title: Population-Based Epidemiology and Mortality of Small Malignant Gastrointestinal Stromal Tumors in the USA.
abstract: Gastrointestinal stromal tumors (GISTs) have significant variability in size and malignant behavior. Our current understanding is limited to pathological analyses, autopsy studies, and small case series. The aim of the current study is to define the risk factors, incidence, and mortality rates of GIST <2 cm in the National Cancer Institute's Surveillance, Epidemiology, and End Results database.
  
  
  
  Patients with histologically confirmed malignant GIST <2 cm were studied from 2001 to 2011. GIST was defined by GI tumor site codes and GIST-specific histology codes.
  
  
  
  We identified 378 patients with GIST <2 cm. The average age at diagnosis was 64.0 years with equal sex distribution. The most common tumor location was the stomach (62.2 %), followed by the small intestine (23.3 %), colon (5.6 %), and rectum (3.4 %). Most patients had localized disease (79.4 %), but 11.4 % had regional/distant metastatic disease. The annual incidence rate was 4.2 per 10,000,000 (10M). This was the highest among Blacks (7.6 per 10M). Among patients with GIST and no additional cancers, the 5-year GIST-specific mortality was 12.9 %. Moreover, there was a significantly increased 5-year GIST-specific mortality in those patients who had regionally advanced (34.0 %) or metastatic GIST (34.3 %), as compared to those patients with localized GIST (5.6 %).
  
  
  
  This study represents the first population-based analysis of malignant GIST <2 cm. While quite rare, these tumors have an underappreciated disease-specific mortality. Further studies are needed to define the underlying reasons for the identified racial differences, to develop novel risk assessment schema for patients with these small tumors, and to determine appropriate indications for resection and/or medical therapy.
authors.affiliation: School of Medicine, University of California, La Jolla, CA, USA.
authors.forename: Taylor M
authors.initials: TM
authors.lastname: Coe
authors.affiliation: School of Medicine, University of California, La Jolla, CA, USA.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Fero
authors.affiliation: School of Medicine, University of California, La Jolla, CA, USA.|Division of Hematology and Oncology, Moores Cancer Center, University of California, San Diego, La Jolla, CA, USA.
authors.forename: Paul T
authors.initials: PT
authors.lastname: Fanta
authors.affiliation: Division of Surgical Oncology and Department of Surgery, Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0987, La Jolla, CA, 92093-0987, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Mallory
authors.affiliation: Division of Surgical Oncology and Department of Surgery, Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0987, La Jolla, CA, 92093-0987, USA.
authors.forename: Chih-Min
authors.initials: CM
authors.lastname: Tang
authors.affiliation: School of Medicine, University of California, La Jolla, CA, USA.|Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, University of California, San Diego, La Jolla, CA, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Murphy
authors.affiliation: School of Medicine, University of California, La Jolla, CA, USA. jsicklick@ucsd.edu.|Division of Surgical Oncology and Department of Surgery, Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, Mail Code 0987, La Jolla, CA, 92093-0987, USA. jsicklick@ucsd.edu.
authors.forename: Jason K
authors.initials: JK
authors.lastname: Sicklick
mesh_terms: D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D000369:Aged, 80 and over; D001213:Asian / Q000706:statistics & numerical data; D003106:Colon; D016208:Databases, Factual; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology* / Q000401:mortality / Q000473:pathology*; D046152:Gastrointestinal Stromal Tumors / Q000453:epidemiology* / Q000401:mortality / Q000556:secondary*; D006801:Humans; D015994:Incidence; D007421:Intestine, Small; D008297:Male; D008875:Middle Aged; D044468:Native Hawaiian or Pacific Islander / Q000706:statistics & numerical data; D012007:Rectum; D012307:Risk Factors; D018426:SEER Program; D013270:Stomach; D047368:Tumor Burden; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult
keywords: GIST tumorlet; ICC hyperplasia; Minute GIST; Small GIST