Clinical validation of the gastrointestinal NET grading system: Ki67 index criteria of the WHO 2010 classification is appropriate to predict metastasis or recurrence

Abstract

BackgroundIn the WHO 2010 classification, the neuroendocrine tumors (NETs) are subdivided by their mitotic index or Ki67 index into either G1 or G2 NETs. Tumors with a Ki67 index of <2% are classified as G1 and those with 3—20% are classified as G2. However, the assessment of tumors with Ki67 index of greater than 2% and less than or equal to 3% is still unclear. To resolve the problem, we validated the Ki67 index criteria of gastrointestinal NETs of the WHO 2010 classification.MethodsThe medical records of 45 patients who were pathologically diagnosed as having NET G1/G2 of the gastrointestinal tract were analyzed retrospectively. According to the WHO 2010 classification, Ki67 index were calculated. Computer-assisted cytometrical analysis of Ki67 immunoreactivity was performed using the WinRooF image processing software. Receiver operating characteristic (ROC) curves were generated to determine the best discriminating Ki67 index. To clarify the assessment of tumors with Ki67 index between 2—3%, the calculated cutoff of Ki67 index was evaluated using Fisher’s exact test.ResultsROC curve analysis confirmed that 2.8% was the best Ki67 index cutoff value for predicting metastasis or recurrence. The sensitivity of the new Ki67 index cutoff was 42.9%, and the specificity was 86.8%.ConclusionsDivision of NETs into G1/G2 based on Ki67 index of 3% was appropriate to predict metastases or recurrences. The WHO grading system may be the most useful classification to predict metastases or recurrences.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1553036118943799

Evaluation of treatment for rectal neuroendocrine tumors sized under 20 mm in comparison with the WHO 2010 guidelines

“…However, none of our patients with G1/G2 and G2 NETs had lymph node metastasis (22). Only 1 of 12 (8.3%) patients had lymphatic or venous invasion, which is a low rate compared with that of other reports.…”

Comparative diagnostic and prognostic performances of the hematoxylin-eosin and phospho-histone H3 mitotic count and Ki-67 index in adrenocortical carcinoma

“…8,57 Therefore, we additionally compared phospho-histone H3 data with Ki-67 values and found a very high correlation, with special reference to phospho-histone H3 manual counting. The impact of Ki-67 determination at the diagnostic level is however not well established in adrenocortical carcinoma, and from a practical point of view the value of this observation is limited.…”

Pancreatic neuroendocrine tumors: correlation between histogram analysis of apparent diffusion coefficient maps and tumor grade

“…Studies have shown the usefulness of this grading system, as some of the well-differentiated tumors with higher proliferative index (G2) seem to have worse prognosis than PanNET with lower proliferative index (G1) [6,7]. It has been shown that this grading system is a valid tool for progCorrespondence to: Jose Antonio Sousa Pereira; email: pereirajoseantonio@outlook.com nostic stratification in clinical practice and research [8,9]. The choice of treatment depends not only on the symptoms, stage of disease, degree of uptake of radionuclide but also on tumor grade [10].…”