Min-Hu Chen, MD, PhD
Jie Chen, MD, PhD
Neuroendocrine neoplasms (NEN) are a group of heterogeneous tumors arising from amine precursor uptake decarboxylation neuroendocrine cells. Epidemiological data according to the National Cancer Institute of United States (NCI), the National Cancer Registry of Spain (RGETNE), the Norwegian Registry of Cancer, and the nationwide Swedish Family-Cancer Database have shown that the incidence of NEN in western countries was 2.5-5/100,000 1-4. Over the past three decades, the incidence of NEN has significantly increased five-fold from 1.09/100,000 to 5.25/100,000. Contrasted with other tumors, the incidence of NEN increased more rapidly, which may due to the improvement of diagnostic precision, the increased awareness of NEN by clinicians, more frequent screening for tumors, and other environmental factors 1, 3. There are still no epidemiological data of NEN based on population in mainland China. However, an investigation from Taiwan showed that the incidence of NEN also increased five-fold from 0.3/100,000 in 1996 to 1.5/100,000 in 2008 5.
Gastroenteropancreatic Neuroendocrine Neoplasm (GEP-NEN) is the most common type of NEN, accounting for 65%-75% of NEN from all sites 6, 7. However, among different ethnicities and regions, the primary sites are different. In the Asian-Pacific region, the top three sites of GEP-NEN are rectum, pancreas, and stomach, while small intestinal NEN is much rarer 5. A multi-center retrospective pathological study in mainland China also indicates pancreas and rectum as the most common sites (data not yet published).
Since NEN can originate from any site throughout the body, and its clinical manifestations are so complex and diverse, accurate diagnosis of NEN is more complicated and more specialized than that of other tumors. The diagnostic method of NEN should be comprehensive, analyzing the results of serology, imaging, endoscopy, nuclear medicine, and pathology. Otherwise, treatment of NEN patients should be individualized with multidisciplinary comprehensive management, including procedures (endoscopy and surgery), interventional therapy and nuclide therapy, chemotherapy, biotherapy and molecular target therapy, etc. Compared to other tumors, more specialized departments should be involved in the diagnosis and treatment of NEN.
In mainland China, most of the physicians lack a thorough understanding of NEN and they often refer these patients to different departments. NEN patients were handled respectively by each specialized department before 2010. Chinese doctors started to pay attention to these rare tumors in 2010 when the nomenclature and classification of neuroendocrine tumors of digestive system were updated by the World Health Organization (WHO) 8. Thereafter, pathologists in China successively reached two consensuses on pathological diagnosis of GEP-NEN which were published in 2011 and 2013 respectively 9, 10. In clinical practice, some large medical centers successively started to set up neuroendocrine neoplasm multi-disciplinary teams (NEN-MDT). Various professional societies/studies (including the disciplines of gastroenterology, oncology, and pancreatic surgery) have released several related guidelines/consensuses for NEN respectively 11-13. However, few of these guidelines/consensuses reference clinical studies based on the Chinese population. By searching on the PubMed, we found that Chinese researchers have published 89 total articles on GEP-NEN in international journals between 2010 and 2015. However, 51 of them are small-scale single institution clinical studies. Only one is prospective study. No multi-center, co-operative clinical studies have been published.
Considering the current situation of diagnosis, management, and research of NEN in China, an increasing number of experts from NEN- related disciplines and fields have gradually gathered together and formed several professional NEN study groups. For instance, the Chinese Study Group for Neuroendocrine Tumors (CSNET), founded in 2015, is the first nation-wide interdisciplinary alliance of NET experts in China, including experts in various fields, such as medical oncology, gastroenterology, surgery, endocrinology, pathology, radiology, and nuclear medicine. Based on this open and cooperating platform, experts with a common goal set about establishing NEN databases, carrying out multi-center clinical trials and basic studies, and formulating expert consensus for point-to-point implementation. We firmly believe that it will not be long before more and more voices from China will be heard, both in the clinical and basic fields of NEN.