Early tumor shrinkage (ETS) and depth of response (DpR) are effective tools for prognostication in patients with advanced, chemotherapynaïve biliary tract cancer, according to findings published in The Oncologist. Investigators assessed the association of ETS and DpR with clinical outcomes among 354 patients (289 with measurable target lesions) who were categorized into ETS unachieved and ETS-achieved groups (≥20% tumor reduction at week 6) and DpR-low and DpR-high groups (≥40% maximum shrinkage) until 12 weeks after enrollment. HRs for progression-free survival (PFS) and overall survival (OS) in the ETS-achieved group were 0.70 (95% CI, 0.52-0.93) and 0.60 (95% CI, 0.44-0.81), respectively. HRs for PFS and OS in the DpR-high group were 0.67 (95% CI, 0.48-0.94) and 0.64 (95% CI, 0.46-0.90), respectively. Results of a subpopulation treatment effect pattern plot analysis showed that most patients who had ETS with combination chemotherapy did not experience disease progression after 12 weeks.
