Combination chemotherapy for older patients with unresectable biliary tract cancer: a prospective observational study using propensity-score matched analysis (JON2104-B).

BACKGROUND

Systemic chemotherapy with gemcitabine plus S-1 (GEM + S-1), GEM + CDDP plus S-1 (GEM + CDDP + S-1), or gemcitabine plus cisplatin (GEM + CDDP) is standard treatment for advanced biliary tract cancer (aBTC). We aimed to evaluate the efficacy and safety of combination chemotherapy in older patients with aBTC.

METHODS

This multicenter prospective observational study (JON2104-B, UMIN000045156) included patients aged ≥ 70 years with aBTC. Inverse-probability weighting propensity-score analyses (IPW) were used to compare overall survival (OS) as the primary endpoint and progression-free survival (PFS) across treatment groups.

RESULTS

This study included 305 patients between August 2021 and January 2023. Of them, 75, 131, 26, 52, and 10 received GEM + CDDP + S-1, GEM + CDDP, GEM + S-1, gemcitabine, and S-1; their median ages were 74, 75, 77.5, 80, and 80 years, and approximately 24%, 16.8%, 23.1%, 9.6%, and 0% had G-8 scores of > 14, respectively. GEM + CDDP had a safety profile comparable to that of GEM + CDDP + S-1 but was more toxic than gemcitabine. Per IPW, the hazard ratio (HR) for GEM + CDDP + S-1 versus GEM + CDDP was 0.80 for OS (95% confidence interval [CI], 0.55-1.17) and 0.55 for PFS (95% CI 0.38-0.80). The HR for GEM + CDDP versus gemcitabine was 0.74 for OS (95% CI 0.42-1.29) and 0.79 for PFS (95% CI 0.42-1.49).

CONCLUSIONS

GEM + CDDP + S-1 was associated with longer PFS without additional toxicity than GEM + CDDP for fit older patients. However, the OS for both were not statistically different. The efficacies of GEM + CDDP and gemcitabine for vulnerable older patients did not also differ significantly. These findings highlight the importance of vulnerability in patients with aBTC.