Re-evaluating the Role of Adjuvant Chemotherapy after Neoadjuvant Therapy in Resected Gastric Cancer.

Background

Perioperative chemotherapy is standard of care for resectable gastric cancer (GC), but many patients do not complete adjuvant chemotherapy (AC). It remains unclear whether AC following neoadjuvant chemotherapy (NAC) improves survival. We sought to assess differences in survival between patients with resectable GC who did vs. did not receive AC after NAC and surgery.

Methods

A retrospective study was conducted at a tertiary cancer center to evaluate survival differences in patients who did vs. did not receive AC. Patients with resected GC who received NAC were included.

Results

Of 339 patients, 264 (78%) received AC. There were no significant differences in median event-free survival (EFS) (7.0 vs. 7.5 years, p = 0.089) or overall survival (OS) (10 vs. 7.8 years, p = 0.11) between AC and non-AC groups. In the node-negative (ypN-) cohort (n = 169), there was no association between AC receipt and EFS (12 vs. 10 years, p = 0.7) or OS (12 vs. 10 years, p = 0.5). In the node-positive (ypN+) cohort (n = 170), AC receipt was associated with longer EFS (4.8 vs. 2.7 years, p = 0.031) but not OS (5.5 vs. 2.8 years, p = 0.071). High-risk patients based on lymph node ratio (LNR>0.0685; n = 112) who received AC (n = 87; 78%) had longer EFS (p = 0.014) and OS (p = 0.033). Finally, AC receipt was associated with longer EFS (p = 0.014) and OS (p = 0.024) in those with incomplete/poor response to NAC (Becker tumor regression grade [TRG] 2-3).

Conclusions

AC following NAC was not associated with improved survival in resected ypN- GC. High LNR identified a ypN+ subgroup in which AC receipt was associated with longer EFS and OS. In patients with incomplete/poor response to NAC (TRG 2-3), AC receipt was associated with longer EFS and OS.