Prognostic significance of adjuvant chemotherapy cycles after curative gastrectomy for gastric cancer: A propensity score-matched study

The optimal minimum number of Adjuvant Chemotherapy (AC) cycles for patients with advanced gastric cancer (GC) remains uncertain. We included 1433 patients with stage II–III GC. Overall survival (OS) was compared across groups receiving different numbers of AC cycles. Propensity score matching (PSM) and multivariable Cox regression were used to adjust for confounding. A prognostic nomogram was developed and validated, and its performance was compared with models without AC cycles and with TNM stage alone. Five-year OS was significantly lower among patients receiving 0, 1–4, or 5 cycles of AC than among those receiving 8 cycles. OS did not differ significantly between patients receiving 6, 7, or >8 cycles and those receiving 8 cycles. There was no difference in 5-year OS between patients receiving 1–4 cycles and those receiving 5 cycles. Patients were grouped as ≥6 cycles, 1–5 cycles, or 0 cycles. The ≥6-cycle group had better OS than the 1–5-cycle (p = 0.039) and 0-cycle groups (p < 0.001); the 1-5-cycle group had better OS than the 0-cycle group (p = 0.011). These findings were consistent before and after PSM. A nomogram incorporating AC cycles outperformed a nomogram without AC cycles and one using TNM stage alone. Completing at least six AC cycles is associated with optimal survival benefit in stage II–III GC. Incorporating AC cycles into the nomogram improves accuracy and precision of OS prediction.