ASCOT

Regimen

Experimental
S-1 (tegafur/gimeracil/oteracil) 80-120 mg/day (based on body surface area) days 1-28 q6w × 4 cycles (24 weeks)
Control
Observation

Population

Resected biliary tract cancer (ICC ~30%, ECC ~49%, GBC ~22%), R0 resection, Japan multicenter (JCOG); all Japanese patients; Stage I-III disease

Key finding

ASCOT is the cleanest positive adjuvant BTC phase 3 trial to date, demonstrating a statistically significant 31% reduction in death risk with oral S-1 versus observation. Unlike BILCAP, ASCOT hit its ITT primary endpoint without controversy. The absolute benefit translates to approximately 11 months median OS improvement. Subgroup analyses suggested benefit across ICC, ECC, and GBC, though GBC numbers were smaller. The trial is limited to Japanese patients and S-1 PK/tolerability differs by ethnicity (East Asian populations tolerate S-1 better due to lower DPD activity). Whether results extend to capecitabine (a related fluoropyrimidine) in Western populations is inferred but not proven.

Source: PMID 36681415

Timeline

    Guideline citations

    • NCCN BTC (p.97)