Preoperative oncologic therapy and the prolonged risk of venous thromboembolism in resectable pancreatic cancer

BACKGROUND: Pancreatic cancer is one of the most prothrombotic cancers. Among patients receiving preoperative chemotherapy followed by surgery, chemotherapy and surgery represent a compound risk for venous thromboembolism (VTE), rendering the postoperative time a period of interest. We aimed to analyze whether preoperative oncologic therapy increases the risk for VTE after surgery and identify which characteristics associate with VTE. METHODS: We first identified patients surgically treated for pancreatic cancer at Helsinki University Hospital between 2000 and 2017, collecting the following data: gender, age at surgery, preoperative medication, body mass index (BMI), preoperative chemo(radio)therapy, tumor size, positive node ratio, perineural and perivascular invasion, tumor grade, surgical technique, postoperative anticoagulation, adjuvant therapy, time of VTE, time of local disease recurrence, time of distant metastasis, and time of death. With a follow‐up period of at least 2 years or until death, we compared a total of 93 preoperative oncologic therapy and 291 upfront surgery patients (n = 384, median age 66.5 years). RESULTS: Preoperative oncologic therapy increased the risk for thrombosis after surgery (hazard ratio [HR] 1.61; 95% confidence interval [CI] 1.03–2.53). The VTE incidence rate remained high for up to 2 years after surgery. BMI ≥30 kg/m(2), prior anticoagulation, and disease recurrence (p < 0.05, respectively) associated with VTE. VTE is also associated with shorter overall survival (HR 3.25; 95% CI 2.36–4.44). In 71.6% (95% CI 60.5–81.1) of patients, VTE was diagnosed after disease recurrence. CONCLUSIONS: Preoperative oncologic therapy represents an independent risk factor for VTE, not only during the immediate postoperative period but up to 2 years after surgery. VTE is associated with obesity, prior anticoagulation, and disease recurrence and diminishes overall survival.