Two versus three to four cycles of neoadjuvant immunochemotherapy for locally advanced esophageal squamous cell carcinoma in real-world practice

Background: There is currently no consensus on whether intensive cycles of neoadjuvant immunochemotherapy provide greater benefit than do less intensive cycles (two cycles) in esophageal cancer (EC). Therefore, in this study, we assessed the efficacy and safety of three to four cycles of neoadjuvant immunochemotherapy compared to two cycles for treating patients with locally advanced esophageal squamous cell carcinoma (ESCC). Methods: This is a retrospective study of patients enrolled on previous clinical studies involving locally/ regionally advanced ESCC (St. II-IVA) who received preoperative immunochemotherapy at the Department of Thoracic Surgery, the First Affiliated Hospital, Zhejiang University School of Medicine from 2019 to 2021. In this study, patients were planned to receive 2-4 cycles of chemoimmunotherapy. In this secondary analysis, patients who received three to four cycles of neoadjuvant immunochemotherapy were compared to those receiving two cycles in terms of safety and oncologic outcomes. The follow-up duration required for inclusion was at least one year following surgery, or until the patient died or independently elected to cease treatment if less than one year. Results: Our study identified a total of 142 participants, who were categorized into two groups based on the number of neoadjuvant treatment cycles: the two cycles group (2 cycles) (n=65) and the three to four cycles group (3-4 cycles) (n=77). Regarding the rate of major pathologic response (MPR), the rates for the 3-4 cycles and 2 cycles groups were 22.1% and 20.0%, respectively, although this difference was not statistically significant (P=0.25). Similarly, the rate of pathologic complete remission (pCR) was higher in the 3-4 cycles group at 14.3% compared to 7.7% in the 2 cycles group, but the difference did not reach statistical significance (P=0.07). However, the incidence of adverse events (AEs) classified as grade 3 or 4 was significantly higher in the 3-4 cycles group than in the 2 cycles group (36.4% vs. 18.5%; P=0.02). The median disease-free survival (DFS) for the 3-4 cycles group was 30.8 months [95% confidence interval (CI): not reached to not reached] and was not reached in the 2 cycles group (hazard ratio 2.35, 95% CI: 1.134-4.86; P=0.02). The 2 cycles group did not reach the median overall survival (OS) (hazard ratio 2.47, 95% CI: 1.08- 5.53; P=0.045), with that in the 3-4 cycles group 34.9 months (95% CI: 24.5 to not reached). Interestingly, the survival outcomes were more favorable in the 2 cycles group for certain subgroups of patients: those who were male, those with a history of smoking, those with a history of drinking, and those who did not achieve MPR. Conclusions: Two cycles of neoadjuvant immunochemotherapy can be considered in locally advanced ESCC at high risk of developing toxicity with 3-4 cycles with similar oncologic outcomes.