The role of adjuvant chemotherapy after neoadjuvant chemotherapy or chemoradiotherapy plus esophagectomy in patients with esophageal cancer: a retrospective cohort study

BACKGROUND: The 5-year survival rate of patients with locally advanced esophageal cancer is still low after neoadjuvant therapy plus esophagectomy, and additional adjuvant treatment may be required. Some studies have shown that patients can still benefit from adjuvant chemotherapy (AC) despite its toxic and side effects. This study was designed to explore which patients could benefit from AC. METHODS: A retrospective cohort study based on patients who received neoadjuvant therapy plus esophagectomy with complete survival information between December 2014 and November 2020 was conducted. The inclusion criteria were as follows: esophageal cancer was diagnosed by pathological biopsy; neoadjuvant chemotherapy; neoadjuvant chemoradiotherapy; R0 resection. The exclusion criteria were as follows: neoadjuvant chemotherapy combined with targeted therapy or immunotherapy; adjuvant radiotherapy, adjuvant chemoradiotherapy, immunotherapy, or targeted therapy; dead within 90 days of surgery; nonradical (R1/R2) resection; one cycle of postoperative chemotherapy. Patients were divided into AC group (AC) and non-AC group [AC(−)] according to whether AC was performed. We obtained the tumor recurrence and survival status of the patients through inpatient medical records, outpatient electronic medical records, and telephone follow-up of the First Affiliated Hospital of Zhengzhou University. Overall survival (OS) and recurrence-free survival (RFS) were investigated as the outcome measures via Kaplan-Meier curves and Cox analyses. RESULTS: In total, 318 patients were enrolled, among which 214 patients received AC while the other 104 patients did not [AC(−)]. There were significant differences in age and lymph nodes dissected between patients who received AC and those who did not receive AC (P<0.05). Survival curves were plotted using the Kaplan-Meier method, and in the overall group and subgroup, AC was beneficial for OS but not for RFS. In the overall group, sex (P=0.027) and age (P=0.027) were independent prognostic factors for OS. Subgroup multivariate Cox proportional hazards analysis showed that age (P=0.026) and AC (P=0.023) were independent prognostic factors for patients. CONCLUSIONS: For patients with locally advanced esophageal cancer who have residual disease after surgery, adjuvant therapy after neoadjuvant chemoradiotherapy and surgery may be a better treatment.