ABSTRACT
Background: The COVID-19 pandemic caused disruptions in cancer care delivery and forced oncologists to make recommendations about safely delaying initiation of cancer therapy. Compared to the adjuvant, curative setting, there is a scarcity of information about the impact of time to treatment initiation on outcomes in the palliative setting for gastrointestinal malignancies. We sought to determine the median time to initiation of systemic therapy (TIT) in mPC in the US prepandemic, and to assess the impact of TIT on survival outcomes. Methods: We retrospectively analyzed de-identified data of patients with mPC in the Flatiron Health nationwide EHRderived database. Metastatic diagnosis dates between 01/2014 and 04/2020 were included. Demographics, treatments, and outcomes were collected. TIT was defined as period between diagnosis and initiation of first-line systemic therapy and was split into 3 categories (I: < 2 weeks, II: 2- <4 weeks, and III: 4-8 weeks). Overall survival (OS) was defined from time of diagnosis to time of death. Post-chemotherapy survival (PCS) was time from initiation of firstline therapy to death. Adjusted and unadjusted multinomial logistic regression were used to evaluate the association of demographics and clinical factors with TIT. PCS and OS were estimated with Kaplan-Meier curves. Adjusted (demographics and clinical factors) Cox proportional hazard models were used to estimate the effect of TIT groups on PCS and OS. Category II served as control group. Results: 3231 patients with mPC who received at least one line of treatment were identified. 29% (N= 947), 43% (N=1375), and 28% (N= 909) were in TIT categories I-III respectively. The mean age at diagnosis was 67.4 years, with no significant difference in age (P=0.14) among categories. Median TIT was 20 days. Multinomial logistic regression showed that compared to TIT II, Black patients were less likely than White patients to receive chemotherapy in less than 2 weeks (P=0.02), and those who had recurrent disease were more likely to receive therapy in less than 2 weeks (P< 0.0001). There was no significant difference in median RW OS among the groups (I: 8.13, II: 8.07, III: 9.02 months, P=0.0532). RW PCS was also similar across categories (I: 7.8, II: 7.5, III: 7.8 months, P=0.88). Adjusted cox regression analysis suggests that compared to TIT of 2-4 weeks, TIT 4-8 weeks was associated with higher RW OS (HR, 0.88, 95% CI 0.8-0.97, P=0.009), but not RW PCS (HR, 0.95, 95% CI 0.87-1.05, P=0.32). Conclusions: This real-world analysis suggests that pre-pandemic, most patients with mPC who receive 1st line therapy were treated within 4 weeks of diagnosis. Compared to TIT of 2-4 weeks, TIT 4-8 weeks was associated with higher RW OS in mPC, although the clinical significance is minimal. In crisis situations, efforts to clinically optimize patients with mPC before systemic therapy should continue to be pursued.