Interim Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography to Predict Pathologic Response to Preoperative Chemoradiotherapy and Prognosis in Patients With Locally Advanced Rectal Cancer.
The goal of the present study was to investigate the predictive and prognostic values of interim fluorine-18 (18F) fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) parameters for the prediction of a complete pathologic response (pCR) in patients with locally advanced rectal cancer (LARC) who had received preoperative chemoradiotherapy (PCRT).



A total 103 patients with LARC were included in the present study. All the patients were evaluated by 18F FDG PET/CT before and after 45 Gy of radiotherapy with concurrent oral capecitabine chemotherapy. The quantitative, volumetric parameters and their percentage of change (Δ%) were used to predict the pCR and calculate the overall survival (OS). The predictive value for a pCR of 18F FDG PET/CT cutoff values were determined by receiver operating characteristic analysis. The prognostic significance was assessed using Kaplan-Meier analysis.



A pCR occurred in 22 patients (21.4%). Univariate and multivariate analyses demonstrated that the post-PCRT maximum standardized uptake value (SUVmax2) and change in the SUVmax(ΔSUVmax) as significant factors for the prediction of pCR, with a sensitivity of 68.2% and specificity of 87.7% and sensitivity of 90.9% and specificity of 80.3%, respectively. Kaplan-Meier analysis showed that a low SUVmax2(< 2.5) and high ΔSUVmax(≥ 62.2%) were potent predictors for OS.



The present study has shown the capability of interim 18F FDG PET/CT parameters to predict the achievement of pCR after PCRT in patients with LARC. Of the parameters, SUVmax2and ΔSUVmaxwere potent predictors for pCR and well associated with OS.
Department of Radiology, University of Colorado School of Medicine, Aurora, CO.
Phillip J
PJ
Koo
Department of Nuclear Medicine, Pusan National University Hospital, Busan, Korea; Biomedical Research Institute, Pusan National University Hospital, Busan, Korea. Electronic address: growthkim@pusan.ac.kr.
Seong-Jang
SJ
Kim
Department of Radiology, University of Colorado School of Medicine, Aurora, CO.
Samuel
S
Chang
Department of Radiology, University of Colorado School of Medicine, Aurora, CO.
Jennifer J
JJ
Kwak
D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000401:mortality; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D059186:Chemoradiotherapy, Adjuvant / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D000072078:Positron Emission Tomography Computed Tomography; D011379:Prognosis; D012372:ROC Curve; D011868:Radioisotopes; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000401:mortality; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
D011868:Radioisotopes; D019788:Fluorodeoxyglucose F18
FDG; LARC; PCRT; PET/CT; Prognosis