External beam radiation therapy for locally advanced and metastatic gastrointestinal stromal tumors

Abstract

BackgroundThe role of radiation therapy (RT) in the management of gastrointestinal stromal tumors (GIST) is not well described. Here we report our institutional experience for patients with locally advanced or metastatic GIST treated with RT.MethodsBetween 1997 and 2012, 15 patients with 22 GISTs were treated with RT at our center. The median age was 68 (range, 41–86). Fourteen patients had stage IV disease and 1 patient had stage IIIB disease, per the American Joint Committee on Cancer (AJCC), 7th Edition staging. Tumors were in a variety of locations, and were most commonly referred for palliative treatment. Eighteen of 22 tumors were symptomatic. Prior to RT, 14 of 15 patients received systemic therapy in the form of tyrosine kinase inhibitors (TKIs) (n = 11), chemotherapy (n = 4), or both (n = 1). TKIs were used concurrently for nine tumors (40.9%). No tumors were treated with concurrent chemotherapy. Several fractionation schemes were used, most commonly 3 Gy × 10 (n = 8). Local progression-free survival and overall survival were estimated using the Kaplan-Meier method. Acute toxicity was graded per Common Terminology Criteria for Adverse Events (CTCAE) v4.0.ResultsThe median follow-up was 5.1 months (range, 1.3-28.3). At the time of analysis, 12 patients have died (80%). The estimated 6-month local progression-free survival and overall survival were 57.0% and 57.8%, respectively. Among the 18 symptomatic tumors, at least partial palliation was achieved in 17 (94.4%), and symptoms were completely palliated in eight (44.4%). Treatment was well tolerated, with no Grade 4 or 5 toxicities. There was no Grade ≥3 toxicity associated with concurrent TKI use.ConclusionsIn this largest series to date of GISTs treated with RT, a high rate of palliation was achieved for symptomatic tumors in a cohort of advanced stage, heavily pretreated patients. Treatment was well tolerated, and concurrent use of tyrosine kinase inhibitor therapy was not associated with additional toxicity. While follow-up was short, durable control is possible for some patients, providing evidence that GIST is not universally radioresistant and that RT can provide an important benefit in patients with progressive or metastatic disease.

Somatostatin Receptor Avidity in Gastrointestinal Stromal Tumors: Theranostic Implications of Gallium-68 Scan and Eligibility for Peptide Receptor Radionuclide Therapy

“…It is unclear if this biomarker feature is specific to SDH-deficient GIST, or if the presence of somatostatin receptors is a common finding in all types of GIST, which seems very plausible. Lastly, the inclusion of radiotherapy in the management of GIST is considered mostly for palliation, and there is emerging recent data suggestive that the concomitant use of TKIs may improve its efficacy, such as in the present case [ 9 - 10 ]; this was further demonstrated by the significant response to stereotactic body radiation therapy (SBRT) in the liver and the retropharyngeal mass sites reported by 18F-FDG PET/CT.…”

Metastatic Cerebellar Gastrointestinal Stromal Tumor with Obstructive Hydrocephalus Arising from the Small Intestine: A Case Report and Review of the Literature

“…Although radiotherapy is not a standard therapy for GIST, Cuaron et al described the importance of this option for the management of locally advanced and metastatic GISTs [ 29 ]. In a series of 18 patients treated with radiotherapy, the estimated 6-month local progression-free and overall survival rates were 57.0% and 57.8%, respectively.…”

Treatments for Gastrointestinal Stromal Tumors that are Resistant to Standard Therapies

“…Thus, radiotherapy has been historically administered in GIST patients only with a palliative/antalgic aim and mainly for bone metastases. However, a few experiences show that selected patients could benefit from radiotherapy in specific sites, thus obtaining not only high rates of palliation for symptomatic tumors in a cohort of advanced-stage, heavily pretreated patients, but also initial tumor shrinkage and subsequent durable disease stabilization [71][72][73][74][75]. In this sense, radiotherapy integrated with systemic therapy could provide an important benefit in selected patients with progressive or metastatic disease.…”