L-[3-¹⁸F]-α-methyltyrosine uptake by lymph node metastasis is a predictor of complete response to CRT in esophageal cancer

The amino acid positron emission tomography (PET) tracer [(18)F]-3-fluoro-alpha-methyltyrosine ((18)F-FAMT) is known to be highly specific for malignancies. We evaluated the accumulation of (18)F-FDG or (18)F-FAMT in lymph nodes (LN) prior to definitive chemoradiotherapy (CRT) for esophageal cancer. We retrospectively reviewed 30 patients with esophageal squamous cell carcinoma. All patients received definitive CRT. The relationship between the accumulation of (18)F-FDG PET or (18)F-FAMT PET in LNs prior to CRT and clinical outcomes was assessed. A correlation was observed between LNs in which most of (18)F-FAMT was accumulated and complete response (CR) rate, but was not for (18)F-FDG. Additionally, for (18)F-FAMT, the CR rate was significantly higher in the LN accumulated lesion ≤ 1 group than in the LN accumulated lesion >2 group. To predict the outcome of definitive CRT in patients with esophageal cancer, it is important to evaluate the LN status.