Study Identifies Groups at Risk for Gastrointestinal Stromal Tumors


Key Points

  • The overall incidence rate of GIST, which rose from 2001 to 2011, was 6.8 cases per million people.
  • GIST was more common among men vs women and in blacks and Asian/Pacific Islanders vs whites.
  • Patients of Asian descent had not previously been identified as an at-risk population.

Researchers at the University of California, San Diego, School of Medicine have, for the first time, clearly defined the epidemiology of gastrointestinal stromal tumors (GIST), which occur primarily in the lining of the stomach and small intestine. Of note was the discovery that patients of Asian descent, who had not previously been identified as an at-risk population, are 1.5 times more likely than other patient groups to be diagnosed with this type of tumor. Results of the study were reported by Sicklick et al in Cancer Epidemiology, Biomarkers & Prevention.

“Previous journal articles never clearly differentiated GIST from several other tumors, even though they have different biologies,” said Jason Sicklick, MD, Assistant Professor of Surgery and a surgical oncologist at UC San Diego Health System. “This study more clearly identifies at-risk populations in the United States as well as incidence rates, survival trends, and risk factors for the disease.”

Prior to 2001, GIST-specific histology codes were not used in medical coding, which meant that a variety of tumor types, such as leiomyoma and leiomyosarcoma, spindle cell, myofibroblastic, desmoid, and KIT-positive metastatic melanomas were all lumped into one category. In the current study, Dr. Sicklick and his team used a new generation of precise pathologic diagnostic codes to better define the incidence and distribution of GIST among different patient groups.

Study Details

The investigators found that the overall incidence rate of GIST was 6.8 cases per million people and that the rate rose from 2001 to 2011. During the study period, the median age at GIST diagnosis was 64 years old. GISTs were more common in men. 

“Contradicting prior reports, we see a definite survival disparity, particularly among patients of African American descent,” said Dr. Sicklick. He noted that contrary to prior reports, the current study demonstrated a “definite survival disparity,” particularly among black patients. Persons of African or Asian/Pacific Islander descent were 2.1 and 1.5 times more likely to develop GIST than whites, respectively.

“Further studies are needed to understand why these groups are at risk, as it could carry important diagnostic, prognostic, and therapeutic implications throughout the United States,” said James Murphy, MD, Assistant Professor of Radiation Oncology at UC San Diego School of Medicine and a radiation oncologist at UC San Diego Health System.

Dr. Sicklick is the corresponding author for the Cancer Epidemiology, Biomarkers & Prevention article.

This study was funded by the National Institute of Health (KL2 RR031978) and the GIST Research Fund.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.