A propensity score-matched analysis to evaluate the benefit of adjuvant therapy on disease recurrence of esophageal squamous cell carcinoma after R0 esophagectomy

Abstract

Background: Esophageal squamous cell carcinoma (ESCC) is common in China and has a poor prognosis despite radical surgery. Guidelines around the use of adjuvant therapy (AT) in ESCC are indecisive. We assessed the benefit of AT on recurrence-free survival (RFS) in Chinese patients with ESCC using propensity score (PS) matching.

Methods: This retrospective cohort study used hospital electronic medical records (EMRs) of 523 adults diagnosed between 2013 to 2019 with pathologically confirmed ESCC after R0 esophagectomy without neoadjuvant therapy. PSs were calculated using a generalized linear regression model based on demographic, clinical, and pathologic features. Patients with and without AT were matched using nearest neighbor method and caliper value 0.05. Subgroup analyses were stratified by PS.

Results: Younger patients with more advanced/poorly differentiated disease were more likely to receive AT (P<0.05). There were 137 matched pairs in the AT/No AT groups. After matching, the AT group tended to have longer median RFS [95% confidence interval (CI): 2.21 years (1.54-3.20)] than the No AT group [1.75 years (1.37-2.21)] (P=0.18). The benefit was significant in patients with PS ≥0.40 [hazard ratio 0.55, 95% CI: 0.32-0.87, median RFS (95% CI): 2.22 years (1.30-3.52) versus 1.23 years (0.90-1.64), P=0.03]. In other PS subgroups, median RFS was similar in AT and No AT groups.

Conclusions: After adjusting for baseline characteristics, AT tended to improve RFS after R0 esophagectomy in Chinese patients, with significant benefit associated with a higher PS score. The utility of PS to guide patient selection for AT in clinical practice needs further investigation.

Keywords: Esophageal cancer; propensity score matching (PS matching); recurrence-free survival (RFS); squamous cell carcinoma; survival.

Figure 1

Patient selection. SCC, squamous cell carcinoma; AT, adjuvant therapy.

Figure 2

Kaplan-Meier curves (log-rank tests) for recurrence-free survival in patients who did/did not receive adjuvant therapy. (A) Before matching. (B) After matching.

Figure 3

Kaplan-Meier curves (log-rank tests) for recurrence-free survival in patients who did/did not receive adjuvant therapy by PS stratum. (A) PS <0.20. (B) 0.20≤ PS <0.30. (C) 0.30≤ PS <0.40. (D) PS ≥0.40. PS, propensity score.