Alkaline phosphatase predicts survival in patients with metastatic neuroendocrine tumors

The clinical course of patients with metastatic neuroendocrine tumors is highly variable. While some patients experience an indolent clinical course over many years, other patients may rapidly succumb to their disease. Little is known about prognostic factors in these patients, making decisions regarding their management more difficult. We performed a retrospective analysis of 137 patients with metastatic neuroendocrine tumors referred to our institution for treatment. Potential prognostic factors were evaluated using multivariate survival analysis. The median overall survival of patients in our cohort was 6.0 years, although the range of survival times was broad (48 days to 23.4 years). Alkaline phosphatase levels above normal were predictive of shorter survival in both univariate and multivariate analysis. Elevated chromogranin A levels were also associated with shorter survival in univariate analysis; in a multivariate analysis, however, this correlation was no longer significant. There was no association between survival and gender, primary tumor site, or presence or absence of carcinoid syndrome. Elevated alkaline phosphatase is a robust adverse prognostic factor for survival in patients with metastatic neuroendocrine tumors and may be superior to chromogranin A in this setting. Close monitoring of alkaline phosphatase levels may be useful when considering initiation or changes of therapy in patients with metastatic neuroendocrine tumors.