Gastric neuroendocrine tumor Medical Services in China

Gastric neuroendocrine tumors (gNETs) are rare, slow-growing neoplasms arising from enterochromaffin-like (ECL) cells or other neuroendocrine cells in the gastric mucosa. Classified under gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), gNETs are histologically and clinically heterogeneous, with three main types: Type 1 (associated with chronic atrophic gastritis and hypergastrinemia, most common and least aggressive), Type 2 (linked to Zollinger-Ellison syndrome and multiple endocrine neoplasia type 1, rare), and Type 3 (sporadic, gastrin-independent, more aggressive with higher metastatic potential). Pathogenesis involves dysregulated gastrin signaling—particularly in Types 1 and 2—leading to ECL cell hyperplasia, dysplasia, and eventual tumorigenesis; Type 3 arises de novo via somatic mutations (e.g., in DAXX, ATRX, MEN1, or mTOR pathway genes) without hormonal driver involvement. Epidemiologically, gNETs account for <1% of all gastric malignancies and ~2–6% of all gastrointestinal NETs. Incidence is rising globally, likely due to increased endoscopic detection and improved histopathological classification; age-adjusted incidence in high-income countries ranges from 0.2 to 0.6 per 100,000 person-years, with peak diagnosis in the sixth to seventh decades. Risk factors include chronic autoimmune atrophic gastritis (especially with pernicious anemia), long-standing proton pump inhibitor use (controversial but biologically plausible due to induced hypergastrinemia), familial syndromes (MEN1, VHL), and H. pylori eradication in predisposed individuals. Unlike many gastrointestinal cancers, gNETs often present asymptomatically—detected incidentally during endoscopy for dyspepsia or anemia—or with nonspecific symptoms such as epigastric discomfort, nausea, early satiety, or iron-deficiency anemia secondary to chronic mucosal bleeding. Hormonally functional tumors are exceedingly rare in the stomach and seldom cause carcinoid syndrome. Quality of life impact is multifaceted: while low-grade gNETs (especially Type 1) carry excellent 5-year survival (>95%), patients face lifelong surveillance (annual or biennial upper endoscopy with targeted biopsies), anxiety around progression risk, dietary adjustments, and potential complications from repeated endoscopic resections (e.g., stricture, bleeding). Higher-grade or metastatic disease necessitates systemic therapies (somatostatin analogs, peptide receptor radionuclide therapy, everolimus, or chemotherapy), which may cause fatigue, diarrhea, hyperglycemia, or myelosuppression—further affecting daily functioning, work capacity, and psychosocial well-being. Early diagnosis, accurate grading (Ki-67 index and mitotic count per WHO 2022 classification), and multidisciplinary management—including gastroenterology, pathology, nuclear medicine, and oncology—are critical to optimizing outcomes and preserving quality of life.

Gastric neuroendocrine tumors (gNETs) are rare, heterogeneous neoplasms arising from enterochromaffin-like (ECL) cells or other neuroendocrine cell lineages in the gastric mucosa. Classified primarily by the World Health Organization (WHO) into grades G1 (low-grade), G2 (intermediate-grade), and G3 (high-grade), and further stratified by etiology—most commonly type 1 (associated with chronic atrophic gastritis and hypergastrinemia), type 2 (Zollinger–Ellison syndrome with multiple endocrine neoplasia type 1), and type 3 (sporadic, gastrin-independent)—management must be individualized based on tumor size, grade, number, depth of invasion, lymph node involvement, and metastatic status. Treatment is coordinated within gastroenterology (digestive medicine) departments, often in multidisciplinary tumor boards involving endoscopists, surgical oncologists, nuclear medicine specialists, and medical oncologists.

Conservative management is appropriate for small, low-grade (G1/G2), non-invasive lesions (<1 cm), particularly in type 1 gNETs without evidence of deep submucosal invasion or lymphovascular infiltration. Endoscopic surveillance every 6–12 months with high-definition white-light and chromoendoscopy (e.g., indigo carmine) is standard. Serial serum chromogranin A (CgA), gastrin, and fasting gastric pH measurements help monitor disease activity and underlying hypergastrinemic drivers. In type 1 gNETs, long-term proton pump inhibitor (PPI) therapy—though necessary for symptom control in atrophic gastritis—is carefully evaluated, as prolonged hypergastrinemia may theoretically promote ECL-cell proliferation; however, current evidence does not support PPI discontinuation solely for tumor prevention in stable cases. Instead, optimization of gastric acid suppression while minimizing unnecessary dose escalation is advised. Lifestyle modifications—including smoking cessation, alcohol abstinence, and avoidance of chronic NSAID use—are recommended to reduce mucosal injury and inflammation.

Pharmacologic intervention centers on controlling hormonal syndromes and inhibiting tumor growth. Somatostatin analogues (SSAs), such as octreotide LAR (long-acting release) or lanreotide Autogel, are first-line for symptomatic hormone-secreting gNETs (e.g., carcinoid syndrome) and demonstrate antiproliferative effects in well-differentiated G1/G2 tumors, particularly those expressing somatostatin receptor subtype 2 (SSTR2), confirmed via 68Ga-DOTATATE PET/CT. Everolimus, an mTOR inhibitor, is indicated for progressive, advanced G1/G2 gNETs refractory to SSAs. Peptide receptor radionuclide therapy (PRRT) with 177Lu-DOTATATE is reserved for SSTR-positive, metastatic, progressive disease after SSA failure and is increasingly available in tertiary centers across China. Chemotherapy (e.g., capecitabine plus temozolomide) is considered for high-grade (G3) gNETs with poor differentiation or rapidly progressive disease, though response rates remain modest. Targeted agents like sunitinib have limited data in gastric-specific NETs and are not routinely recommended outside clinical trials.

Surgical treatment remains definitive for localized, higher-risk gNETs. Endoscopic resection (ER) — including endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) — is curative for lesions ≤2 cm confined to the mucosa or superficial submucosa (sm1), with en bloc resection and negative margins confirmed histologically. ESD offers superior R0 resection rates (>95%) compared to EMR for larger or fibrotic lesions and is widely performed in Chinese digestive medicine centers with high technical proficiency. For tumors ≥2 cm, deeply invasive (sm2/sm3), multifocal, or with lymphovascular invasion, laparoscopic or open gastrectomy—ranging from wedge resection to distal or total gastrectomy with D1+/D2 lymphadenectomy—is indicated. Radical surgery is mandatory for type 3 gNETs regardless of size due to their aggressive biology. In metastatic settings, cytoreductive surgery may be considered if >90% tumor burden can be safely resected and functional status permits.

China offers distinct advantages in gNET management. First, endoscopic expertise is exceptionally advanced: over 300 certified ESD training centers exist nationwide, with standardized protocols endorsed by the Chinese Society of Gastrointestinal Endoscopy (CSGE). Second, integrated diagnostics—including rapid turnaround 68Ga-DOTATATE PET/CT, next-generation sequencing for molecular profiling (e.g., MEN1, DAXX/ATRX), and centralized pathology review through national reference networks—enhance diagnostic accuracy. Third, cost-effective access to biosimilar SSAs and domestically manufactured PRRT isotopes (e.g., 177Lu-labeled peptides produced under NMPA approval) improves treatment affordability and timeliness. Fourth, large-scale prospective registries (e.g., the China Neuroendocrine Tumor Registry, CNTR) facilitate real-world evidence generation and protocol refinement. Finally, seamless coordination between tertiary hospitals and community health centers enables longitudinal follow-up with standardized electronic health records and AI-assisted lesion tracking during surveillance endoscopy.

Post-treatment recovery emphasizes structured, evidence-based monitoring and holistic support. Patients undergoing ER require 4–6 weeks of soft diet, avoidance of anticoagulants/NSAIDs, and repeat endoscopy at 3 months to confirm complete resection and assess for recurrence. After gastrectomy, nutritional rehabilitation with dietitian-led counseling—focusing on small, frequent meals rich in protein and vitamin B12 supplementation—is critical. All patients should undergo lifelong surveillance: CgA and gastrin every 3–6 months, abdominal MRI or CT every 6–12 months, and 68Ga-DOTATATE PET/CT annually for high-risk or metastatic cases. Psychosocial support—including access to oncology social workers and peer support groups—is integral, given the chronic, unpredictable nature of NETs. Patients are counseled to recognize red-flag symptoms (e.g., new-onset flushing/diarrhea, unexplained weight loss, gastrointestinal bleeding) and seek prompt evaluation. Finally, participation in clinical trials—particularly those evaluating novel radiopharmaceuticals, immunotherapies, or combination regimens—is actively encouraged, with over 40 active gNET-focused trials registered in China’s Clinical Trial Registry (ChiCTR).