Chemoradiotherapy and Subsequent Immunochemotherapy as Conversion Therapy in Unresectable Locally Advanced Esophageal Squamous Cell Carcinoma: A Phase II NEXUS-1 Trial.

PURPOSE

This phase II trial investigated the safety and efficacy of chemoradiotherapy (CRT) followed by immunochemotherapy (iCT) and surgery in unresectable locally advanced esophageal squamous cell carcinoma (ESCC).

PATIENTS AND METHODS

Patients with unresectable locally advanced ESCC received radiotherapy (50 Gy/25f, 5 days/week) and nab-paclitaxel (100 mg on day 1/week) plus cisplatin (25 mg/m2 on day 1/week) for 5 weeks, followed by tislelizumab (200 mg on day 1/cycle) plus chemotherapy (nab-paclitaxel 150 mg/m2 and cisplatin 75 mg/m2 on day 2/cycle) for two 21-day cycles. Patients who converted to resectable underwent surgery 2 to 4 weeks afterward. The primary endpoint was a 1-year progression-free survival (PFS) rate.

RESULTS

Thirty patients were enrolled and underwent CRT (median follow-up: 21 months), of whom 24 received iCT. Twenty (66.7%) patients achieved resectability (R0: 95.2%; pathologic complete response: 65.0%; major pathologic response: 90.0%). One-year PFS and overall survival (OS) rates were 79.4% and 89.6%, respectively. The R0 resection group exhibited longer PFS (median, not reached vs. 8.4 months; HR = 0.28; 95% confidence interval, 0.08-0.84; P = 0.02) and OS (median, not reached vs. 19.2 months; HR = 0.18; 95% confidence interval, 0.04-0.73; P < 0.01) than the nonsurgery group. Grade 3 to 4 adverse events were observed in 11 (11/30, 36.7%) patients, and immune-related pneumonitis was observed in 5 (5/24, 20.8%) patients. Post-CRT minimal residual disease before surgery was associated with unfavorable PFS and OS.

CONCLUSIONS

Our study met the primary endpoint. Conversion CRT and subsequent iCT followed by surgery was a promising treatment strategy for unresectable locally advanced ESCC.