Esophagus or stomach? The seventh TNM classification for Siewert type II/III junctional adenocarcinoma

The aim of this study is to clarify whether TNM-EC or TNM-GC is better for classifying patients with AEG types II/III.

The patients who had AEG types II/III and received D1 or more radical lymphadenectomy were selected. The patients were staged both by seventh edition of TNM-EC and TNM-GC. The distribution of the patients, the hazard ratio (HR) of each stage, and the separation of the survival were compared.

A total of 163 patients were enrolled in this study. TNM-EC and TNM-GC classified 25 (20 and 5) and 32 (20 and 12) patients to stage I (IA and IB), 15 (4 and 11), and 33 (11 and 22) to stage II (IIA and IIB), 88 (24, 3, and 61) and 63 (14, 26, and 23) to stage III (IIIA, IIIB, and IIIC), and 35 and 35 to stage IV, respectively. The distribution of the patients was substantially deviated to stage IIIC in TNM-EC but was almost even in TNM-GC. A stepwise increase of HR was observed in TNM-GC, but not in TNM-EC. The survival curves between stages II and III were significantly separated in TNM-GC (P = 0.019), but not in TNM-EC (P = 0.204). The 5-year survival rates of stages IIIA, IIIB, and IIIC were 69.0, 100, and 38.9% in TNM-EC and were 52.0, 43.4, and 33.9% in TNM-GC, respectively.

TNM-GC is better for classifying patients with AEG types II/III than TNM-EC is. These results could impact the next TNM revision for AEG.