GRADE OF MALIGNANCY AND PROGNOSIS OF WELL-DIFFERENTIATEDNEUROENDOCRINE TUMORS OF THE GASTROINTESTINAL TRACT

V.V. Delektorskaya, N.A. Kozlov, G.Yu. Chemeris
N.N. Blokhin Russian Cancer Research Center, Moscow

To study the correlation of proliferative activity of tumor cells with clinical and morphological parameters and indices of survival rates a retrospective clinical and morphological analysis of 60 cases of localized and metastatic neuroendocrine tumors (NETs) of the various parts of the gastrointestinal tract is presented. Ki67 expression was evaluated in primary tumors and their metastases in the lymph nodes and liver. Morphological features of different types of tumors, including NET G1 and NET G2, as well as the rare group of NET G3. As a result of the study it was shown that the proliferative activity in the secondary foci of tumor growth may increase during tumor progression in 1,5–4,5 times in comparison with the primary tumor. Significant interrelationship was found between indices of proliferative activity (expression of Ki67) and the incidence of the development of distant metastases, the size of the primary tumor and survival rate of patients with gastrointestinal NETs. Thus, proliferation index (expression of Ki67) is a key parameter of the morphological diagnostics of gastrointestinal NETs. The estimation of Ki67 proliferation index in the each site of the locations of the tumor process is critical for accurate determination of the grade of malignancy, prognosis, and features of treatment of metastatic tumors.
Keywords: 
neuroendocrine tumors of the gastrointestinal tract, proliferative activity, the grade of malignity, the prognosis