Metachronous and Synchronous Cancers in Patients with Neuroendocrine Tumors

Introduction: Neuroendocrine tumors (NETs) are a heterogeneous group of malignancies with various clinical presentations and growth rates. NET incidence has been estimated to 2.5–5 per 100,000 people per year, and NET prevalence is 35 per 100,000. They are frequently associated with synchronous or metachronous second primary malignancies (SPM). Methods: We retrospectively reviewed our institutional database on NET patients. We report on 30 patients with NETs and SPMs from a series of 262 patients with NETs: 10 patients with synchronous NETs (33.3%) and 20 with metachronous SPMs (66.6%). Results: The median patient age was 67 years. Of the 10 synchronous lesions, 50% were observed in the GI tract. The most common locations of these lesions were the colon (15%) and pancreas (25%). In 2 patients, there was an association of prostate neoplasia with a subsequent NET of the pancreas. Conclusions: Only few studies have examined the association between NETs and SPMs. Our study showed that the risk of second cancer following NETs is increased. In this single-institution retrospective review, our incidence of additional malignancies in patients with NET was 11.4%.