Risk factors for venous thromboembolism in patients undergoing neoadjuvant chemotherapy as treatment for ovarian cancer

Objective: During the treatment of ovarian cancer, the risk of venous thromboembolism (VTE) post operatively is well established, however, patients may be at even greater risk during neoadjuvant chemotherapy (NACT). This study aimed to determine the incidence and timing of VTE amongst patients undergoing NACT, whether there was an association with survival, and examine risk factors associated with the development of VTE.

Study design: This was a retrospective cohort study of patients diagnosed with ovarian, fallopian tube and primary peritoneal cancer receiving neoadjuvant chemotherapy betweenApril 2011 and April 2022 at a gynaecological cancer centre in England. Clinical factors examined included: age at diagnosis, Body Mass Index (BMI), presence of inflammatory co-morbidity, tumour morphology, stage of disease, pelvic mass,ascites,retroperitoneal lymphadenopathy, Khorana score, serum albumin levels, chemotherapy regime, bevacizumab administration and Ca 125 levels.

Results: Of 304 patients analysed, 73 (24%) patients developed venous thromboembolism. Of the patients who developed VTE, fifty-five patients developed pulmonary embolism (75%) and the stage of treatment at which most VTEs were diagnosed was neoadjuvant chemotherapy (32%). There was no correlation observed, between the incidence of VTE and any risk factors, including Khorana score, with the exception of low albumin (<35 g/L)(odds ratio (OR):2.1(95%CI 1.1-3.9; p = 0.06) and patients who did not receive paclitaxel chemotherapy (OR:2.04(95%CI 1.02-4.05; p = 0.08). There was no difference in survival rates between the VTE group and the non-VTE group.

Conclusion: This study demonstrates high rates of VTE, especially pulmonary embolism, in ovarian cancer patients undergoing NACT. The present study, amongst others in the literature also suggest that the risk of VTE in ovarian cancer patients undergoing NACT is underestimated by current risk stratification models. Therefore, prospective trials dedicated to ovarian cancer patients specifically, and a development of a risk model that takes into account factors established by higher levels of evidence, are strongly recommended.