Pre-Operative Gastric Gist Downsizing: The Importance of Neoadjuvant Therapy

Abstract

Introduction:Gastric gastrointestinal tumors (GIST) are a rare and usually asymptomatic neoplasm that can present as abdominal mass in more advanced scenarios. Since surgical resection is the main aspect of the treatment, locally advanced tumors require multivisceral resection and, therefore, higher postoperative morbidity and mortality. Objective:To perform a review the literature on the topic, with emphasis on the neoadjuvant therapy. Methods:Literature review on the Medline database using the following descriptors: gastrointestinal stromal tumors, neoadjuvant therapy, imatinib mesylate and molecular targeted therapy. Results:Surgical resection remains the cornerstone for the treatment of GISTs; however, tyrosine kinase inhibitors have improved survival as an adjuvant therapy. More recently, neoadjuvant therapy have been described in the treatment of locally advanced tumors in order to avoid multivisceral resection. Conclusion:Despite surgical resection remains as the most important aspect of the treatment of GISTs, adjuvant and neoadjuvant therapy with tyrosine kinase inhibitors have shown to both improve survival and resectability, respectively.

The Role of Conventional Echoendoscopy (Eus) in Therapeutic Decisions in Patients With Neuroendocrine Gastrointestinal Tumors

“…Endoscopic resection must remove the tumor completely (R0 resection) 22,29 . To date, no recurrence has been observed after polypectomy/mucosectomy that affects the prognosis 20 .…”

Review of Management of Gastrointestinal Stromal Tumor in Low-Resource Centers

“…TKI can be used in neoadjuvant and adjuvant therapy. Gene sequencing of a biopsy or FNAC sample is required before treatment with medical therapy (neoadjuvant or adjuvant therapy) to determine tumor response as mutation to PDGFA; 10% of other mutations show no response to TKI [7], [12]. However, there is no established criteria to measure tumor response [17].…”

“…Neoadjuvant therapy is recommended for 4 to 6 months, but such treatment should be decided on individual basis [36]. Imaging is used to detect the response to neoadjuvant therapy [12], [13], [33]. Reference [4] reports that reduced tumor size and vascularization as a response to neoadjuvant therapy result in reduced chances of tumor rupture and peritoneal implantation.…”

“…GIST is usually asymptomatic and/or incidentally diagnosed during surgery or on imaging [12], [13]. Clinical presentation and management of GIST depend on size and location of the tumor and its clinical features [14].…”

“…Since 95% of GIST are positive for CD117, diagnosis is based on a positive stain of KIT (CD117) on immunohistochemical (IHC) staining [15], [16]. Surgical resection with clear margins for resectable GIST and for GIST with resectable oligometastasis can be liver or peritoneal metastasis [12], [17].…”