The following is a summary of “Clinical Presentation and Outcomes of Patients With Cancer-Associated Isolated Distal Deep Vein Thrombosis,” published in the February 2024 issue of Oncology by Galanaud, et al.

Patients with isolated distal deep vein thrombosis (DVT) typically experience lower rates of adverse outcomes compared to those with proximal DVT. However, it remained uncertain whether these findings apply to patients with cancer.

Utilizing data from the international Registro Informatizado de la Enfermedad TromboEmbolica venosa registry, researchers conducted a comparative analysis of adverse outcomes at 90 days (adjusted odds ratio [aOR]; 95% CI) and 1 year (adjusted hazard ratio [aHR; 95% CI]) in three cohorts: 886 patients with cancer-associated distal DVT, 5,196 patients with cancer-associated proximal DVT, and 5,974 patients with non-cancer-associated distal DVT.

Over 90% of patients in each group received anticoagulant treatment for at least 90 days. At 90 days, patients with non-cancer-associated distal DVT exhibited lower adjusted risks of death, VTE recurrence, or major bleeding compared to those with cancer-associated distal DVT (reference): aOR = 0.16 (0.11-0.22), aOR = 0.34 (0.22-0.54), and aOR = 0.47 (0.27-0.80), respectively. Similar results were observed at 1-year follow-up: aHR = 0.12 (0.09-0.15), aHR = 0.39 (0.28-0.55), and aHR = 0.51 (0.32-0.82), respectively. However, there were no statistically significant differences in the risks of death, VTE recurrence, or major bleeding between patients with cancer-associated proximal versus distal DVT, both at 90 days and 1 year. Notably, more patients with cancer-associated proximal DVT experienced fatal pulmonary embolism (PE) during follow-up compared to those with cancer-associated distal DVT: The risk difference was 0.40% (95% CI, 0.23 to 0.58).

Cancer-associated distal DVT presents serious and relatively comparable outcomes to cancer-associated proximal DVT. However, the lower risk of fatal PE associated with cancer-associated distal DVT warranted further investigation.

Reference: ascopubs.org/doi/10.1200/JCO.23.00429