Thrombosis and Haemostasis 103.2/2010 338 © Schattauer 2010 Blood Coagulation, Fibrinolysis and Cellular Haemostasis Frequency, demographics and risk (according to tumour type or site) of cancer-associated thrombosis among patients seen at outpatient DVT clinics Shankaranarayana Paneesha 1 ; Aidan McManus 2 ; Roopen Arya 3 ; Nicholas Scriven 4 ; Timothy Farren 5 ; Tim Nokes 6 ; Sue Bacon 7 ; Anthea Nieland 8 ; Derek Cooper 9 ; Harry Smith 10 ; Denise O'Shaughnessy 11 ; Peter Rose 12 ; for the VERITY Investigators 1 Consultant, Department of Haematology, Heart of England NHS Foundation Trust, Birmingham, UK; 2 Director, MMRx Consulting, Cheam, Surrey, UK; 3 Consultant, Department of Haematology, King's College Hospital, London, UK; 4 Consultant, Medical Assessment Unit, The Calderdale Royal Hospital, Halifax, UK; 5 Clinical Scientist, Department of Haematology, Barts and The London School of Medicine and Dentistry, London, UK; 6 Consultant, Department of Haematology, Derriford Hospital, Plymouth, UK; 7 Thrombosis Nurse Specialist, Scarborough Hospital, Scarborough, UK; 8 Thrombosis Nurse Specialist, Northampton General Hospital NHS Trust, Northampton, UK; 9 Statistical Consultant, London, UK; 10 Harry Smith, Medical Advisor, Sanofi Aventis UK*; 11 Special Advisor, Blood Policy Unit, Department of Health, London, UK; 12 Consultant, Department of Haematology, Warwick Hospital, Warwick, UK Summary Venous thromboembolism (VTE) is a clinically important complication for both hospitalised and ambulatory cancer patients. In the current study, the frequency, demographics and risk (according to tumour site) of VTE were examined among patients seen at outpatient DVT (deep- vein thrombosis) clinics. Of 10,015 VTE cases, 1,361 were diagnosed with cancer, for an overall rate of cancer-associated VTE of 13.6% in this outpatient population. Patients with cancer-associated VTE were sig- nificantly older than cancer-free VTE cases (66.4 ± 12.7 vs. 58.8 ± 18.5 years; p<0.0001). The frequency of cancer-associated VTE peaked ear- lier among females than males, occurring in the sixth (137/639, 21.4% vs. 98/851, 11.3%; p<0.001) and seventh decades (213/980, 21.7% vs. 197/1096, 18%; p=0.036). VTE was described most frequently in com- mon cancers – breast, prostate, colorectal and lung (56.1% of cases). The risk of VTE varied widely across 17 cancer types. Calculating odds Correspondence to: Dr. Peter Rose Consultant Haematologist, Department of Haematology Warwick Hospital, Warwick, CV34 5BW, UK Tel.: +44 1926 495321, ext. 4209 E-mail: Peter.Rose@swh.nhs.uk ratios (OR) to assess the effect size of cancer type on VTE risk, the high- est odds were observed for patients with pancreatic cancer (OR 9.65, 95% confidence interval [CI] (5.51–16.91). Tumours of the head and neck had higher odds than previously reported (OR 8.24, 95% CI 5.06–13.42). Reduced risk estimates were observed for skin cancers (melanoma and non-melanoma: OR 0.89, 95% CI 0.42–1.87; OR 0.74, 95% CI, 0.32–1.69, respectively). We conclude that outpatients have a similar rate of cancer-associated VTE as VTE patient populations pre- viously reported, that cancer-associated VTE occurs in an older age group and earlier in females and that outpatients exhibit distinct tu- mour site-specific risk from that described among hospitalised cancer patients. Keywords Clinical studies, cancer, venous thrombosis Financial support: The VERITY registry is funded by sanofi-aventis. Received: June 24, 2009 Accepted after major revision: October 26, 2009 Prepublished online: December 18, 2009 doi:10.1160/TH09-06-0397 Thromb Haemost 2010; 103: 338–343 * Current position: Medical Manager, Pfizer, Walton-On-The-Hill, Surrey, UK. Introduction Venous thromboembolism (VTE) is a clinically relevant disease in cancer patients (1), with recent studies suggesting it is becoming more frequent (2). Large studies have shown that clinically appar- ent VTE is associated with worse mortality in cancer patients than non-cancer patients. In hospitalised cancer patients undergoing potentially curative surgery, fatal pulmonary embolism (PE) de- tected at autopsy was three-fold higher than in patients without cancer undergoing surgery at the same sites (3). A Dutch cancer registry that matched cancer patients with and without VTE showed a 2.2-fold mortality increase in those with cancer-associ- ated VTE (4). More recently, a study of ambulatory cancer patients beginning chemotherapy showed that thromboembolism (includ- ing arterial events) was a leading cause of death, accounting for up to 9% of mortality (5). The distinction between hospitalised cancer patients and those patients receiving outpatient care is important when considering thrombosis risk and prevention. The benefit of heparin-based thromboprophylaxis has been proven in selected cancer surgery in- patients (6), but this is not the case for cancer outpatients with meta- static breast or lung cancer (7), or for those patients with intravenous catheters (8), for whom clinical trials of low-molecular-weight hepa- rin (LMWH) showed no benefit. These findings are reflected in cur- rent guidelines that do not recommend thromboprophylaxis in cancer outpatients (9, 10). This suggests that high-risk populations have not been accurately identified and that a greater understanding is required of cancer-associated thrombosis in outpatients to ident-