SUV(max) reduction predicts long-term survival in patients of non-pCR both in the tumor and lymph nodes after neoadjuvant chemoradiotherapy in esophageal squamous cell carcinoma

BACKGROUND: A pathological complete response (pCR) after neoadjuvant chemoradiotherapy (NACRT) ensures long-term survival in esophageal squamous cell carcinoma (ESCC) patients following esophagectomy, but pCR patients are a minority. The aim here was to identify prognostic factors in patients with non-pCR ESCC after NACRT. METHODS: This is a retrospective study. Investigated were 5-year overall survival (OS), disease-specific survival (DSS), and relapse-free survival (RFS) among non-pCR ESCC patients divided into pT0N0, primary site pCR (pT0N+), lymph node pCR (pT+N0), and non-pCR in both the tumor and lymph node (pT+N+) subgroups after NACRT and esophagectomy. Focusing on the SUV(max) reduction rate in the primary tumor in 88 patients who underwent FDG-PET before and after NACRT, we used univariate and multivariate Cox proportional hazard models to identify prognostic factors. RESULTS: Although there were no significant survival differences among non-pCR ESCC patients with pT0N+, pT+N0, or pT+N+, survival rate among pT+N+patients was the poorest. After setting a 60% cutoff for the SUV(max) reduction rate in the tumor, RFS curves for non-pCR patients significantly differed between patients above the cutoff and those below it. For pT+N+ patients, the SUV(max) reduction rate (<60% vs ≥ 60%) was an independent prognostic factor of OS, DSS, and RFS. CONCLUSION: Because ESCC patients with SUV(max) reduction rates of <60% in the tumor after NACRT and categorized as pT+N+ after NACRT had significantly poorer prognoses, even after esophagectomy, a change in treatment strategy may be an option to improve survival.