Abstract:
Objective To investigate the clinical value of 18F-fluorodeoxyglucose (FDG) PET/CT imaging in preoperative tumor, node, metastasis (TNM) staging of rectal cancer and the correlation between the maximum standardized uptake value (SUVmax) of primary lesions and clinicopathological features.
Methods To evaluate the accuracy of 18F-FDG PET/CT in assessing invasion depth, lymph node metastasis, metastasis, and clinical staging before operation, a retrospective analysis was performed on data collected from 117 rectal cancer patients, including 66 males and 51 females (aged 29–83 years old, median age 57 years), who underwent 18F-FDG PET/CT examination before operation in Fujian Cancer Hospital from January 2013 to December 2018. Kappa test was used for consistency test. The patients were grouped according to gender, age, length of primary lesion, pathological type, differentiated degree, lymphovascular invasion (LVI), perineural invasion (PNI), TNM staging, and clinical staging. Independent sample t-test and one-way ANOVA were used to analyze the difference in SUVmax between groups. Pearson or Spearman correlation was used to analyze the relationship between the SUVmax of primary lesions and clinicopathological features.
Results The diagnostic accuracies of 18F-FDG PET/CT on rectal cancer invasion depth, lymph node metastasis, metastasis, and clinical staging were 76.1%, 81.2%, 95.7%, and 76.9%. The consistency with pathological results was as follows (κ=0.601, 0.535, 0.867, 0.667, all P<0.01). Statistically significant differences were observed in the SUVmax of different groups of length of primary lesion (t=4.982, P<0.01), LVI (t=−2.581, P=0.011), PNI (t=−2.873, P=0.005), N staging (t=2.792, P=0.006), and clinical staging (F=3.072, P=0.031), but no statistically significant differences were observed in the SUVmax of different groups of gender (t=0.688, P=0.493), age (t=1.523, P=0.130), pathological type (t=0.886, P=0.377), differentiated degree (t=0.045, P=0.964), T staging (F=2.323, P=0.103), and M staging (t=−1.502, P=0.136). The SUVmax of the primary lesion was positively correlated with the length of the primary lesion, LVI, PNI, N staging, and clinical staging (r=0.230–0.308, all P<0.05).
Conclusions 18F-FDG PET/CT has high accuracy in diagnosing rectal cancer primary lesions, lymph nodes, and metastasis and is an effective method for staging rectal cancer. The SUVmax of primary lesions can partially reflect the invasion and proliferation ability of rectal cancer.