Outcomes of patients with esophageal squamous cell carcinoma who achieved a pathological complete response in the primary lesion by neoadjuvant treatment: a Japanese nationwide cohort study

Background Minimal data was reported regarding the characteristics, risks of lymph node metastasis, and prognostic factors in esophageal cancer patients who achieved remarkable response in the primary lesion to neoadjuvant treatment (NAT). Methods This study evaluated the nationwide data of esophageal squamous cell carcinoma (ESCC) patients who underwent surgery following NAT in Japan. Of 4484 patients, 300 (6.7%) had ypT0 following NAT and curative esophagectomy. Factors associated with lymph node metastasis and prognosis were analyzed. Results Neoadjuvant chemotherapy (NAC) and neoadjuvant chemoradiotherapy (NACRT) were administered in 260 (86.2%) and 40 (13.8%) patients, respectively. Pathologically, 72 (24.0%) had lymph node metastasis (residual nodal disease; RND), and pretherapeutic lymph node metastasis was the independent risk factor for RND (odd ratio [OR]: 3.21; 95% confidence interval [CI]: 1.44–8.20; P = 0.008). The 5-year overall and relapse-free survivals were significantly longer in patients with pathological complete response (pCR) than in those with RND (both P < 0.001). Pretherapeutic cT3 or T4a tumors (hazard ratio [HR]: 1.71; 95% CI: 1.02–2.88; P = 0.043), RND (HR: 3.30; 95% CI: 1.98–5.50; P < 0.001), and operative blood loss (Liter, HR: 1.53; 95% CI: 1.07–2.19; P = 0.021) were independent risk factors affecting relapse-free survival in multivariable analysis. Conclusions Of patients with ypT0 after NAT, 24.0% had RND, and pretherapeutic lymph node metastasis was the risk factor. In addition, pretherapeutic cT3, or T4a tumors, RND, and operative blood loss were the poor prognosticators in patients with ypT0 after NAT.