Idiopathic Superficial Thrombophlebitis and the Incidence of Cancer in Primary Care Patients

PURPOSE The association of spontaneous venous thromboembolism with occult malignancy is well established. Less clear is the incidence of subsequent cancer in patients with superfi cial thrombophlebitis. We wanted to determine the incidence of cancer after an episode of spontaneous superfi cial thrombophlebitis in a large general practice population. METHODS The objective of this study was to assess the incidence of newly diag- nosed malignancies in patients within 2 years after the diagnosis of a spontane- ous episode of superfi cial thrombophlebitis and to compare this incidence with nonexposed matched control patients and the Dutch population. The patients and their controls were identifi ed by a search in the electronic patient records of 5 primary health care centers in Amsterdam, the Netherlands. A standardized morbidity ratio was calculated using data of the Dutch cancer registry. RESULTS A total number of 277 patients with superfi cial thrombophlebitis were identifi ed, of which 250 patients had no cancer at study entry. In 5 of these 250 patients (2%; 95% confi dence interval (CI), 1%-5%), a new malignancy was diagnosed within 2 years after their superfi cial thrombophlebitis compared with 2% (95% CI, 1%-4%) in the control group. The standardized morbidity ratio was 1.1 (95% CI, 0.5-2.7). A recurrent episode of superfi cial thrombophlebitis was observed in 18 of the 250 patients, and in 1 patient cancer was diagnosed within 24 months after the fi rst episode of superfi cial thrombophlebitis. CONCLUSION We conclude that a single episode of unprovoked superfi cial thrombophlebitis diagnosed by a family physician is not associated with an increased risk of subsequent cancer.