Venous thromboembolism incidence in postoperative breast cancer patients.

Background: Venous Thromboembolism (VTE) is an important cause of morbidity in cancer patients. Breast cancer patients undergoing surgical treatment are at an increased risk of VTE. The aim of this study was to determine the frequency of VTE in patients who underwent surgery for the treatment of breast cancer and to identify the related risk factors.

Methods: A historical cohort of patients at the São Paulo State Cancer Institute (ICESP) underwent surgery for breast cancer. The inclusion criteria covered patients with invasive breast cancer or ductal carcinoma in situ who had breast surgery anytime from January 2016 to December 2018.

Results: Of the 1672 patients included in the study, 15 had a confirmed diagnosis of VTE (0.9%), and 3 of these had deep vein thrombosis (0.2%), and 12, had pulmonary thromboembolism (0.7%). Clinical and tumoral characteristics did not differ between the groups. The incidence of VTE was higher in patients who had undergone skin-sparing mastectomy or nipple-sparing mastectomy (p = 0.032). Immediate reconstruction, particularly with abdominal-based flaps (4.7%), increased VTE events (p = 0.033). Median surgical time was higher in patients with VTE episodes (p = 0.027), and total hospital length of stay increased in days (6 days vs. 2 days, p = 0.001). Neoadjuvant chemotherapy and postoperative prophylaxis with Low Molecular Weight Heparin (LMWH) were associated with lower VTE rates (0.2% vs. 1.2%, p = 0.048 and 0.7% vs. 2.7%, p = 0.039; respectively) in these patients.

Conclusions: The incidence of VTE events in breast cancer patients who underwent surgery was 0.9%. Immediate reconstruction (especially with abdominal-based flaps), skin-sparing/nipple-sparing mastectomies, and longer surgeries were associated with increased risk. The LMWH postoperative prophylaxis reduced this risk.