Clinical characteristics and long‐term prognosis of type 1 gastric neuroendocrine tumors in a large Japanese national cohort

Abstract

ObjectivesOptimal management of type 1 gastric neuroendocrine tumors (T1‐GNETs) remains unknown, with few reports on their long‐term prognosis. This study investigated the clinical characteristics and long‐term prognosis of T1‐GNETs.MethodsWe reviewed the medical records of patients diagnosed with T1‐GNET during 1991–2019 at 40 institutions in Japan.ResultsAmong 172 patients, endoscopic resection (ER), endoscopic surveillance, and surgery were performed in 84, 61, and 27, respectively, including 27, 77, and 2 patients with pT1a‐M, pT1b‐SM, and pT2 tumors, respectively. The median tumor diameter was 5 (range 0.8–55) mm. Four (2.9%) patients had lymph node metastasis (LNM); none had liver metastasis. LNM rates were significantly higher in tumors with lymphovascular invasion (LVI) (15.8%; 3/19) than in those without (1.1%; 1/92) (P = 0.016). For tumors <10 mm, LVI and LNM rates were 18.4% (14/76) and 2.2% (2/90), respectively, which were not significantly different from those of tumors 10–20 mm (LVI 13.3%; 2/15, P = 0.211; and LNM 0%; 0/17, P = 1.0). However, these rates were significantly lower than those of tumors >20 mm (LVI 60%; 3/5, P = 0.021; and LNM 40%; 2/5, P = 0.039). No tumor recurrence or cause‐specific death occurred during the median follow‐up of 10.1 (1–25) years. The 10‐year overall survival rate was 97%.ConclusionsType 1 gastric neuroendocrine tumors showed indolent nature and favorable long‐term prognoses. LVI could be useful in indicating the need for additional treatments. ER for risk prediction of LNM should be considered for tumors <10 mm and may be feasible for tumors 10–20 mm.Trial registrationThe study protocol was registered in the University Hospital Medical Information Network (UMIN) under the identifier UMIN000029927.

A Rare but Aggressive Malignancy: A Case Report of a Gastrointestinal Neuroectodermal Tumor (GNET)

“…The prognosis of malignant GNETs is generally poor, with a high risk of recurrence and metastasis [ 2 ]. The rarity of these tumors limits our understanding of their natural history and optimal management strategies.…”

“…Clinical manifestations vary widely and are often nonspecific, encompassing symptoms such as abdominal pain, weight loss, fatigue, and gastrointestinal bleeding. The lack of specific clinical features further complicates the early diagnosis and recognition of GNETs, frequently resulting in delayed or missed diagnoses [ 2 ].…”

Differential Diagnoses and Management Approaches for Gastric Polyposis

“…An analysis of 172 Japanese patients with autoimmune gastritis and histologically confirmed neuroendocrine tumors revealed that half of the patients (n = 84, 50.0%) had multiple tumors, while the other half had solitary lesions [58]. The location was most predominantly in the gastric body (n = 139, 88.5%), and the color was yellow (n = 82, 64.6%), followed by red (n = 38, 29.9%), pale (n = 5, 3.9%), and similar color to that of the background mucosa (n = 2, 1.6%).…”