Long‐term outcomes of cancer‐related isolated distal deep vein thrombosis: the OPTIMEV study

Essentials Clinical significance of cancer-related isolated distal deep vein thrombosis (iDDVT) is unknown. We studied patients with iDDVT, with and without cancer, and proximal DVT with cancer. Cancer-related iDDVT patients have a much poorer prognosis than iDDVT patients without cancer. Cancer-related iDDVT patients have a similar prognosis to cancer-related proximal DVT patients. SummaryBackground Isolated distal deep vein thrombosis (iDDVT) (infra-popliteal DVT without pulmonary embolism [PE]) is a frequent event and, in the absence of cancer, is usually considered to be a minor form of venous thromboembolism (VTE). However, the clinical significance of cancer-related iDDVT is unknown. Methods Using data from the observational, prospective multicenter OPTIMEV cohort, we compared, at 3 years, the incidences of death, VTE recurrence and major bleeding in patients with cancer-related iDDVT with those in cancer patients with isolated proximal DVT (matched 1:1 on age and sex) and patients with iDDVT without cancer (matched 1:2 on age and sex). Results As compared with patients with cancer-related isolated proximal DVT (n = 92), those with cancer-related iDDVT (n = 92) had a similar risk of death (40.8% per patient-year (PY) vs. 38.3% per PY; aHR = 1.0, 95% CI[0.7–1.4]) and of major bleeding (3.8% per PY vs. 3.6% per PY, aCHR = 0.9 [0.3–3.2]) and a higher risk of VTE recurrence (5.4% per PY vs. 11.5% per PY; aCHR = 1.8 [0.7–4.5]). As compared with patients with iDDVT without cancer (n = 184), those with cancer-related iDDVT had a nine times higher risk of death (3.5% per PY vs. 38.3% per PY; aHR = 9.3 [5.5–15.9]), a higher risk of major bleeding (1.8% per PY vs. 3.6% per PY; aCHR = 2.0 [0.6–6.1]) and a higher risk of VTE recurrence (5.0% per PY vs. 11.5% per PY; aCHR = 2.0 [1.0–3.7]). The results remained similar in the subgroup of patients without history of VTE. Conclusion Patients with cancer-related iDDVT seem to have a prognosis that is similar to that of patients with cancer-related isolated proximal DVT and a dramatically poorer prognosis than patients with iDDVT without cancer. This underlines the high clinical significance of cancer-related iDDVT and the need for additional studies.