Case Report: Stereotactic Body Radiation Therapy Produces a Durable Response in a Perirectal Gastrointestinal Stromal Tumor

Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms representing just 1% to 2% of primary gastrointestinal malignancies. The rectum is an uncommon primary site representing 5% of all GISTs.1 In view of the targetable c-kit mutation found in the majority of tumors, the mainstay of systemic therapy is tyrosine kinase inhibitors (TKIs). Although durable responses to TKI therapy are common, most patients subsequently develop resistance. Nonsurgical procedures rather than commencement of a subsequent line of systemic therapy can be considered in cases of focal progression.