Revision of lymph node classification in the Japanese Classification of Esophageal Cancer and its impact on definitive chemoradiotherapy for stage IV esophageal cancer: a single-institution retrospective study.

The 2022 revision of the Japanese Classification of Esophageal Cancer reclassified certain lymph node metastases previously considered locoregional as distant lymph node metastasis. Consequently, some patients previously diagnosed with stage IVA or III disease and treated with definitive chemoradiotherapy (dCRT) are now categorized as stage IVB disease with distant lymph node metastasis (IVB-Lym). We retrospectively evaluated the outcomes of dCRT in patients initially diagnosed with stage IVA or III disease and subsequently reclassified under the revised system. Among patients with esophageal cancer who underwent dCRT between January 2017 and December 2020 at our institution, 65 were reclassified as stage IVA (n = 19) or stage IVB-Lym (n = 46). Best overall response, overall survival (OS), progression-free survival (PFS) and chemotherapy-related adverse events (AEs) were evaluated. Complete or partial response was achieved in 84.2% of patients with stage IVA and 84.4% of those with stage IVB-Lym. The median OS and PFS were 26 and 8 months, respectively, in the stage IVA group and 35 and 9 months, respectively, in the stage IVB-Lym group. No significant differences were observed in OS (P = 0.69) or PFS (P = 0.67) between the two groups. The incidence and severity of AEs were generally comparable. No significant differences in efficacy or toxicity were observed between patients with reclassified stage IVB-Lym and those with stage IVA disease. These findings suggest that dCRT may be considered a treatment option for carefully selected patients with stage IVB-Lym following comprehensive clinical evaluation.