Accuracy of Detecting Residual Disease After Neoadjuvant Chemoradiotherapy for Esophageal Squamous Cell Carcinoma: the preSINO Trial (Pre-Surgery If Needed for Oesophageal Cancer)

Neoadjuvant chemoradiotherapy (nCRT) followed by esophagectomy is a standard treatment for locally-advanced esophageal cancer. After nCRT, high pathologically complete response (pCR) rates are being achieved in patients with esophageal cancer, especially squamous cell carcinoma (SCC). Surgery for esophageal cancer is risky and is associated with reduced quality of life. It is important to know that with an accurate and safe clinical evaluation strategy, some patients might delay surgery or avoid unnecessary surgery and be safely monitored instead. Therefore, an active surveillance strategy has been proposed for patients with clinically complete response (cCR) after nCRT.

The previous European preSANO trial (Lancet Oncol. 2018 Jul;19(7):965-974, PMID: 29861116) showed that the clinical response evaluations (CRE) were sufficiently accurate to detect residual tumor after nCRT in patients with mainly adenocarcinoma, however, its applicability to SCC, which is characterized by extensive lymph node metastasis, remains unknown.

The objective of this study is to assess the accuracy of response evaluations after nCRT based on the preSANO trial, including positron emission tomography with computed tomography (PET-CT), endoscopic bite-on-bite biopsies and endoscopic ultrasonography (EUS) with fine-needle aspiration (FNA) in patients with potentially operable esophageal SCC. Additionally, this study also explores the value of circulating-tumor DNA (ctDNA) in predicting residual disease.

Locally-advanced operable esophageal SCC patients who are planned to undergo nCRT according to the CROSS regimen and are planned to undergo surgery will be recruited from three high-volume Asian centers. Four to six weeks after completion of nCRT, patients will undergo a first clinical response evaluation (CRE-1) consisting of endoscopic bite-on-bite biopsies. In patients without histological evidence of residual tumor (i.e. without positive biopsies), surgery will be postponed another six weeks. A second clinical response evaluation (CRE-2) will be performed 10-12 weeks after completion of nCRT, consisting of PET-CT, endoscopic bite-on-bite biopsies and EUS with FNA. After CRE-2, all patients without evidence of distant metastases will undergo esophagectomy. Primary endpoint is the accuracy of CRE for detecting TRG3-4 or TRG1-2 with ypN+ residual tumor with a prespecified false-negative rate of 19.5%.

Secondary endpoint includes the accuracy of detecting any residual tumor. Exploratory analyses of ctDNA will be performed in patients with available blood samples.