) is the third most common cancer and one of the major causes of cancer-associated mortality worldwide [1]. Multiple treatments for primary and metastatic CRC have emerged, which includes curative surgery, radiotherapy, neoadjuvant chemotherapy, and immunotherapy [2]. The strong heterogeneity of CRC often leads to different prognosis and clinical outcome in patients who received similar treatment [5]. Microsatellite instability (MSI), caused by the absence of one or more MMR genes, has been considered as a reliable biomarker in the prediction of treatment response and prognosis in patients with CRC. MSI was identified as an important indicator in the selection of chemotherapy drugs of CRC [8]. A noninvasive method is urgently needed to preoperatively evaluate the MSI status and better facilitate the immunotherapy of CRC patients. Microsatellite 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. Purpose: To investigate whether the metabolic parameters derived from18Ffluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) can predict MSI status in patients with CRC
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
