NCCN Guidelines® Insights: Gastrointestinal Stromal Tumors, Version 2.2022

Abstract

Gastrointestinal stromal tumors (GIST) are the most common type of soft tissue sarcoma that occur throughout the gastrointestinal tract. Most of these tumors are caused by oncogenic activating mutations in the KIT or PDGFRA genes. The NCCN Guidelines for GIST provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with these tumors. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines, including revised systemic therapy options for unresectable, progressive, or metastatic GIST based on mutational status, and updated recommendations for the management of GIST that develop resistance to specific tyrosine kinase inhibitors.

GIST-4

^c See Principles of Imaging (GIST-E). ^e Mutational analysis may predict response to therapy with TKIs (See GIST-B). ^k See General Principles of Surgery for GIST (GIST-C). ⁿ Consider baseline PET/CT, if using PET/CT during follow-up. PET/CT is not a substitute for CT. ^p PET/CT may give indication of imatinib efficacy after 2–4 weeks of therapy when rapid readout of activity is necessary. Diagnostic abdominal/pelvic CT or MRI with contrast is indicated every 8–12 weeks; routine long-term PET/CT follow-up is rarely indicated. Frequency of response assessment imaging may be decreased if patient is responding to treatment. ^q Progression may be determined by abdominal/pelvic CT or MRI with contrast with clinical interpretation; increase in tumor size in the presence of decrease in tumor density is consistent with drug efficacy or benefit. PET/CT scan may be used to clarify if CT or MRI are ambiguous. ^r Collaboration between medical oncologist and surgeon is necessary to determine the appropriateness and timing of surgery, following major response or sustained stable disease. Maximal response may require treatment for 6 months or more to achieve. ^v Consider resection or ablation/liver-directed therapy for hepatic metastatic disease. ^w Resection of metastatic disease, especially if complete resection can be achieved, and may be beneficial in patients on imatinib or sunitinib who have evidence of radiographic response, or limited disease progression.

GIST-5

^k See General Principles of Surgery for GIST (GIST-C). ^x Clinical experience suggests that discontinuing TKI therapy, even in the setting of progressive disease, may accelerate the pace of disease progression and worsen symptoms. ^y Reintroduction of a previously tolerated and effective TKI can be considered for palliation of symptoms. Consider continuation of TKI therapy life-long for palliation of symptoms as part of best supportive care.