The efficacy and safety of low-molecular-weight heparins for venous thromboembolism prophylaxis in abdominal or pelvic cancer surgery: A systematic review and network meta-analysis of randomized controlled trials

Background: Low-molecular-weight heparins (LMWHs) have been widely used for thromboprophylaxis in postoperative patients with abdominal or pelvic cancer. However, evidence regarding the optimal type of LMWHs remains limited. Objective: This study aims to evaluate the efficacy and safety of different types of LMWHs in patients undergoing abdominal or pelvic cancer surgery through a network meta-analysis of randomized controlled trials (RCTs). Methods: The network meta-analysis was guided by the PRISMA guidelines. The primary outcomes included venous thromboembolism (VTE), major bleeding, and all-cause death. Results were summarized with relative ratios (RR) and 95 % confidence intervals (CIs). The surface under the cumulative ranking curve (SUCRA) was calculated to assess the performance of various LMWHs. Results: A total of 19 RCTs involving 6318 patients were identified. Compared to non-LMWH, LMWHs significantly reduced the risk of VTE [RR 0.57, (95 % CI 0.41-0.81)], DVT [RR 0.56, (95 % CI 0.39-0.81)], and PE [RR 0.26, (95 % CI 0.10-0.66)], without increasing the risk of all-cause death [RR 0.67, (95 % CI 0.39-1.14)], major bleeding [RR 1.51, (95 % CI 0.82-2.77)], minor bleeding [RR 1.23, (95 % CI 0.84-1.80)], all bleeding [RR 1.35, (95 % CI 0.98-1.84)], or thrombocytopenia [RR 0.41, (95 % CI 0.13-1.31)]. Notably, no significant differences in efficacy and safety were observed among different types of LMWHs, with parnaparin (SUCRA 86.3), dalteparin (SUCRA 74.5), and certoparin (SUCRA 88.5) ranking highest in the prevention of VTE, major bleeding, and allcause death, respectively. Conclusion: LMWHs are efficacious options for thromboprophylaxis in patients undergoing abdominal or pelvic cancer surgery, without increasing the risk of major bleeding or all-cause death. However, no significant differences were observed in efficacy and safety among different types of LMWHs used in this context.