ANTIPHOSPHOLIPID ANTIBODIES IN CANCER PATIENTS WITH VENOUS THROMBOSIS

Background: Venous thrombosis is a frequent and severe event in patients with cancer. Antiphospholipid antibodies (aPL) have been associated with thrombotic events in the context of the antiphospholipid syndrome (APS), but they have been reported with varying frequency in patients with malignancies.Objectives: Our aim was to determine the prevalence of aPL in an unselected group of cancer patients with and without thrombosis.Methods: Patients with cancer seen in the Medical Oncology Department were enrolled in this study. We also analyzed a control group of 120 healthy individuals, age and gender matched, without autoimmune disease, bleeding disorders, thrombosis, or a history of pregnancy loss. All thrombotic events were assessed clinically and confirmed by objective methods. Antiphospholipid antibodies tests were performed. Lupus anticoagulant (LA) was determined following the guidelines of the Subcommittee for the Standardization of Lupus Anticoagulants of the International Society of Thrombosis and Hemostasis. Anticardiolipin antibodies (aCL) were measured using a standardized enzyme-linked immunosorbent assay (Cheshire Diagnostics, Chester, UK). Results were expressed in IgG and IgM units (GPL and MPL) and reported as negative (<15 units), low positive (16–25 units), moderate positive (26–40 units), and high positive (>40 units).Results: Two hundred and forty-one patients (137 males and 104 females; mean age of 61.8±11.8 years) were recruited: 190 presented with thrombosis and 51 without thrombosis. There were no differences between the two groups in the distribution by gender, mean age and the location of cancer, being the most frequents the lung (25.7%), colon (19.1%) and breast (13.7%).Deep venous thrombosis involved the lower limbs in 115 (60.5%) patients, upper extremities in 25 (13.2%), superior vena cava in 4 (2.1%), inferior vena cava in 3 (1.6%), and cerebral venous sinus and visceral thrombosis (two cases each one). Pulmonary embolism occurred in 59 (31%) patients. Superficial venous thrombosis occurred in 4 (2.1%) patients. Nine (4.7%) patients suffered from an episode of previous thrombosis. Predisposing clinical factors to thrombosis were present in 86 (45.3%) patients, including immobilization in 53 (27.9%), post-operative state in 30 (15.8%), and intravenous catheter in 24 (12.7%) patients.The prevalence of aPL in cancer patients with thrombosis was significantly elevated compared with cancer patients without thrombosis and with healthy individuals (10% vs 0% vs 0%; p<0.005). LA was detected in 9 (4.7%) patients, and the aCL titer was positive in 11 (5.8%). All patients were positive for the IgG aCL (3 at low titers, 4 at moderate, and 4 of them showed titers >40 UGPL). No one had positivity for the IgM isotype. No differences in the prevalence of predisposing clinical factors to thrombosis were detected between two groups. Only one of these aPL +ve patients had a history of previous thrombosis (he had both persistently LA and aCL positivity).Conclusion: Compared with cancer patients without thrombosis and healthy individuals, cancer patients with thrombosis had an elevated prevalence of aPL. The presence of aPL may identify a subset of cancer patients who are at high risk of developing thrombotic complications.References: Zuckerman E, Toubi E, Golan TD, et al. Increased thromboembolic incidence in anti-cardiolipin-positive patients with malignancy. Br J Cancer 1995;72:447-51.Reinstein E, Shoenfeld Y. Antiphospholipid Syndrome and Cancer. Clin Rev Allergy Immunol 2007;32:184-7.Citation: Ann Rheum Dis, volume 67, supplement II, year 2008, page 216Session: SLE, Sjögren's and APS – Clinical aspects and treatment