Gastrointestinal stromal tumours (GIST) are tumours that arise is the wall of the digestive tract, and most often occur in the stomach or small intestine.

Though more common in later in life, GISTs can occur in adolescents and young adults (AYA) under 40 years old as well.

Writing in JAMA Surgery, researchers at the University of California San Diego School of Medicine report findings from the first population-based analysis of AYA patients with GIST.

The retrospective cohort study, using the National Surveillance, Epidemiology and End Results database, looked at patients with recorded diagnoses of GIST between 2001 and 2013, with follow-up through 2015.

Of the 5,765 patients with recorded cases of GIST, 392 were AYA between the ages of 13 and 39.

The researchers, headed by senior author Jason Sicklick, MD, associate professor of surgery and surgical oncologist at Moores Cancer Center at UC San Diego Health, found that small intestine tumours in AYA patients were associated with improved survival compared to stomach tumours.

The opposite is true in older adult patients, according to Katherine Fero, lead author of the study.

"Many earlier studies, including one from our group, have shown that stomach GISTs have a better prognosis when we look at all patients with GIST. Thus, there is likely something biologically unique about GISTs in younger people."

Perhaps not surprisingly, AYA patients are more likely to be treated surgically than older adults (84.7 percent vs. 78.4 percent), who may have additional confounding health factors.

AYA patients whose tumours were managed non-operatively had a 2-fold increased risk of death from GIST.

In a subset analysis of AYA patients with metastatic GIST, surgical management was also associated with improved survival: 69.5 percent compared to 53.7 percent five years after diagnosis.

"The study suggests that in AYA patients, surgical management of their GIST is associated with improved overall and GIST-specific survival, including among patients whose cancer has spread," said Sicklick.

Source: University Of California - San Diego