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.