Second primary malignancies in patients with neuroendocrine tumors

An association between neuroendocrine tumors (NETs) and second primary malignancies (SPMs) has been reported. We have examined the incidence and etiology of SPMs in patients with NETs included in the Neuroendocrine Tumor Association of Andalusia (ATNEA) Registry.

Data on 111 patients were collected. Sex, age, NET site, chromogranin A levels, neuropeptide secretion and disease stage were compared between NETs with and without SPMs.

SPMs were present in 21 patients (18.9 %): five colorectal tumors, four non-small-cell lung cancers, three gastric cancers, two tumors in the small intestine, one hepatocarcinoma, two ovarian tumors, one breast adenocarcinoma, one hypernephroma, one bladder cancer, and one neuroblastoma. SPMs were present in 18 % of patients with a gastrointestinal NET and 22 % of those with a non-gastrointestinal NET. SPMs were found in 23 % of patients with elevated levels of serum chromogranin A, compared to 17 % of patients with normal levels, and in 22 % of patients with functional tumors, compared to 11 % of those with non-functional tumors. Finally, SPMs were observed in 24 % of patients with a local or locoregional tumor but in only 13 % of those with a metastatic tumor. No other differences between patients with and without SPMs were observed.

The percentage of patients with SPMs in the ATNEA Registry is similar to those reported in other series. In our registry, patients with functional NETs and local/locoregional tumors have higher probability of SPMs. The low number of patients, selection bias and other etiologic factors of SPMs may have influenced our results.