Hemorrhagic and Thrombotic Abnormalities of Cancer

Bleeding and thrombotic complications in critically ill patients with cancer

Alterations in hemostasis are common in patients with cancer admitted to the ICU. Depending on the underlying disease and specific hemostatic abnormality, the patient with cancer may develop bleeding, thrombosis, or both, such as DIC. Bleeding complications usually result from abnormalities in platelets or deficiency of coagulation factors and require specific blood or coagulation factor replacement. Similarly, critically ill patients with cancer are predisposed to thrombotic complications such as DVT, PE, and central vein thrombosis, the last as a result of the widespread use of long-term indwelling catheter devices. Advances in diagnostic imaging and the availability of newer and more potent anticoagulant agents have facilitated the care of these patients greatly. Ultimately, it is hoped that a thorough understanding of the various disturbances in hemostasis, innovative treatment approaches, and implementation of preventive strategies in patients with cancer will lead to decreased morbidity and improved survival rates of critically ill patients with cancer in the ICU.

Incidence of recurrent thromboembolic and bleeding complications among patients with venous thromboembolism in relation to both malignancy and achieved international normalized ratio: a retrospective analysis

PURPOSE

Initial heparinization followed by vitamin K antagonists is the treatment of choice for patients with venous thromboembolism. There is controversy whether known malignancy is a risk factor for recurrences and bleeding complications during this treatment. Furthermore, the incidence of such events in these patients is dependent on the achieved International Normalized Ratio (INR). The aim of this study was to assess the incidence of venous thromboembolic recurrence and major bleeding among patients with venous thromboembolism in relation to both malignancy and the achieved INR.

PATIENTS AND METHODS

In a retrospective analysis, the INR-specific incidence of venous thromboembolic and major bleeding events during oral anticoagulant therapy was calculated separately for patients with and without malignancy. Eligible patients participated in two multicenter, randomized clinical trials on the initial treatment of venous thromboembolism. Patients were initially treated with heparin (standard or low-molecular weight). Treatment with vitamin K antagonists was started within 1 day and continued for 3 months, with a target INR of 2.0 to 3.0.

RESULTS

In 1,303 eligible patients (264 with malignancy), 35 recurrences and 12 bleeds occurred. Patients with malignancy, compared with nonmalignant patients, had a clinically and statistically significantly increased overall incidence of recurrence (27.1 v 9.0, respectively, per 100 patient-years) as well as bleeding (13.3 v 2.1, respectively, per 100 patient-years). In both groups of patients, the incidence of recurrence was lower when the INR was above 2.0 compared with below 2.0.

CONCLUSION

Although adequately dosed vitamin K antagonists are effective in patients with malignant disease, the incidence of thrombotic and bleeding complications remains higher than in patients without malignancy.

Cell surface expression of lysosome-associated membrane protein-2 (lamp2) and CD63 as markers of in vivo platelet activation in malignancy

Platelets may become activated in vivo in a number of prethrombotic conditions including cancer. In the present study, cell surface expression of lysosome-associated membrane protein-2 (lamp2) and CD63 (lamp3) were examined by flow cytometry in 15 healthy volunteers and 5 patients with metastatic cancer to determine their utility as markers of in vivo platelet activation. Unstimulated platelets from controls had low levels of lamp2 expression, in contrast to cancer patients, who had significantly elevated levels (3.79 +/- 1.48% vs 33.9 +/- 5.6%). Upon stimulation with collagen, a greater than two-fold increase in the number of platelets expressing detectable levels of lamp2 was seen only among controls and not in cancer patients. Stimulation with collagen also resulted in a nearly two-fold increase in the proportion of platelets expressing CD63 in the control group, and a less than 1.5-fold increase in CD63 was seen in the patient group. The results suggest that cell surface lamp2 and CD63, like cell surface expression of GMP-140, may be good indicators of in vivo platelet activation and may be potentially useful in identifying patients with prethrombotic disorders.

Perioperative care of the oncology patient

Cancer patients are often at high risk for perioperative complications because of preexisting conditions, the magnitude of surgery, and the use of aggressive multimodality treatment. It is essential to identify risk factors preoperatively, correct any deficits, and monitor organ dysfunction. During the perioperative period prophylaxis and surveillance for cardiopulmonary, hematologic, and septic complications should minimize morbidity and mortality. Finally, nutritional support should be given to malnourished patients undergoing extensive operative procedures.

Immunohistochemical identification of tissue factor in solid tumors

Patients with cancer experience a much higher than expected incidence of thromboembolic disorders, commonly referred as Trousseau syndrome. Although this association has been well documented, the etiology of the hypercoagulable state is not known. The expression on tumor cells of tissue factor (TF), a membrane-bound lipoprotein that functions as a cofactor to factor VIIa in the initiation of the extrinsic pathway of blood coagulation, has been postulated as a possible mechanism. Whereas the distribution of TF in normal tissues is known, no large survey of TF expression in malignant tissues has been reported. In this study a polyclonal, monospecific rabbit anti-human TF IgG was used for immunohistochemical localization of TF antigen in 85 different tumor specimens. In general, cell types which normally express TF continued to do so after malignant transformation (41 of 60 epithelial tumor specimens were positive for TF). Tumors of nonepithelial origin frequently lacked TF, with only 3 of 19 specimens containing evidence of TF antigen. In addition five of six benign tumors did not express TF. Many tumor types commonly associated with Trousseau syndrome, for example lung, pancreatic, breast, colon and gastric carcinomas, stained positively for TF. Based on this survey, it appears that TF expression by tumors may be an important factor in the pathogenesis of a hypercoagulable state in some patients with cancer.

Thromboembolic complications in patients with advanced cancer: anticoagulation versus Greenfield filter placement

Thirty patients with Stage III/IV cancer and thromboembolic complications between 1987-89 were reviewed. Twelve patients had a deep venous thrombosis proximal to the calf diagnosed by duplex scanning or contrast venography, 15 patients had a pulmonary embolism diagnosed by a high-probability pulmonary ventilation/perfusion scan or arteriogram, and three patients had both deep vein thrombosis and pulmonary embolism. Patients were treated primarily with anticoagulation (Group A = 20 patients) or a Greenfield filter (Group B = 10 patients). Seventy-five percent (15/20) of the Group A patients developed 19 bleeding or thrombosis-related complications: major bleeding (7), recurrent deep venous thrombosis/pulmonary embolism (4), inability to attain consistent therapeutic anticoagulation levels (3), heparin-induced thrombocytopenia (3), or progression of deep vein thrombosis (2). A Greenfield filter was eventually placed in 10 (50%) of the Group A patients without complications. Thirty percent (3/10) of the Group B patients developed progression of deep vein thrombosis that required anticoagulation. One other Group B patient died due to a guidewire-induced arrhythmia. Although patients with advanced cancers and venous thromboembolic disease have a high complication rate with either treatment, initial treatment with a Greenfield filter appears more definitive. Anticoagulation should be reserved for patients with progressive, symptomatic deep vein thromboses after placement of a filter.