Interval Metastases After Neoadjuvant Chemoradiotherapy for Patients with Locally Advanced Esophageal Cancer: A Multicenter Observational Cohort Study

Abstract

Abstract Background Despite trimodality treatment, 10% to 20% of patients with esophageal cancer experience interval metastases after surgery. Restaging may identify patients who should not proceed to surgery, as well as a subgroup with limited metastases for whom long-term disease-control can be obtained. This study aimed to determine the proportion of patients with interval metastases after neoadjuvant chemoradiotherapy (nCRT) and to evaluate treatment and survival. Methods Patients who had cT2-4aN0-3M0 esophageal cancer treated with nCRT were identified from a trial database. Metastases detected up to 14 weeks after nCRT on 18F-FDG-PET/CT or during surgery were categorized as oligometastases (≤3 lesions located in one single organ or one extra-regional lymph node station) or as non-oligometastases. The primary outcome was the proportion of patients with metastases after nCRT. The secondary outcomes were overall survival (OS) and the site and treatment of metastases. Results Between 2013 and 2021, 973 patients received nCRT, and 10.3% had interval metastases. Of 100 patients, 30 (30%) had oligometastases, located mostly in non-regional lymph nodes (33.3%) or bones (26.7%). The median OS of this group was 13.8 months (95% confidence interval [CI] 9.2–27.1 months). Of 30 patients, 12 (40%) with oligometastases underwent potentially curative treatment, with a median OS of 22.8 months (95% CI 10.4–NA). The patients with non-oligometastases underwent mostly systemic therapy or BSC and had a median OS of 9 months (95% CI 7.4–10.9 months). Conclusions Interval metastases were detected in about 10% of patients after nCRT, underscoring the importance of re-staging with 18F-FDG-PET/CT for those who proceed to surgery. A favorable survival might be accomplished for a subgroup of patients with oligometastases.