Risk of thrombosis and bleeding in gynecologic cancer surgery: systematic review and meta-analysis

OBJECTIVE To provide procedure-specific estimates of the risk of symptomatic venous thromboembolism (VTE) and major bleeding, in the absence of thromboprophylaxis, following gynecologic cancer surgery. DATA SOURCES We conducted comprehensive searches on Embase, MEDLINE, Web of Science, and Google Scholar for observational studies. We also reviewed reference lists of eligible studies and review articles. We performed separate searches for randomized trials addressing effects of thromboprophylaxis and conducted a web-based survey on thromboprophylaxis practice. STUDY ELIGIBILITY CRITERIA Observational studies enrolling ≥50 adult patients undergoing gynecologic cancer surgery procedures reporting absolute incidence for at least one of the following: symptomatic pulmonary embolism, symptomatic deep vein thrombosis, symptomatic VTE, bleeding requiring reintervention (including re-exploration and angioembolization), bleeding leading to transfusion or post-operative hemoglobin <70 g/L. STUDY APPRAISAL AND SYNTHESIS METHODS Two reviewers independently assessed eligibility, performed data extraction, and evaluated risk of bias of eligible articles. We adjusted the reported estimates for thromboprophylaxis and length of follow-up and used the median value from studies to determine cumulative incidence at 4 weeks post-surgery stratified by patient VTE risk factors, and used the GRADE approach to rate evidence certainty. RESULTS We included 188 studies (398,167 patients) reporting on 37 gynecologic cancer surgery procedures. The evidence certainty was generally low to very low. Median symptomatic VTE risk (in the absence of prophylaxis) was <1% in 13 of 37 (35%) procedures, 1%-2% in 11 of 37 (30%), and >2.0% in 13 of 37 (35%). The risks of VTE varied from 0.1% in low VTE risk patients undergoing cervical conization to 33.5% in high VTE risk patients undergoing pelvic exenteration. Estimates of bleeding requiring reintervention varied from <0.1% to 1.3%. Median bleeding requiring reintervention risks were <1% in 22 of 29 (76%) and 1%-2% in 7 of 29 (24%) procedures. CONCLUSIONS VTE reduction with thromboprophylaxis likely outweighs increase in bleeding requiring reintervention in many gynecologic cancer procedures (e.g., open surgery for ovarian cancer and pelvic exenteration). In some procedures (e.g., laparoscopic total hysterectomy without lymphadenectomy), thromboembolism and bleeding risks are similar, and decisions depend on individual risk prediction and values and preferences regarding VTE and bleeding.