Prevalence of cancer in patients with superficial vein thrombosis and its clinical importance.

OBJECTIVE: The objective of the present study was to evaluate the prevalence of cancer in patients with superficial vein thrombosis (SVT) of the legs. Moreover, we evaluated the potential determinants of SVT complications by comparing a subgroup with isolated SVT and a subgroup of SVT complicated by concurrent deep vein thrombosis (DVT) and/or pulmonary embolism (PE) with respect to the presence of cancer and other clinical and laboratory characteristics. METHODS: The present single-center, retrospective study of prospectively collected data was conducted in a tertiary care setting. We included patients who had been treated in the thrombosis clinic from 2006 to 2018 for symptomatic SVT of the legs, either isolated SVT or SVT complicated by concurrent DVT/PE. We evaluated the prevalence and type of malignancy (diagnosed ≤12 months before SVT and/or ongoing therapy), demographics, and clinical and laboratory characteristics of the patients. For statistical evaluation, we used the Student t test, Kruskal-Wallis test, Fisher exact two-sided test, and logistic regression. RESULTS: Of 276 patients with SVT (mean age, 58.9 ± 14.7 years; 60.9% women), 191 had had isolated SVT and 85 had had SVT complicated by concurrent DVT/PE. The prevalence of malignancy was 8.7% in the whole group (mainly breast and urinary tract cancer), including 4.2% of those with isolated SVT and 18.8% of those with SVT and concurrent DVT/PE (P < .001). Between the two subgroups, no significant differences were present in the duration of leg symptoms, family or personal history of SVT and/or DVT, SVT location, and smoking. In logistic regression, several factors were significantly associated with the concurrent presence of DVT/PE: age (odds ratio [OR], 1.024; 95% confidence interval [CI], 1.004-1.044), female gender (OR, 0.545; 95% CI, 0.309-0.960), varicose vein SVT (OR, 0.42; 95% CI, 0.194-0.902), thrombophilia (OR, 1.939; 95% CI, 1.089-3.454), and cancer (OR, 4.727; 95% CI, 1.814-12.316). CONCLUSIONS: The prevalence of malignancy in the patients with SVT was 8.7%. Age, thrombophilia, male gender, nonvaricose vein SVT, and cancer were significantly associated with the presence of concurrent DVT/PE. Cancer was the strongest determinant of concurrent DVT/PE.