Clinical and pathological features of "small" GIST (≤2 cm). What is their prognostic value?

INTRODUCTION: Small GIST (<2 cm) are tumors whose biological behavior is benign and frequently involutes. Despite their increasing incidence, few studies have addressed the characteristics of these GIST. The aim of this work is to clarify the management of this entity. PATIENTS AND METHOD: The characteristics of ≤2 cm GIST were initially described, and then compared with those >2 cm. This series comprises 104 patients and they were divided according to tumor size in 4 groups: tumors which are ≤2 cm (group 1, G1), >2 and ≤ 5 cm (G2), >5 and ≤ 10 cm (G3) and >10 cm (G4). RESULTS AND DISCUSSION: Most of small GIST were asymptomatic and incidental, and were located in the stomach. There is an association between patients with associated tumors and asymptomatic GIST. A high overall mortality rate of up to 40% is observed being disease-specific mortality 4.5%. The disease-specific mortality increases proportionally with size. The overall survival (OS) at 5 years are lower for both <2 cm (61%) and >10 cm (53%) than the rest (85-91%). When analyzing the impact of tumor association on <2 cm GIST, we observed that the OS of patients with non-associated tumors was much higher than in the associated ones (90% vs 32% at 5 years, respectively), while no differences were observed in the disease specific survival. CONCLUSIONS: Small GIST are tumors that are very often incidentally discovered in the course of complementary examinations. Its prognosis is very good, but it depends on the associated tumor.