Mortality risk after cancer-related venous thromboembolism has decreased over the last three decades: the HUNT and Tromsø studies

Abstract

Venous thromboembolism (VTE) is a common and serious condition among cancer patients. The diagnostic and therapeutic strategies for cancer and VTE have improved during the last three decades. It remains unclear whether mortality after cancer-related VTE (CRVTE) has decreased in this period. Therefore, we investigated the mortality risk after CRVTE over the last three decades in a population-based cohort. In total, 111,119 participants from Tromsø4-7 (1994-2016) and HUNT2-3 (1995-2008) surveys were followed through 2019, and all firstlifetime cancer and VTE events were recorded. CRVTE patients were compared with participants neither exposed to cancer nor VTE (disease-free-group), and those with cancer. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for all-cause mortality using Cox regression with cancer and VTE as time-dependent exposures, and one-year cumulative incidence of mortality after CRVTE. Analyses were performed for three timeperiods (1994-2002, 2003-2011, 2012-2019). The age- and sex-adjusted HRs for mortality after CRVTE versus disease-free-group decreased from 25.3 (95%CI 20.5-31.3) in 1994-2002 to 22.6 (95%CI 19.2-26.6) in 2003-2011, and 16.9 (95%CI 14.3-20.0) in 2012-2019. The HRs for mortality after CRVTE versus cancer-group remained stable (about 3-fold higher) along the three time-periods. Similar estimates were obtained after further adjustments for comorbidities. The one-year cumulative incidence of mortality after CRVTE decreased from 61.8% (95%CI 52.9%-70.8%) in 1994-2002 to 55.6% (95%CI 49.0%-62.4%) in 2003-2011, and 45.5% (95%CI 39.3%-52.1%) in 2012-2019. Our results indicate a decrease in mortality risk after CRVTE over the last three decades, which might be mainly the result of considerable advances in cancer management.