Invasive GIST Originating in the Stomach/Small Intestine Is More Common in Men, Study Shows

In patients with stage IV gastrointestinal stromal tumors, the rarity of the disease and likeliness of it leading to hepatic metastases was demonstrated, but, notably, the overall survival rate in the rare patient population was up to 51% at 5 years.

Stage 4 GIST, although a rare cancer, commonly starts in the small intestine and stomach in men, according to a poster presented at the virtual ASCO Gastrointestinal Cancers Symposium.

In addition, patients frequently had hepatic metastases and great overall survival at 5 years, according to the poster.

“Combined surgery [and] systemic therapy demonstrates best outcomes, although surgical resection alone might yield comparable results in selected patients,” the Johannes Uhlig, MD, MPH, resident in the department of diagnostic and interventional radiology at University Medical Center Goettingen in Denmark and visiting researcher in the department of radiology and biomedical imaging at Yale School of Medicine and colleagues wrote in the abstract.

To assess the epidemiology, treatment and outcomes of patients with stage 4 gastrointestinal stromal tumors, researchers queried data from the United States National Cancer Database from 2010 to 2016. This analysis focused on 1,578 patients with invasive stage 4 gastrointestinal stromal tumors without prior malignant disease.

The number of patients in this study represented 13.3% of all patients with gastrointestinal stromal tumors. The men-to-women ratio of these patients was 1.38:1. Patients were diagnosed with gastrointestinal stromal tumors at a median age of 62 years with a median tumor diameter of 10 cm. Most patients had cancer in the stomach (55.4%) and small intestine (40%). More than half of the patients had distant organ metastases (58.7%), with the most common being hepatic, occurring in 50.8% of patients.

Most patients were treated with systemic therapy (78.6%) either combined with surgery (43.3%) or alone (35.4%). For patients who underwent surgical resection, 6.9% received neoadjuvant systemic therapy, 32% received adjuvant therapy and 5.1% received a combination of both. In addition, 12.9% of patients underwent surgical resection alone.

Overall survival rates for patients with gastrointestinal stromal tumors were 88% at 1 year, 77% at 2 years, 67% at 3 years and 51% at 5 years.

Based on multivariable Cox proportional hazard models, researchers found that primary treatment for gastrointestinal stromal tumors independently affected overall survival. Patients had shorter overall survival when treated with systemic therapy alone (HR = 2.77; 95% CI, 2.12-3.61; P < .001) or no treatment (HR = 4.2; 95% CI, 2.75-6.43; P < .001) compared to treatment with surgery and systemic therapy. The difference in overall survival was not significant when patients treated with surgery and systemic therapy were compared with surgery alone (HR = 1.23; 95% CI, 0.88-1.72; P = .227). Overall survival was not statistically different when neoadjuvant, adjuvant and combined neoadjuvant and adjuvant systemic therapy was compared in subgroup analyses of patients who underwent surgical resection.

Patients treated at nonacademic centers had shorter overall survival compared with those treated at academic centers (multivariable HR = 1.36; 95% CI, 1.1-1.69; P = .005). Other independent predictors of overall survival included older age, men (vs. women; HR = 1.28; 95% CI, 1.03-1.59; P = .023), higher cancer grade, higher comorbidities and large cancer diameter.

_Reference:

_{Uhlig J, Stein S, Lacy J, et al. Stage IV gastrointestinal stromal tumors: Epidemiology, treatment and outcomes in adult US patients. Presented at: 2021 ASCO Gastrointestinal Cancers Symposium; January 15-17, 2021; virtual. Abstract 462.}