Radiotherapy in the treatment of gastrointestinal stromal tumor

Abstract

Gastrointestinal stromal tumors (GISTs) are uncommon mesenchymal tumors of the gastrointestinal tract. Up to one-third of GISTs are malignant with a high rate of metastasis. Surgical resection is the mainstay of care for patients with resectable disease. Imatinib mesylate, a selective tyrosine kinase inhibitor, is the current standard of care for GISTs that cannot be completely resected or in cases of metastatic GIST. Although often overlooked, radiation therapy is a viable option for select patients with GIST. We report the case of a patient with unresectable GIST who was treated with local radiotherapy and achieved long-term response. We also present a review of the literature regarding the use of radiotherapy in the treatment of GIST. GIST has been shown to be a radiosensitive tumor. Radiotherapy can offer long-term local control and should be considered in the adjuvant or palliative setting. The role of radiotherapy delivered concurrently with imatinib in the treatment of GIST may warrant further investigation.

Treating ALK-positive lung cancer—early successes and future challenges

“…The logic behind this approach is that if resistance arises clonally, in conjunction with close CT or PET/CT observation, isolated areas of growth may be identified and deleted prior to more widespread dissemination of the resistant disease. 75-77 Within the Phase I study of crizotinib, thirty-seven patients continued to receive crizotinib for >2 weeks post-progression at the investigator’s discretion, 11 for more than 6 months from the time of their initial protocol-defined progression. 43 Although no formal details are available, in many cases this continuation likely occurred after areas of localized progression in both the body and/or CNS were treated with radiotherapy.…”

Considering the role of radiation therapy for gastrointestinal stromal tumor

“…Of note, patients treated with a dose per fraction >5 Gy (n=8) had a radiographic response rate of 63%, suggesting that GISTs are more sensitive to a higher radiation dose. Knowlton et al reported 20 years of durable local control in a 37-year-old man treated in the pre-imatinib era with debulking surgery and 36 Gy for an unresectable, non-metastatic GIST 47. Similarly, local control was reported in six of nine patients treated with 45–60 Gy of radiation for incompletely resected disease in the pre-imatinib era 48.…”

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.…”