{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,15]],"date-time":"2026-01-15T20:33:03Z","timestamp":1768509183774,"version":"3.49.0"},"reference-count":25,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T00:00:00Z","timestamp":1767916800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Grant-in-Aid for Young Scientific Research from the Ministry of Education, Science, Technology, and Sports","award":["19K17393"],"award-info":[{"award-number":["19K17393"]}]},{"DOI":"10.13039\/100007449","name":"Takeda Science Foundation","doi-asserted-by":"publisher","award":["J24G0164"],"award-info":[{"award-number":["J24G0164"]}],"id":[{"id":"10.13039\/100007449","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Background: Site-specific long-term outcomes, including neurofibromatosis type 1 (NF1), Ki-67 prognostic value, and very late recurrences of small bowel gastrointestinal stromal tumors (GISTs), remain inadequately defined. Methods: This retrospective cohort study investigated the clinical characteristics, diagnostic challenges, and long-term outcomes of patients with small bowel GISTs. This retrospective, single-center study (2008\u20132024) analyzed 27 consecutive patients (average age: 62.2 years) with jejunal\/ileal GISTs. Clinicopathologic features, diagnostic yield of balloon-assisted enteroscopy (BAE), treatments, and outcomes were evaluated during a 10.2-year median follow-up period. Recurrence-free survival (RFS) and overall survival (OS) were estimated by Kaplan\u2013Meier with log-rank testing. Ki-67 was assessed using MIB-1; a prespecified 5% cut-off was chosen based on prior evidence. Results: Tumor (mean size, 62.4 mm) sites included the jejunum (74.1%) and ileum (25.9%). NF1 was present in 3\/27 (11.1%) patients, all with multiple jejunal tumors. Among the 14 patients who underwent BAE, biopsy was attempted in six and yielded a histological diagnosis in one (16.7%). Six patients had recurrence; two died from disease &gt;10 years postoperatively. Five-year OS and RFS were 91.3% and 68.7%, respectively. Adverse RFS was associated with ileal location (p = 0.03), size \u2265 10 cm (p &lt; 0.001), mitoses &gt; 5\/50 high-power fields (p = 0.002), and Ki-67 \u2265 5% (p &lt; 0.001). One patient labeled low risk by conventional models had recurrence with Ki-67 = 10%. Another classified as low risk by conventional models experienced recurrence &gt;10 years after surgery, with a Ki-67 index of 10%. Conclusions: Extended, risk-adapted surveillance may be reasonable for small-bowel GISTs, and it may be beneficial to incorporate Ki-67 (\u22655%) into site-based risk stratification. These observations remain hypothesis-generating and require validation in larger, multicenter cohorts and prospective studies.<\/jats:p>","DOI":"10.3390\/cancers18020218","type":"journal-article","created":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T14:15:50Z","timestamp":1767968150000},"page":"218","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Small Bowel Gastrointestinal Stromal Tumors: A 15-Year Cohort Study Focusing on Jejuno-Ileal Site-Specific Outcomes and Prognostic Factors"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5033-308X","authenticated-orcid":false,"given":"Yuichi","family":"Kojima","sequence":"first","affiliation":[{"name":"Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 9518510, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6792-1005","authenticated-orcid":false,"given":"Kentaro","family":"Tominaga","sequence":"additional","affiliation":[{"name":"Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 9518510, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuzo","family":"Kawata","sequence":"additional","affiliation":[{"name":"Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 9518510, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chizuru","family":"Kaneko","sequence":"additional","affiliation":[{"name":"Division of Molecular and Diagnostic Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata University, Niigata 9518510, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shuhei","family":"Kondo","sequence":"additional","affiliation":[{"name":"Division of Molecular and Diagnostic Pathology, Niigata University Graduate School of Medical and Dental Sciences, Niigata University, Niigata 9518510, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yoshifumi","family":"Shimada","sequence":"additional","affiliation":[{"name":"Division of Digestive and General Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 9518510, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1810-7709","authenticated-orcid":false,"given":"Junji","family":"Yokoyama","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology, Saiseikai Niigata Hospital, Niigata 9501104, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2443-3428","authenticated-orcid":false,"given":"Toshifumi","family":"Wakai","sequence":"additional","affiliation":[{"name":"Division of Digestive and General Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 9518510, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5439-635X","authenticated-orcid":false,"given":"Shuji","family":"Terai","sequence":"additional","affiliation":[{"name":"Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 9518510, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.annonc.2021.09.005","article-title":"Gastrointestinal stromal tumours: ESMO-EURACAN-GENTURIS Clinical Practice Guidelines for diagnosis, treatment and follow-up","volume":"33","author":"Casali","year":"2022","journal-title":"Ann. 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