Early detection of venous thromboembolism after the initiation of chemotherapy predicts a poor prognosis in patients with unresectable metastatic pancreatic cancer who underwent first-line chemotherapy with gemcitabine plus nab-paclitaxel

Background Pancreatic cancer is associated with a high thromboembolism risk. We investigated the significance of early venous thromboembolism (VTE) detection in patients with unresectable metastatic pancreatic cancer (UR-MPC) who received first-line chemotherapy with gemcitabine plus nab-paclitaxel (GnP). Methods This single-center retrospective study enrolled 174 patients with UR-MPC who underwent GnP as a first-line chemotherapy from April 2017 to March 2020. The early detection of VTE (deep venous thrombosis and pulmonary thromboembolism) was defined as diagnosis by the first follow-up CT scan after the initiation of chemotherapy. We compared the patients with early detection of VTE (VTE (+) group) with the others (VTE (-) group). We examined overall survival (OS), progress free survival (PFS), severe adverse events, and predictors associated with OS using the Cox proportional hazards model. Results Early detection of VTE was observed in 17 patients (9.8%). Thirteen patients were diagnosed with VTE at treatment initiation, and four patients were diagnosed after treatment initiation. The median time to diagnosis after treatment initiation was 55 days (range: 31-71 days). Only 3 patients were symptomatic. The VTE (+) group exhibited worse OS and PFS than the VTE (-) group (OS: 259 days vs. 400 days, P < 0.001; PFS: 120 days vs. 162 days, P = 0.008). The frequency of grade 3-4 adverse events was not significantly different. Although the performance status was poorer in the VTE (+) group, VTE was identified as a statistically significant independent predictor for OS in multivariate analyses (HR, 1.87; 95% CI, 1.02-3.44; P = 0.041). Conclusions Early VTE detection is a predictor of a poor prognosis in UR-MPC patients who receive GnP as first-line chemotherapy, suggesting that screening VTE for patients with UR-MPC is crucial, even if patients are asymptomatic.