To identify the incidence and timing of venous thromboembolism as well as any associated risk factors in patients with ovarian, fallopian tube, or primary peritoneal cancer undergoing neoadjuvant chemotherapy.

We conducted a retrospective cohort study of patients diagnosed with ovarian, fallopian tube, and primary peritoneal cancer and receiving neoadjuvant chemotherapy from January 2009 to May 2014 at a single academic institution. The timing and number of venous thromboembolic events for the entire cohort were categorized as follows: presenting symptom, during neoadjuvant chemotherapy treatment, after debulking surgery, and during adjuvant chemotherapy.

Of the 125 total patients with ovarian cancer undergoing neoadjuvant chemotherapy, 13 of 125 patients (10.4%, 95% confidence interval [CI] 6.1-17.2%) had a venous thromboembolism as a presenting symptom and were excluded from further analysis. Of the 112 total patients at risk, 30 (26.8%, 95% CI 19.3-35.9%) experienced a venous thromboembolism. Based on the phase of care, 13 (11.6%, 95% CI 6.8-19.1%) experienced a venous thromboembolism during neoadjuvant chemotherapy, six (5.4%, 95% CI 2.4-11.5%) developed a postoperative venous thromboembolism, and 11 (9.9%, 95% CI 5.5-17%) developed a venous thromboembolism during adjuvant chemotherapy. Two of the four patients with clear cell histology developed a venous thromboembolism in this cohort.

Overall new diagnosis of venous thromboembolism was associated with one fourth of the patients undergoing neoadjuvant chemotherapy for ovarian cancer with nearly half of these diagnosed during chemotherapy cycles before interval debulking surgery. Efforts to reduce venous thromboembolism so far have largely focused on the postoperative period. Additional attention to venous thromboembolic prophylaxis during chemotherapy (neoadjuvant and adjuvant) in this patient population is warranted in an effort to decrease the rates of venous thromboembolism.