Differences in disease status between patients with progression after first-line chemotherapy versus early relapse after adjuvant chemotherapy who undergo second-line chemotherapy for gastric cancer: Exploratory analysis of the randomized phase III TRICS trial.

BACKGROUND

Second-line chemotherapy (SLC) improves survival in advanced gastric cancer (AGC). Patients receiving SLC are categorized into two disease status groups: tumour progression after first-line chemotherapy and early recurrence after adjuvant chemotherapy. Differences between these groups have not yet been clarified.

PATIENTS AND METHODS

A total of 163 eligible patients registered in the randomized phase III TRICS trial evaluating SLC for patients with AGC was classified into the progressive disease (PD) group (n = 55) or the early relapse (ER) group (n = 108). We compared overall survival (OS), progression-free survival (PFS), overall response rate (ORR), and safety. Adjusted OS and adjusted PFS were estimated using inverse probability of treatment weighting (IPTW).

RESULTS

The ER group had a lower median age than the PD group (66 vs. 72 years; P = 0.016), performance status (PS) 0 was more frequently seen in the ER group (87% vs. 71%; P = 0.012). The adjusted median OS was 13.7 months in the ER group and 13.6 months in the PD group (IPTW hazard ratio [HR]: 1.023; P = 0.854). The adjusted median PFS was 4.9 months in the ER group and 4.4 months in the PD group (IPTW HR: 0.707; P = 0.004). ORR was significantly better in the ER group than the PD group (21.3% vs. 4.9%; P = 0.020). No significant differences were observed in the incidence of adverse events.

CONCLUSIONS

ER was associated with improved PFS and better ORR than PD, although no difference in survival was demonstrated. From the viewpoint of treatment outcome, it seems appropriate to treat patients with ER in the same way as patients with PD.

CLINICAL TRIAL REGISTRATION

UMIN 000002571.