Version May 2024
The approach to neoadjuvant therapy in patients with a confirmed diagnosis of localized GIST is presented here. Patients with disease that is resectable with minimal surgical morbidity do not need neoadjuvant therapy. However, some patients with disease that is resectable but with significant surgical morbidity require neoadjuvant therapy prior to resection of the primary tumor. Multidisciplinary input is necessary from medical oncology and surgical oncology. Clinical trials investigating neoadjuvant approaches are encouraged, where available.
The approach to adjuvant therapy for patients with localized GIST and systemic therapy for advanced and metastatic GIST is discussed separately.GIST: gastrointestinal stromal tumor; TKI: tyrosine kinase inhibitor; RT: radiation therapy; CT: computed tomography.
* Neoadjuvant therapy may allow patients to switch from an open to a minimally invasive surgical approach, avoid complex multivisceral resection, or preserve the affected organ in those with disease involving the esophagus, esophagogastric junction, duodenum, or rectum.
¶ Tumor mutational status can be used to guide selection and dosing of neoadjuvant therapy, but it may not be available for all patients due to institutional practice or limited tissue availability. Some UpToDate contributors do not obtain further molecular testing for patients receiving neoadjuvant imatinib whose tumor histology and immunohistochemistry are consistent with either a KIT or PDGFRA mutation. For those with insufficient tissue samples for molecular testing, repeat biopsy is not required if patients are responding to imatinib.
Δ We do not suggest the use of neoadjuvant avapritinib for PDGFRA D842V positive tumors. There are limited data for the efficacy of avapritinib in this setting, and there is a risk of long-term cognitive toxicity.
◊ For most patients on neoadjuvant therapy, we obtain a CT abdomen and pelvis with contrast to assess treatment response approximately two to three months after initiating TKI therapy. Since GIST may increase in size during early treatment due to intratumoral hemorrhage or myxoid degeneration, treatment response is defined as the absence of progression at the time of first imaging disease re-evaluation.
§ For most patients whose GIST is responding to neoadjuvant therapy, we obtain CT abdomen and pelvis with contrast to monitor treatment response every two to three months. In patients with stable disease at initial evaluation, maximal responses may be seen at six months or longer.
¥ Patients with high-risk tumors who are tolerating treatment well may elect to remain on imatinib for a total of five years or longer. In patients treated with adjuvant imatinib for up to three years who discontinue therapy, disease recurrence has been reported within 6 to 12 months of discontinuing therapy, suggesting that imatinib may maintain tumor dormancy rather than eradicate microdeposits.آیا می خواهید مدیلیب را به صفحه اصلی خود اضافه کنید؟
