ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2019) 63 P44 | DOI: 10.1530/endoabs.63.P44

Comparative study between autoimmune metaplastic atrophic gastritis (AMAG) and type 1 gastric neuroendocrine tumors (G-NETs) in Hospital Clinico San Carlos (HCSC), Madrid

Elvira Ramos, Ignacio Vargas-Zuñiga, Elvira Barrio, Pablo Suárez, Mario Pazos, Raquel Pallarés, Paula Aldama, Nuria García De La Torre, Concepción Sevilla & Jose Ángel Díaz

Hospital Clínico San Carlos, Madrid, Spain.

Introduction: Type 1 Gastric neuroendocrine tumors account for 70 to 80 percent of all gastric neuroendocrine tumors (G-NETs) and they are found more commonly in older adults, particularly women. They are associated with autoimmune metaplastic atrophic gastritis (AMAG) with or without pernicious anemia. Endoscopically, they are usually smaller than 1 cm and often multiple. These tumors usually present a non-aggressive evolution. Our goal is to approach the presence of risk factors to develop G-NET in patients with AMAG.

Material and methods: Descriptive and observational study of 16 patients diagnosed with AMAG (controls) and 31 patients diagnosed additionally with type 1 G-NET (cases). The 47 patients were retrieved from the Endocrinology department of HCSC in the last 15 years. Variables between both groups were compared using the statistical program SPSS 23.0.

Results: Mean age was 64.75 (SD 12.03) in controls and 63.47 (SD 11.35) in cases. 75% of controls and 62% of cases were female. The diagnosis of AMAG in controls was due to vitamin B12 deficiency in 68.8%. In cases the diagnosis of G-NET was due to follow-up AMAG in 40.6%. We did not find differences between the personal and family history in both groups. 86.7% of controls and 71.8% of cases were non-smokers without reaching statistical significance. The presence of H. pylori was found in 18.8% of controls and in 3.1% of cases (P=0.101). The median of vitamin B12 in controls was 186 pg/ml (IQR 141.5–398.5) and 288 pg/ml (IQR 204–386) in cases (P<0.05). There were no statistically significant differences in the levels of hemoglobin, ferritin or serum iron although the median values were lower in controls. Regarding autoimmunity, anti-parietal cell antibodies could protect the development of G-NET OR: 0.192 (0.038–0.956). We found a higher prevalence of intrinsic factor antibodies in controls (41.2% vs 21.7) that was not statistically significant (P=0.185).

Conclusions: In our sample, the presence of anti-parietal cell antibodies might be a protective factor against G-NET development. However other studies are needed to support these results in other populations. Vitamin B12 levels were significantly higher in cases than in controls. Further research confirming these data might help to establish the usefulness of Vitamin B12 levels in early diagnosis of G-NET in patients with AMAG. Larger studies are necessary to assess whether the presence of intrinsic factor antibodies and H.Pylori infection are indeed associated with a lower risk of developing G-NETs in patients with AMAG.