Time to treatment initiation and its impact on real-world survival in metastatic colorectal cancer and pancreatic cancer

Background Given the dearth of data regarding the time to treatment initiation (TTI) in the palliative setting, and its impact on survival outcomes, we sought to determine TTI in a real-world cohort of metastatic colorectal cancer (mCRC) and metastatic pancreatic cancer (mPC) patients and evaluate the impact of TTI on real-world survival outcomes. Methods We collected survival and treatment data for mCRC and mPC from the Flatiron Health electronic health records (EHR) derived database. We divided TTI into 3 categories: < 2 weeks, 2-< 4 weeks, and 4-8 weeks, from diagnosis to first-line therapy. Outcome measures were median TTI, real-world overall survival (RW-OS) based on TTI categories by Kaplan-Meier method, and impact of TTI on survival using cox proportional hazard models. Results Among 7108 and 3231 patients with mCRC and mPC treated within 8 weeks of diagnosis, the median TTI were 28 days and 20 days. Median RW-OS for mCRC was 24 months; 26.9 months versus 22.6 and 18.05 months in the 4-8-week, 2-< 4 week (control) and < 2-week groups, respectively (p < 0.0001). For mPC, median RW-OS was 8 months, without significant difference in RW-OS among the groups (p = 0.05). The 4-8-week group was associated with lower hazard of death (HR 0.782, 95% CI 0.73-0.84, p < 0.0001) and the < 2-week group was associated with a higher hazard of death (HR 1.26, 95% CI 1.15-1.38, p < 0.0001) in mCRC. The 4-8-week group was associated with lower hazard of death for mPC (HR 0.88, 95% CI 0.8-0.97, p = 0.0094). Conclusion In a real-world cohort of patients treated within 8 weeks of diagnosis, and with the limitations of a retrospective study, later TTI did not have a negative impact on survival outcomes in mCRC and mPC.