Incidence of postoperative thrombotic events in ovarian cancer patients with a de-escalated prophylactic strategy: A retrospective cohort study

Objective: This study aimed to determine the incidence of thrombotic events in ovarian cancer patients following a de-escalated prophylactic strategy and to stratify risk groups. Methods: We reviewed the records of patients who underwent debulking surgery for ovarian cancer at a single institution between January 2007 and May 2019. We identified clinically diagnosed and radiologically confirmed cases of thrombotic events—classified as pulmonary thromboembolism (PE), deep vein thrombosis (DVT), and other thrombotic events—within 6 months of debulking surgery. Results: After excluding 13 patients diagnosed with thromboembolism at the baseline or during neoadjuvant chemotherapy, 799 were analyzed. Since the introduction of medical prophylaxis at our institution in 2009, 482 patients (60%) received medical prophylaxis with subcutaneous injection of low molecular weight heparin for 5 days with mechanical prophylaxis, whereas 317 (40%) received mechanical prophylaxis only. After debulking surgery, thrombotic events occurred in 28 patients (3.5%) including PE (n = 11), DVT (n = 10), and other thrombotic events (n = 7). Multivariable analysis identified age, body mass index (BMI), and operative duration as independent risk factors associated with thrombotic events. A thrombotic event was an independent prognostic factor for overall survival (HR 2.17, 95% CI 1.16–4.1). A cut-off analysis for pre-operative identifiable risk factors showed age < 57 years and BMI < 21 could help define low-risk groups. One patient from 172 low-risk patients (0.58%) experienced a thrombotic event. Conclusions: The thrombotic event incidence was low in our cohort. A de-escalated prophylaxis strategy may be considered in young (age < 57 years) and lean (BMI < 21) patients.