Purpose: To explore he predictive values of both the baseline SUVmax of ¹⁸F-fluorodeoxy-glucose by the primary tumor in positron emission tomography/computed tomography (PET/CT) and the lymphocyte-monocyte ratio (LMR) in peripheral blood in inoperable treated esophageal squamous cell carcinoma (ESCC) patients who received concurrent chemoradiotherapy (CCRT).
Patients and methods: Between January 2011 and December 2016, 138 newly diagnosed ESCC patients from our institution were retrospectively recruited. The optimal cut-off values for baseline SUVmax and peripheral LMR were determined by individual receiver operating characteristic curves. The predictive values of baseline SUVmax and peripheral LMR for primary tumor response were examined by chi-square and Fisher’s exact tests, as was their combined predictive value.
Results: The objective response rate (ORR) was significantly different between the high-SUVmax group and the low-SUVmax group (61.9% vs 87.8%; P=0.004), as well as between the high-LMR group and the low-LMR group (80.7% vs 52.0%; P=0.001). Furthermore, the low-SUVmax-high-LMR group achieved the best ORR (100%), which was significantly different from the ORRs of the high-SUVmax-high-LMR group (ORR: 72.1%, P=0.002), the high-SUVmax-low-LMR group (ORR: 45.7%, P=0.001), and the low-SUVmax-low-LMR group (ORR: 45.7%, P=0.001).
Conclusion: Baseline SUVmax of the primary tumor and the peripheral LMR are independent predictors of CCRT response in the primary tumors of ESCC patients. Patients who have lower FDG uptake accompanied by a higher peripheral LMR are more likely to have a better primary tumor response after CCRT.
Keywords: esophageal squamous cell carcinoma, maximum standardized uptake value, lymphocyte–monocyte ratio, chemoradiotherapy, tumor response