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Upper Gastrointestinal (lips to ileocecal valve, including esophagus and stomach)

E452: Classification of Gastric Neuroendocrine Tumors and Associations with Survival

    ePoster Abstract Author(s)

  • Yun Song, MD (she/her/hers)

    Complex General Surgical Oncology Fellow
    The University of Texas MD Anderson Cancer Center
    Houston, Texas, United States

    • Submitter(s)

  • Yun Song, MD (she/her/hers)

    Complex General Surgical Oncology Fellow
    The University of Texas MD Anderson Cancer Center
    Houston, Texas, United States

    • Author(s)

  • Yun Song, MD (she/her/hers)

    Complex General Surgical Oncology Fellow
    The University of Texas MD Anderson Cancer Center
    Houston, Texas, United States

  • EC

    Eunise Chen, B.S.

    Medical Student
    McGovern Medical School, United States

  • YC

    Yi-Ju Chiang, MSPH

    Statistician
    The University of Texas MD Anderson Cancer Center, United States

  • JY

    James Yao, MD

    Professor, Department of Gastrointestinal Medical Oncology
    The University of Texas MD Anderson Cancer Center, United States

  • Daniel M. Halperin, MD

    Associate Professor, Department of Gastrointestinal Medical Oncology
    The University of Texas MD Anderson Cancer Center, United States

  • DC

    Deyali Chatterjee, MD

    Assistant Professor, Department of Pathology
    The University of Texas MD Anderson Cancer Center, United States

  • Brian Badgwell, MD, MS

    Professor of Surgery
    MD Anderson Cancer Center
    Houston, Texas, United States

Introduction: The World Health Organization (WHO) classifies gastric neuroendocrine tumors (GNETs) into 3 subtypes: type 1 tumors are associated with hypergastrinemia and arise in a background of atrophic gastritis, type 2 tumors are associated with gastrinomas, and type 3 are considered spontaneous, occurring in a background of normal gastric mucosa. However, certain tumors remain unclassified, and their prognostic significance is unknown. The purpose of this study is to better characterize GNET types and to determine associations with distant metastasis and disease-specific survival (DSS).

Methods: Patients diagnosed with GNET (1986-2021) were identified and categorized as having type 1, 2, or 3 tumors. Pathologic specimens of unclassified tumors were reviewed, and tumors were classified as proton pump inhibitor (PPI)-associated if there were prominent parietal and neuroendocrine cell hyperplasia in the background mucosa, in the absence of a gastrinoma and with a positive history of chronic PPI use. Characteristics by tumor type, associations with distant metastasis at initial diagnosis, and DSS were determined using standard statistical methods.

Results: Of 246 patients, 164 (66.7%) had type 1, 5 (2.0%) had type 2, 52 (21.1%) had type 3, 18 (7.3%) were PPI-associated, and 7 (2.8%) remained unclassified. Multifocal disease was more common for types 1 (56.1%) and 2 (40.0%) than type 3 (13.5%) and PPI-associated tumors (27.8%, P< 0.001). Distant metastasis at diagnosis occurred more frequently with type 3 (38.5%) than type 1 (1.2%), type 2 (20.0%), and PPI-associated tumors (11.1%, P< 0.001). GNET type (type 1 vs 3, odds ratio [OR] 0.005 [95% confidence interval [CI] 0.001-0.050; PPI-associated vs type 3, OR 0.040 [95% CI 0.004-0.45]), race (non-white vs white, OR 0.17 [95% CI 0.040-0.73]), and WHO grade (2/3 vs 1, OR 10.5 [95% CI 1.93-57.2]) were associated with distant metastasis at diagnosis. Five-year DSS rates were 100.0% for type 1, 59.7% (95% CI 42.7-73.2%) for type 3, and 90.9% (95% CI 50.8-98.7%) for PPI-associated (P< 0.001). By multivariable analysis, multifocality of primary tumors (hazard ratio [HR] 0.070 [95% CI 0.010-0.46]) and distant metastasis at diagnosis (HR 44.9, 95% CI 6.21-324.8) were independently associated with DSS, while tumor type was not (type 1 vs 3, HR 0.18 [95% CI 0.010-2.44); PPI-associated vs type 3, HR 0.13 [95% CI 0.010-1.33]).    

Conclusions: PPI-associated tumors may represent a distinct GNET type with intermediate outcomes compared to type 1 and type 3 tumors. However, factors other than tumor subtype must be considered in overall prognosis.

Learning Objectives:

  • Describe the subtypes of gastric neuroendocrine tumors.
  • Define characteristics associated with different gastric neuroendocrine tumor subtypes.
  • Describe outcomes associated with different gastric neuroendocrine tumor subtypes.