A clinical outcome-based prospective study on venous thromboembolism in cancer surgery: the @RISTOS project

Abstract number: OC191

Agnelli^* G., Bolis† G., Capussotti‡ L., Scarpa§ R. M., Tonelli¶ F., Bonizzoni† E., Moia† M., Rossi^** R., Sonaglia^** F., Valarani†† B., Bianchini‡‡ C., Gussoni§§ G.

^*Division of Internal and Cardiovascular Medicine, Italy; ¶Florence, Italy; ††Hyperphar Reseach, Milan, Italy; ‡‡Italy; †Milan, Italy; §Orbassano, Turin, Italy; ^**Perugia, Italy; §§Scientific Department, Italfarmaco, Milan, Italy ‡Turin, Italy;

Background  

The epidemiology of venous thromboembolism (VTE) after cancer surgery is essentially based on venography clinical trials on VTE prophylaxis. However, the clinical relevance of asymptomatic venography-detected deep vein thrombosis (DVT) is unclear and the study population of these clinical trials is not necessarily representative of the overall cancer surgery population, since study patients are selected by strict inclusion and exclusion criteria.

Aim of the study  

To evaluate the incidence of clinically overt VTE in a wide-spectrum of consecutive patients undergoing surgery for cancer and to identify potential risk factors for VTE.

Methods  

@RISTOS was a prospective registry including consecutive patients undergoing abdominal, thoracic, urologic or gynecologic surgery for cancer. Patients were assessed for clinically overt VTE occurring during the in-hospital stay and in the 30±5 days after surgery. All outcome events were evaluated by an external independent adjudication committee. An electronic web-based system was used for data collection.

Results  

From November 2000 to October 2001, 2373 patients were included in the study in 31 Italian hospitals: 1238 (52%) undergoing general surgery, 685 (29%) urologic surgery, and 450 (19%) gynecologic surgery. A follow-up as scheduled by study protocol was obtained in 99.5% of patients. In-hospital prophylaxis was performed in 81.6% and postdischarge prophylaxis in 30.7% of the patients. The overall death rate was 1.72%, in 46.3% of the cases due to VTE. Fifty patients (2.1%) were adjudicated as affected by clinically overt VTE by the adjudication committee (DVT 0.42%, non fatal pulmonary embolism 0.88% and death 0.80%). The incidence of VTE was 2.83% in general surgery, 2.0% in gynecology surgery and 0.87% in urology surgery. Forty percent of the events occurred >21 days after surgery. In a multivariate logistic regression analysis five risk factors were identified: age >60 years (OR 2.63, 95% CI 1.21–5.71), previous VTE (OR 5.98, 2.13–16.80), advanced cancer (OR 2.68, 1.37–5.24), duration of anesthesia > 2 h (OR 4.50, 1.06–19.04) and bed resting >3 days (OR 4.37, 2.45–7.78).

Conclusions  

Despite a widespread use of thromboprophylaxis, VTE is still the most common cause of death after oncology surgery, with a remarkable proportion of clinically overt VTE events occurring late after surgery. Further efforts should be done to optimize prophylaxis in patients undergoing cancer surgery.