January 25, 2017
By David Douglas
NEW YORK (Reuters Health) - Young adults with gastrointestinal stromal tumors (GISTs) appear to fare best after undergoing operative treatment, according to a retrospective study.
As Dr. Jason K. Sicklick told Reuters Health by email, "Our findings are important because they suggest that young patients with metastatic GIST should be considered for an operation when appropriate since this appears to be associated with improved survival."
"For the first time," he added, "we also show that small bowel GIST is associated with a better prognosis than stomach GIST in these patients. This is contrary to many reports showing that gastric tumors are generally associated with better outcomes in all patients with GIST."
For their study, online January 18 in JAMA Surgery, Dr. Sicklick of the University of California, San Diego, and colleagues studied data on 392 patients aged 13 to 39 years and more than 5,000 older patients.
The five-year GIST-specific survival was significantly higher in younger than older patients (83.3% vs. 75.4%). This was also the case for overall survival (82.4% vs. 67.1%). However, say the researchers, "this finding may be biased because of other comorbidities in the older adult group."
Overall, significantly more of the younger group was managed operatively than the older group (84.7% vs. 78.4%). They were also significantly more likely to have small-intestine GISTs (35.5% vs. 27.3%).
Multivariable analysis of outcome in the younger group showed that nonoperative management was associated with a more than twofold increased risk of death from GISTs (p=0.01).
On subset analysis of data from 349 of the younger group with tumors of the stomach and small intestine, the latter location was associated with improved overall survival (91.1% vs. 77.2%, p=0.01). Operative management was also associated with improved overall survival in 91 younger patients with metastatic disease (69.5% vs. 53.7%, p=0.04).
In an accompanying editorial, Drs. Donal B. O'Connor and Kevin C. Conlon of The University of Dublin, Ireland, point out, "A significant limitation of the current study is the absence of information on adjuvant tyrosine kinase inhibition (TKI) use."
"The use of TKIs during the last decade in the management of GISTs," they add, "has had a definitive effect on disease-free survival and overall survival and would be expected to have an effect on adolescent and young adult patients."
Nevertheless, they conclude that the authors "should be congratulated for adding to our understanding of GISTs in young adults - a group for whom limited information currently exists."
Dr. Carmen Mueller of McGill University in Montreal, Canada, told Reuters Health by email, "This study confirms for younger patients what we already knew about GISTs for older patients, which is that patients who are able to undergo surgery regardless of disease stage do better in the long run."
Dr. Mueller, an assistant professor of surgery who was not involved in the study, added, "It is surprising that young patients with GISTs of the small intestine did better than those with GISTs of the stomach; this is contrary to what has been found for older adults in which gastric GISTs tend to have more favorable outcomes and the reasons for this difference bear further study."
She also commented on the absence of data on TKIs, pointing out that, "What is not captured in this study is the role of targeted adjuvant therapy (usually imatinib) in improving overall survival and GIST-specific survival in younger patients as has been shown for all GIST patients generally. Currently imatinib is used to prevent recurrence in patients with high-risk GISTs for three years after resection. However, in younger adults with a long life expectancy, this time frame may need to be reexamined. There is emerging data to suggest imatinib should be used for longer than three years, although this is balanced against the risk of side effects and of the tumor developing drug resistance with prolonged use."
SOURCE: bit.ly/2jp6WYj and bit.ly/2joPrHQ
JAMA Surg 2017.
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