GROWTH OF NEWLY-DIAGNOSED, UNTREATED METASTATIC GASTRINOMAS AND PREDICTORS OF GROWTH-PATTERNS

Purpose: The growth pattern of untreated metastatic neuroendocrine tum ors is unknown, This uncertainty contributes to the disagreement regar ding timing and could effect evaluation of the efficacy of antitumor t reatment, The purpose of this study was to determine the growth rate o f untreated hepatic metastatic gastrinoma and to identify its predicto rs, Patients and Methods: Nineteen patients with histologically proven metastatic gastrinoma in the liver with Zollinger-Ellison syndrome we re studied, Conventional imaging studies were performed initially and at 4- to 6-month intervals before any treatment, Metastases growth rat es were calculated and correlated with laboratory and clinical paramet ers, as well as tumor extent on initial tumor assessment, Results: Twe nty-six percent of patients (five of 19) demonstrated no growth over a mean follow-up time of 29 months, 32% (six of 19) had slow growth (1% to 50% increase in volume per month) over a 19-month period, and 42% (eight of 19) had rapid growth (> 50% volume increase per month) over an 11-month period, In patients with rapid growth, 62% died; 0% of the no-growth or slow-growth group died, No clinical or laboratory parame ter correlated with growth rate, except the rate increase in fasting s erum gastrin and the presence of bilobar liver or bone metastases, The growth rate was highly predictive of death from tumor, Conclusion: Th e growth rate of metastatic gastrinoma varies markedly in different pa tients and 26% demonstrated no growth, The growth rate needs to consid ered in the determination of when and in whom antitumor therapy is ini tiated, as well us in the assessment of response to tumoricidal therap ies.