Prognostic Value of FDG-PET/CT Parameters in Patients with Locally Advanced Rectal Cancer Treated with Neoadjuvant Approach

OBJECTIVETo determine the prognostic and/or predictive role of 18F-FDG PET/CT parameters, such as SUVmax, SUVmean, Metabolic Tumor Volume (MTV) and Total Lesion Glycolysis (TLG=MTVxSUVmean), for the patients with locally advanced rectal cancer (LARC) treated with neoadjuvant radiotherapy±chemotherapy.METHODSBetween January 2005 and December 2016, a total of 106 patients with clinical T3-4 and/or N+ rectal cancer without distant metastasis were included in this study. Correlation between metabolic and volumetric parameters and tumor characteristics was evaluated. Prognostic factors for overall sur-vival (OS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were analyzed.RESULTSThe median follow-up duration for all patients was 39.0 months (range, 6–103 months). Pathologic complete response (pCR) was defined as the absence of viable cancer cells in the resected specimen (ypT0N0). pCR was achieved in 17% of all cases (18/106). There was a weak correlation between SUV-max of primary tumor and MTV ([r]=0.238; p<0.001). However, SUVmax of primary tumor and TLG were significantly correlated (r=0.538; p