PO22 | LONG-TERM ANTICOAGULANT THERAPY AND REDUCTION OF OVARIAN CANCER RECURRENCE: CLINICAL EVIDENCE OF A POTENTIAL ANTITUMOUR EFFECT

J. Khizroeva¹, V. Bitsadze¹, A. Vorobev¹, A. Solopova¹, M. Tretyakova¹, N. Gashimova¹, K. Grigoreva¹, A. Khisamieva¹, J. Gris^1|2, I. Elalamy^1|3|4, G. Gerotziafas^1|3|4, A. Makatsariya¹ | ¹Department of Obstetrics, Gynecology and Perinatal Medicine, N. F. Filatov Clinical Institute of Children’s Health, I. M. Sechenov First Moscow State Medical University, Moscow, Russia; ²Faculty of Pharmaceutical and Biological Sciences, Montpellier University, France; ³Department Hematology and Thrombosis Center, Medicine Sorbonne University, Paris, France; ⁴Hospital Tenon, Paris, France

Background. Activation of the hemostatic system is a key component of tumor progression and metastasis in advanced ovarian cancer. Anticoagulant therapy (ACT), traditionally used for the prevention of venous thromboembolism (VTE), may interfere with these mechanisms and potentially modify tumor recurrence and carcinogenesis.

Aim. The aim is to evaluate the impact of long-term ACT on ovarian cancer recurrence in patients with stage III-IV epithelial ovarian cancer.

Methods. A prospective interventional non-randomized comparative study included 126 patients with stage III-IV epithelial ovarian cancer. The main group (n=66) received DOACs for 60-72 months as secondary prevention of VTE, while the comparison group (n=60) did not receive ACT. Both groups were comparable in age, disease stage, and extent of antitumour treatment. DOACs were used: dabigatran 50 mg twice daily, rivaroxaban 10 mg once daily, or apixaban 2.5 mg twice daily, with individualized selection based on renal function and clinical profile. The primary outcome was ovarian cancer recurrence; thrombotic events were also recorded.

Results. During long-term follow-up, ovarian cancer recurrence was observed in 21 of 66 patients (31.8%) receiving ACT, compared with 39 of 60 patients (65.0%) in the comparison group (p<0.05), indicating a nearly twofold reduction in recurrence rate associated with long-term anticoagulation. The rate of VTE was similar in both groups: 18.2% in the group that was taking anticoagulants and 16.7% in the group that was not. In the anticoagulant group, thrombotic events included DVT in 12.1% and PE in 6.1% of patients. Despite similar rates of thrombotic complications, long-term ACT was associated with a marked decrease in tumor recurrence, suggesting an effect beyond thromboprophylaxis. The observed benefit persisted throughout extended follow-up, supporting a sustained modification of tumor progression dynamics.

Conclusions. Long-term anticoagulant therapy for 60-72 months significantly reduces tumor recurrence in patients with advanced epithelial ovarian cancer without increasing thrombotic events. These findings support the hypothesis that anticoagulants may exert an additional antitumor effect by interfering with hemostasis-dependent mechanisms of invasion and metastasis. ACT may therefore represent a potential modifier of cancer recurrence and carcinogenesis, warranting further investigation in randomized controlled trials.