Real-world overall survival of patients diagnosed with recurrent versus de novo metastatic pancreatic ductal adenocarcinoma (PDAC).

Abstract

e16250 Background: PDAC is a lethal malignancy which accounted for the third most cancer related deaths in 2020. Patients (pts) who are initially diagnosed with stage I-III PDAC have a 5-year relative survival of 13.3 – 39.4%; those with metastatic disease at diagnosis have a 5-year relative survival of 2.9%. Limited data are published comparing the outcomes of pts with stage I-III who develop metastases (recurrent) compared to pts with de novo mPDAC (de novo). This analysis seeks to compare demographic, clinical characteristics, and survival outcomes of pts with recurrent versus de novo mPDAC in a community oncology setting. Methods: Using the Flatiron Health database, a retrospective observational study was conducted abstracting deidentified data from ≥280 US cancer clinics. Pts with mPDAC diagnosed from 01/2016 to 08/2020 with a known stage at initial diagnosis were included. Pts were stratified based on initial stage at diagnosis. Median overall survival (OS) from time of metastasis was derived using Kaplan-Meier analysis. Unadjusted and multivariable Cox proportional hazards models were used to compare survival between recurrent and de novo cohorts. Results: N = 6,543 pts analyzed; 70.1% (n = 4,586) had de novo mPDAC and 29.9% (n = 1,957) had recurrent mPDAC. Median age at time of metastasis was similar for both cohorts: 69 years (IQR: 62 – 76). The most common site of primary tumor location was head for both cohorts (recurrent mPDAC: 69.8%; de novo mPDAC: 40.3%). Approximately 45% of pts with recurrent mPDAC underwent a Whipple procedure (pre diagnosis of metastasis). A similar proportion of pts in both cohorts received treatment in the metastatic setting (recurrent mPDAC: 74.3%; de novo mPDAC: 77.3%). Pts with recurrent mPDAC had a longer median OS compared to the de novo cohort: 8.0 months (95% CI: 7.5 – 8.6) versus 6.1 (95% CI: 5.7 – 6.4) [unadjusted hazard ratio (HR): 0.79 (95% CI: 0.74 – 0.84); adjusted HR: 0.73 (0.68 – 0.78), p < 0.0001]. Conclusions: The results of this real-world study indicate that pts with recurrent mPDAC are more likely to have a head primary and to experience longer OS from time of metastasis than those with de novo mPDAC. These data suggest stratification for clinical trial enrollment for recurrent vs de novo is necessitated.