Risk and prognosis of cancer after upper-extremity deep venous thrombosis: A population-based cohort study.

INTRODUCTION: The association between lower-extremity venous thrombosis and cancer is well-established. However, the extent to which upper-extremity deep venous thrombosis (U-DVT) is a marker of cancer and a prognostic factor for all-cause mortality remains poorly understood. We examined the risk of cancer after a diagnosis of U-DVT compared with cancer risk in the general population.

MATERIALS AND METHODS: Using Danish nationwide population-based medical registries, we identified all patients with first-time U-DVT during 1980-1993 and 2000-2013. Cancer incidence was ascertained using data from the Danish Cancer Registry. We computed standardized incidence ratios (SIRs) calculated as the observed number of cancers relative to the expected number based on national incidence rates by sex, age, and calendar year. We created a matched comparison cohort of cancer patients without U-DVT, to assess the impact of U-DVT on all-cause mortality.

RESULTS: Among 1087 patients with U-DVT, 232 patients subsequently were diagnosed with cancer, corresponding to an overall SIR of 1.69 (95% confidence interval, 1.48-1.92). During the first 6months following U-DVT, the absolute risk of any cancer was 5.4%, corresponding to a 13-fold elevated SIR. During the subsequent 6-12months and >12months, the SIR remained 2-fold and 1.3-fold elevated, respectively. U-DVT was a prognostic factor for all-cause mortality in patients with lung, prostate, and colorectal cancer during the first 6months of follow-up.

CONCLUSION: U-DVT was a marker of cancer. The clinical utility of searching for occult cancer in patients with U-DVT remains unknown.