The Novel WHO 2010 Classification for Gastrointestinal Neuroendocrine Tumours Correlates Well with the Metastatic Potential of Rectal Neuroendocrine Tumours

Abstract

Background: Approximately 10–15% of gastroenteropancreatic neuroendocrine tumours (NETs, carcinoids) occur in the rectum, some of which are potentially able to metastasize. The new WHO 2010 classification of NETs applies to all gastroenteropancreatic NETs, but no reports have studied its correlation with the prognosis of rectal NETs. Patients and Methods: We retrospectively classified 73 rectal NETs according to the novel WHO 2010 and the previous WHO 2000 classifications. The aim was to assess the validity of the classifications in distinguishing indolent rectal NETs from metastasising tumours. Results: Using the WHO 2010 criteria, we identified 61 G1 tumours, none of which had metastasised during follow-up. Of 11 G2 tumours, 9 had shown distant metastases. The only G3 neuroendocrine carcinoma that occurred had been disseminated at initial presentation. Conclusion: Our results show that rectal NETs classified as G1 according to the WHO 2010 classification have an indolent clinical course, whereas G2 NETs often metastasise. The WHO 2010 classification of NETs predicts the metastatic potential of rectal NETs better than the WHO 2000 classification.

Comparison of WHO 2000 and WHO 2010 classifications of gastroenteropancreatic neuroendocrine tumors

“…G3, on the other hand, is a small-cell and large-cell neoplasm subtype (6)(7)(8). In a study of Jernman et al (15) classification was found to be more beneficial in predicting the potential of metastasis of the neuroendocrine tumors compared to the WHO 2000 classification. In a study of Endo et al (16) in 22 gastric neuroendocrine tumors, 81 cases were G1, 5 were G2, and 16 were NEC.…”

Sex comb on midleg like-2 is a novel specific marker for the diagnosis of gastroenteropancreatic neuroendocrine tumors

“…A total of 64 paired tumor tissues and adjacent non-tumorous tissues were obtained from paraffin-embedded tissues of patients with GEP-NET (gastric, colorectal or pancreatic NET) who had undergone surgical resection at the Affiliated Hospital of Nantong University (Nantong, China) between January 2009 and January 2014 and had been evaluated and classified according to the WHO 2010 classification (18). The tumor grading of these cases was based on proliferation and mitotic count.…”

“…During the last three decades, however, the reported incidence of GEP-NETs has increased worldwide due to improvements in diagnostic tools and clinical awareness of them (15). According to the latest 2010 World Health Organization (WHO) classification (18), GEP-NETs are divided into three types, namely well-differentiated NET, poorly differentiated neuroendocrine carcinoma and mixed adenoneuroendocrine carcinoma, and their pathology can be further graded as G1 [<2 mitoses/10 high power fields (HPFs) and/or Ki-67 index ≤2%], G2 (2-20 mitoses/10 HPFs and/or Ki-67 index between 3 and 20%) and G3 (≥21 mitoses/10 HPFs and Ki-67 index >20%) (18)(19)(20)(21)(22).…”

Expand+In Vivoiv.iiarjournals.orgIn Vivo September-October 2017 vol. 31 no. 5 1011-1017 Lymph Node Size on Computed Tomography Images Is a Predictive Indicator for Lymph Node Metastasis in Patients with Colorectal Neuroendocrine Tumors

“…According to WHO classification released in 2010, they are categorized into three groups according to their pathological features (2). The incidence of NETs in each organ is unclear.…”

“…The survival of a patient with NET differs among each pathological grade. Patients with colorectal NET G1 have the most beneficial 5-year survival from 92.1% to 100% (2,4), followed by those with NET G2. Even patients with neuroendocrine carcinoma (NET G3), the most aggressive subtype of NET, have a postoperative 5-year survival of 26.3-57.4% when distant metastasis is absent (5).…”