Diagnostic and treatment strategy for small gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are considered to be potentially malignant mesenchymal tumors of the gastrointestinal tract. Clinically relevant GISTs are rare; however, subclinical GISTs (mini-GISTs) (1-2 cm) and pathologic GISTs (micro-GISTs) (<1 cm) are frequently reported. Most mini-GISTs and almost all micro-GISTs of the stomach may exhibit benign clinical behavior, and only mini-GISTs with high-risk features may progress. For this review, a provisional algorithm was used to propose diagnostic and treatment strategies for patients with small GISTs. Because surgery is the only potentially curative treatment, in its application for small GISTs, the principles of sarcoma surgery should be maintained, and cost effectiveness should be considered. Indications for surgery include GISTs measuring ≥2 cm, symptomatic GISTs, and mini-GISTs with high-risk features (irregular borders, cystic spaces, ulceration, echogenic foci, internal heterogeneity, and tumor progression during follow-up); however, a preoperative pathologic diagnosis is infrequently obtained. For small intestinal and colorectal GISTs, surgery is indicated irrespective of size because of their greater malignant potential. Otherwise, mini-GISTs without high-risk features, micro-GISTs, and small submucosal tumors measuring <5 cm without high-risk features may be followed by periodical endoscopic ultrasonography. Although surgical approaches and operative methods are selected according to tumor size, location, growth pattern, and surgical teams, laparoscopic surgery has produced similar oncologic outcomes and is less invasiveness compared with open surgery. After resection, pathologic examination for diagnosis and risk assessment is mandatory, and genotyping is also recommended for high-risk GISTs. Endoscopic resection techniques, although feasible, are not routinely indicated for most mini-GISTs or micro-GISTs. Cancer 2016;122:3110–8.