918P - A pooled data analysis of 12 clinical trials of Fondazione Italiana Linfomi (FIL): Khorana score and histotype predict the incidence of early venous thromboembolism (VTE) in non-Hodgkin lymphoma (NHL)

Abstract

VTE in NHL occurs in most cases within 3 months from diagnosis and can have substantial impact on treatment delivery and outcome. However, few data are available on potential predictors. We conducted a pooled data analysis of 12 clinical trials from FIL. Our analysis included basic demographic features, lymphoma-related characteristics as well the Khorana score (based on histology, BMI, platelets WBC and HB counts) which is extensively used in solid tumors to predict VTE risk. From Jan. 2010 to Dec. 2014, all pts with B-cell NHL enrolled in prospective clinical trials from FIL for frontline treatment were included. The analyses were conducted based on CRFs as well as pharmacovigilance reports. Cumulative incidence of VTE from the study enrollment was estimated using the method described by Gooley et al. accounting for death from any causes as a competing risk. The Fine & Gray survival model was used to identify predictors of VTE among NHL pts. Factors predicting the grade of VTE were investigated using an ordinal logistic regression model. Overall, 1717 patients belonging to 12 studies were evaluated. M/F ratio was 1.41, median age was 57. Histologies were: DLCL-B 34%, FL 41%, MCL 18%, other 6%. Median BMI was 25. Median Hb, WBC and platelets counts were : 13 g/dl, 7,1 x 109/l, 224 x 109/l, respectively. Overall 59 any grade VTE episodes occurred in 51 pts (2.9%). None was fatal. Median time from study enrolment to VTE was 63 days . Considering death as a competitive event the 6 months cumulative incidence of VTE was 2.2% in low risk Khorana score, 4.5% in intermediate and 6.6% in high risk (p = 0.012) . The Fine and Gray multivariate analyses, adjusted for age and stage, showed that Khorana score and DLCL-B histotype were independently associated to an increased risk of VTE. Moreover an ordinal logistical regression model indicated that the increase of one point in the Khorana score resulted in an increased risk of VTE. Our results suggest that DLCL-B histotype and Khorana score are predictors of VTE in NHL. The latter might become a simple and effective tool to assess the risk of VTE in NHL.