Venous thromboembolism (VTE) is a common occurrence in cancer patients. Those undergoing major operations are at higher risk of deep vein thrombosis (DVT), a condition that occurs when blood in the vein pools, usually in the calf or thigh, and forms a clot. The consequences can be serious because the blood clot can break loose from the leg vein, travel to the lungs and block the blood vessels that supply the lungs. This complication, called a pulmonary embolism, can be fatal.
Administering blood-thinning drugs such as heparin after surgical procedures has become a common practice. However, no large studies have investigated the safety and efficacy of giving a single preoperative dose of blood thinners, in addition to post-operative doses, to patients undergoing major cancer operations. Administering blood-thinners before operatives can sometimes lead to excessive bleeding, transfusions, and other serious issues.
A new study published in the Journal of the American College of Surgeons revealed that the preoperative use of blood-thinning drugs does not increase rates of major bleeding or transfusions, and is associated with a decreased risk of blood clots, among patients undergoing major cancer operations.
Study coauthor Dr. Vivian Strong, an associate attending surgeon and NSQIP surgical champion at MSKCC, said, "We weren't sure if our VTE rate was due to the complexity of our operations, the fact that our patients had cancer, or that we weren't administering heparin, which could decrease the blood clots. There was serious concern that administering preoperative VTE prophylaxis to our patients, who undergo extensive surgical resection, would increase the risk of bleeding."
Lead study author Dr. Luke V. Selby, the department of surgery's outcomes research fellow, said, "Knowing, from NSQIP, that we had a higher than expected VTE rate, the question was whether it was safe to expose our patients to the additional bleeding risk from VTE prophylaxis."
For this study, Dr. Selby and colleagues selected 2,058 patients undergoing major operations for cancer at MSKCC to receive preoperative VTE prophylaxis (low-molecular-weight heparin or unfractionated heparin). The investigators then compared bleeding, transfusion, and VTE rates from that cohort of cancer patients with a group of 4,960 cancer patients who had already undergone a major surgical procedure a year earlier, but did not receive preoperative VTE prophylaxis.
The study findings showed that providing one dose of anticoagulant medicines before surgery is safe in cancer patients undergoing major operations. Patients who had received preoperative VTE prophylaxis had lower transfusion rates (17% versus 14%) without a difference in major bleeding. In addition, rates of deep vein thrombosis and pulmonary embolism were significantly lower in the VTE prophylaxis group (1.3% versus 0.2%; and 1% versus 0.4%, respectively).
Dr. Strong said, "Because of the findings from this study, Memorial Sloan Kettering Cancer Center has adopted a routine anticoagulation approach for patients who meet certain selection criteria. This research has been a practice-changing study for our institution. Our study results demonstrate to other institutions that you can use preoperative VTE prophylaxis safely, so I think that it has very broad-reaching, practice-changing implications."