Clinicopathological characterization of gastroenteropancreatic neu-roendocrine neoplasms: a retrospective study of 48 cases
Authors: Sun Jianguo , Zhang Xiaodong , Lei Songjing , Xu Jingzhong , Qin Zhaoyang 
Published: June 2023

Abstract

Objective
Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) constitute a rare and heterogeneous group of tumors with varied biology and still constitute a diagnostic and therapeutic challenge for physicians of all specialties. In the present study, we aimed to review and study the clinicopathological characteristics of GEP-NENs applying the World Health Organization (WHO) 2010 grading criterion.

Methods
A total of 48 patients were enrolled in the study. The study included patients diagnosed with GEP-NENs who were treated and followed up at our Hospital from January 2013 to December 2017. Data regarding clinicopathological features of the patients were retrospectively evaluated. The expression of neuroendocrine markers was measured using the immunohistochemical Ultra Sensitive
TM
S-P method of staining in 48 cases of primary GEP-NENs; and serum levels of neuron-specific enolase, carbohydrate an-tigen 19-9, and carcinoembryonic antigen in 36 GEP-NEN patients were measured using the electrochemiluminescence method.

Results
The median age at presentation was 59.3 (range 48-82) years, and 39 cases (81.3%) were seen between the 5th and 6th decades. There was a male predilection (male: female=3:1). In 79.2% cases (38/48), tumors were hormonally nonfunctional. The most common presentation was abdominal pain, and the most frequent primary site of the tumor was the rectum, followed by the stomach (n = 15, 31.3%), colon (n = 5, 10.4%), and so on. Of the 48 tumors, 16 (33.3%) were G1, 6 (12.5%) cases were G2, 16 (33.3%) were neuroendocrine carcinoma (NEC), and 10 (20.8%) were mixed adenoneuroendocrine carcinoma (MANEC). According to the AJCC/UICC classification, 45.8% (n = 22) were diagnosed at low stage (stage I or II) while 54.2% (n = 26) were diagnosed at high stage (stage III or IV) (the majority of NEC, G3, and MANEC). A male preponderance was noted for all tumors except for G2 neoplasms, which showed no gender predilection. Thirty-nine patients underwent endoscopic biopsy. The lesions in 18.8% (n = 9) of the patients were indentified only radiologically. After the surgical procedures, 36 had at least one follow-up visit with a median follow-up duration of 5 months; the mean follow-up period was 28 ± 16 months. The one-year and three-year survival rates were 72.2% (26/36) and 61.1% (22/36), respectively. This study did not find an effect of grade 3 (G3) of tumor on the short-term clinical outcome of these patients. In the survival analysis, NEN G3, higher stage (stage III or IV) according to the AJCC/UICC classification (P < 0.05), and metastases at diagnosis (P < 0.05) were associated with poorer prognosis.

Conclusion
Most GEP-NENs are nonfunctional and nonspecific in presentation. The most frequent primary site of the tumor was the rectum and the commonest ages at diagnosis were the 5th and 6th decades. Endoscopic biopsy is the main diagnostic and histological grading method for GEP-NEN. In the survival analysis, NEN G3, a higher stage according to the AJCC/UICC classification, and metastases at diagnosis are associated with poorer prognosis.