Association of VEGF expression with poor prognosis among patients with low-grade neuroendocrine carcinoma

Abstract

4091 Background: Low-grade neuroendocrine carcinomas (LGNET) can arise from neuroendocrine cells throughout the body and have a wide range of aggressiveness. Reliable predictive and prognostic markers of outcome are lacking. Angiogenesis is critical for metastasis and tumor growth beyond a small tumor size and VEGF is a powerful mediator of tumor angiogenesis. Methods: LGNET tissue from 50 patients (24 with local-regional disease, 26 with metastasis) who underwent tumor resection at the University of Texas M.D. Anderson Cancer Center was evaluated for expression VEGF by immunohistochemistry. Chi-square and Fisher’s exact test were used to test the association between study parameters. Kaplan-Meier analysis was used to assess the affect of study parameters on progression free survival (PFS). Results: Strong, weak, and negative VEGF expression was observed in 32%, 54%, and 14% of cases respectively. Larger tumor size was observed among patients with strong VEGF expression. Mean tumor sizes in patients with strong, weak and negative VEGF were 4.8, 2.8, and 2.9 cm. Compared to the group with negative VEGF expression, VEGF (weak/strong) expression was associated with metastasis (14% v 58%; P = .045). The median PFS durations of patients with strong and weak VEGF expression were 29 months and 81 months respectively. With a median follow-up duration of 50 months, the median PFS duration for the group with negative VEGF expression has not been reached. Compared by log rank test VEGF expression was associated with poor PFS (P = .022). Conclusions: This study suggests that tissue VEGF expression is associated with aggressive tumor growth and metastasis among patients with LGNET. VEGF expression may serve as a useful prognostic marker following tumor resection. No significant financial relationships to disclose.