Pembrolizumab combined with paclitaxel and platinum as induction therapy for locally advanced esophageal squamous cell carcinoma: a retrospective, single-center, three-arm study.

Background: Pembrolizumab has been shown to have a powerful benefit for locally advanced or metastatic esophageal cancer. The aim of present study was to evaluate the efficacy and safety of pembrolizumab combined with neoadjuvant chemotherapy for locally advanced and potentially resectable esophageal squamous cell carcinoma (ESCC). Methods: Patients diagnosed with clinical stage III-IV ESCC and have a chance of resectability at Fujian Provincial Hospital were included into this study. Patients received pembrolizumab in combination with paclitaxel and nedaplatin as induction therapy once every 3 weeks in the first stage. After 4 cycles of pembrolizumab therapy, the patients then chose to undergo radical surgery (group A), radical radiotherapy (group B), or neither (group C). In the third stage, maintenance treatment with pembrolizumab was administered to all patients. Results: A total of 39 patients (33 male and 6 female) with a median age of 64 years were included. After immune response evaluation in the first stage, 34 (87.2%) patients achieved immune partial response (iPR), and 5 (12.8%) patients achieved immune stable disease (iSD). The objective response rate (ORR) was 87.2% (34/39), and the disease control rate (DCR) was 100%. In the second stage, 22 patients received radical surgery, all of whom achieved R0 resection. The major pathological response (MPR) rate was 68.2% (15/22), and the pathological complete response (pCR) rate was 45.5% (10/22). Of the patients, 9 chose radiotherapy as the radical therapeutic method and 8 chose not to undergo any radical therapy. The median period of pembrolizumab therapy was 8 cycles (4-22 cycles). The median follow-up time was 14 months (3-34 months). The median overall survival and progression-free survival (PFS) times were not reached. The incidence of severe adverse events (AEs) (grade ≥3) was 15.4% (6/39). Conclusions: Pembrolizumab combined with paclitaxel and platinum for locally advanced and potentially resectable ESCC has a high ORR, high surgical conversion, MPR, pCR, and R0 resection rates, and tolerable AEs. Also, pembrolizumab could provide good benefits in sequential treatment with radical radiotherapy or maintenance therapy.