The Impact of Primary Tumor and Locoregional Metastatic Lymph Node SUV max on Predicting Survival in Patients with Rectal Cancer.

Objectives: The aim of this study was to evaluate the impact of maximum standard uptake value (SUV _max ) of the primary tumor and locoregional metastatic lymph node in predicting survival in patients with the preoperative rectal adenocarcinoma.
Methods: One hundred and fifteen patients [mean age ± standard deviation (SD): 58.7±11.4 years] with biopsy-proven rectal adenocarcinoma underwent ¹⁸ F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imaging for the staging were included in this study. All patients were followed-up for a minimum of 12 months (mean ± SD: 29.7±13.5 months). Tumor-node-metastasis 2017 clinical staging, SUV _max of the primary rectal tumor and locoregional lymph nodes on the PET/CT studies were evaluated.
Results: All patients had increased FDG activity of the primary tumor. The mean ± SD SUV _max of the primary tumor and locoregional metastatic lymph node were 21.0±9.1 and 4.6±2.8, respectively. Primary tumor SUV _max did not have an effect on predicting survival (p=0.525) however locoregional metastatic lymph node SUV _max had an effect (p<0.05) on predicting survival. Clinical stage of the disease was a factor predicting survival (p<0.001).
Conclusion: ¹⁸ F-FDG PET/CT is an effective imaging modality for detecting primary tumors and metastases in rectal adenocarcinoma and clinical stage assessment with PET/CT had an effect on predicting survival. Furthermore, in our study locoregional lymph node SUV _max was defined as a factor in predicting survival.