Clinicopathological characteristics and longterm survival of patients with synchronous multiple primary gastrointestinal stromal tumors: A propensity score matching analysis.

Background: Multiple gastrointestinal stromal tumors (MGISTs) are specific and rare. Little is known about the impact of MGISTs on the survival of patients with gastrointestinal stromal tumors (GIST). The diagnosis, treatment and follow-up strategies of MGISTs is not specifically described in guidelines.

Aim: To compare the clinicopathological characteristics and prognosis of MGISTs and solitary GISTs (SGISTs).

Methods: Patients diagnosed with primary GISTs from March 2010 to January 2020 were included. Due to the inhomogeneous distribution of several baseline characteristics and uneven MGIST and SGIST group sizes, propensity score matching was performed according to comorbidities, body mass index, tumor location, mitotic index, sex, age and American Society of Anesthesiologists score. Differences in clinicopathological characteristics and prognosis between patients with MGISTs and patients with SGISTs were compared.

Results: Among the entire cohort of 983 patients, the incidence of MGISTs was 4.17%. Before matching, patients with MGISTs and those with SGISTs had disparities in body mass index, surgical approach, tumor size and mitotic index. After 1:4 ratio matching, the clinical baseline data were comparable. The 5-year progression-free survival rate was 52.17% in the MGIST group and 75.00% in the SGIST group ( = 0.031). On multivariate analysis, tumor location, tumor size, mitotic index, imatinib treatment and MGISTs (hazard ratio = 2.431, 95% confidence interval = 1.097-5.386, = 0.029) were identified as independent prognostic factors of progression-free survival. However, overall survival was similar between the SGIST and MGIST groups.

Conclusion: Patients with MGISTs had poorer progression-free survival than patients with SGISTs. Risk criteria and diagnostic and treatment strategies should be developed to achieve personalized precision therapy and maximize the survival benefit.