Pulmonary Embolism after Major Abdominal Surgery in Gynecologic Oncology
Abstract & Commentary
By Robert L. Coleman, MD, Associate Professor, University of Texas; M.D. Anderson Cancer Center, Houston, is Associate Editor for OB/GYN Clinical Alert.
Dr. Coleman is on the speaker’s bureau for GlaxoSmithKline, Bristol-Myers Squibb, and Ortho Biotech.
Synopsis: Patients with cancer undergoing major abdominal surgery and using pneumatic compression for thromboembolic prophylaxis had 14-fold greater odds of developing a pulmonary embolism compared with patients with benign disease. Randomized studies are needed to determine whether additional prophylactic measures may benefit this high-risk group of patients.
Source: Martino M, et al. Pulmonary Embolism After Major Abdominal Surgery in Gynecologic Oncology. Obstet Gynecol. 2006;107:666-671.
Venous Thromboembolism (VTE) is a major complication following gynecologic abdominal surgery that may be fatal in up to 1 in 4 affected patients. While several risk factors for VTE have been identified, carcinoma remains among the most significant. Incidence rates of VTE in gynecologic cancer patients are estimated to be among the highest of all primary carcinoma sites. Martino and colleagues conducted a retrospective cohort study to evaluate the incidence of VTE among gynecologic cancer patients who had undergone surgery at their center over a 3-year period. Both major (n = 839) and minor (n = 507) procedures were evaluated among patients with known or suspected malignancy. Surgical VTE prophylaxis was pneumatic compression boots alone. Cancer diagnosis, age, and type of surgery (major vs minor) were evaluated in the context of VTE which was confirmed by spiral CT, pulmonary angiography or ventilation/perfusion scans. Overall, 22 cases of VTE were diagnosed among the 839 patients undergoing major abdominal surgery. Twenty-one of 507 (4.1%) cancer patients were identified with VTE—a mean 11 days post-operatively. Only 1 of 332 (0.3%) patients with benign disease were diagnosed with VTE. The odds ratio for VTE in cancer patients relative to those with benign disease was 13.8 (P < 0.001). Other factors identified with increased risk were ovarian cancer and age. Survival was statistically unaffected by the occurrence of VTE. The authors concluded that patients undergoing major abdominal surgery and using pneumatic compression devices for prophylaxis had 14-fold greater odds of developing a pulmonary embolus than patients with benign disease. The incidence of VTE identified in this study provides important baseline information upon which to develop randomized clinical trials to improve prophylaxis.
Commentary
The clinical evaluation of VTE prophylaxis among patients with gynecologic malignancy has spanned more than 20 years. In 1983, Clarke-Pearson and colleagues conducted 2 randomized, controlled clinical trials of heparin and pneumatic compression to controls and confirmed that the latter was effective in preventing VTE. Pneumatic compression in that study was administered before surgery and continued for 5 days post operatively. The 2 modalities were studied against each other in a follow-up trial 10 years later documenting equivalency in the prevention of VTE. However, patients receiving heparin experienced bleeding complications. With the development of low molecular weight heparin (LWMH), Maxwell and colleagues re-evaluated this therapy compared to pneumatic compression in gynecologic oncology patients. In this randomized trial, both were effective in preventing VTE and bleeding complications were similar, prompting the authors to recommend either as a reasonable option for VTE prophylaxis in this cohort. Nonetheless the current trial, consistent with others in the literature, document that nearly 1 in 20 cancer patients and nearly 1 in 15 ovarian cancer patients will suffer a VTE under one of these recommended prophylaxis strategies. Clearly, this represents an important area of clinical investigation. While a small trial combining LWMH and compression boots was unable to document an improvement over single modality prophylaxis, it remains to be seen if other combination strategies can "move the bar" in VTE prophylaxis. Given the low overall absolute risk of VTE as identified in the current study, such trials will be necessarily large and focused in the gynecologic oncology population. Fortunately, the Gynecologic Oncology Group is currently developing such a study.
Suggested Reading
- Maxwell GL, et al. Pneumatic compression versus low molecular weight heparin in gynecologic oncology surgery: a randomized trial. Obstet Gynecol. 2001;98:989-995.
- Geerts WH, et al. Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Chest. 2004;126(Suppl):338S-400S.
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