The standard diagnosis, treatment, and follow-up of gastrointestinal stromal tumors based on guidelines

Molecular and Immunohistochemical Study of Platelet Derived Growth Factor Receptor Alpha in KIT Negative Gastrointestinal Stromal Tumors; the First Report from Iran

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are potentially malignant tumors; however their behavior and response to treatment is dependent on the type of mutation and immunohistochemical expression of antigens. It is recommended to perform routine molecular and immunohistochemical tests in KIT and platelet derived growth factor receptor alpha (PDGFRA) molecules for making decision regarding targeted therapy and prediction of the behavior of the tumor.

Objectives: There has been no study from Iran regarding the PDGFRA mutational analysis in GISTs. In this study, for the first time from Iran, we performed immunohistochemical and molecular analysis of PDGFRA molecule on GISTs.

METHODS

In a cross-sectional study during 7 years (2008-2014) on 50 untreated non-recurrent non-metastatic newly diagnosed GISTs, molecular analysis and immunohistochemical staining for PDGFRA were performed and findings were compared with different clinicopathological characteristics..

RESULTS

During the 7 years, 50 cases of GISTs according to the above mentioned criteria were found. 17 cases were negative for KIT mutation. Of them, 15 (30%) were positive for either exon 12 or 18 mutation of PDGFRA. These cases showed more epithelioid morphology and the number of mitotic figures were lower than PDFRA negative GISTs. Also according to the criteria for risk assessment, it seems that PDGFRA mutant GISTs are rarely in the high risk category.

CONCLUSION

PDGFRA mutant GISTs are common in Iranian population and it is recommended to perform mutation analysis for PDGFRA in every GIST with wild type KIT and epithelioid morphology.

Pediatric/"Wildtype" gastrointestinal stromal tumors

Pediatric/"Wildtype" gastrointestinal stromal tumor (P/WT-GIST) is a rare cancer, distinct and markedly different from the phenotype found predominantly in older patients (adult, non-wildtype GIST). Having a different molecular signature, it is not responsive to standard adjuvant therapies utilized in adult GIST, and surgery remains the only effective cure. However, even with presumed complete resections in patients with localized disease at presentation, recurrence rates are high. Furthermore, it is an indolent cancer that can persist for decades, and treatment strategies must balance the possible morbid risks of intervention with the reality of preserving quality of life in the interim. Effective adjuvant therapies remain elusive, and research is critically needed to identify both targets and drugs for treatment consideration.

Diagnostic and treatment strategy for small gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are considered to be potentially malignant mesenchymal tumors of the gastrointestinal tract. Clinically relevant GISTs are rare; however, subclinical GISTs (mini‐GISTs) (1‐2 cm) and pathologic GISTs (micro‐GISTs) (<1 cm) are frequently reported. Most mini‐GISTs and almost all micro‐GISTs of the stomach may exhibit benign clinical behavior, and only mini‐GISTs with high‐risk features may progress. For this review, a provisional algorithm was used to propose diagnostic and treatment strategies for patients with small GISTs. Because surgery is the only potentially curative treatment, in its application for small GISTs, the principles of sarcoma surgery should be maintained, and cost effectiveness should be considered. Indications for surgery include GISTs measuring ≥2 cm, symptomatic GISTs, and mini‐GISTs with high‐risk features (irregular borders, cystic spaces, ulceration, echogenic foci, internal heterogeneity, and tumor progression during follow‐up); however, a preoperative pathologic diagnosis is infrequently obtained. For small intestinal and colorectal GISTs, surgery is indicated irrespective of size because of their greater malignant potential. Otherwise, mini‐GISTs without high‐risk features, micro‐GISTs, and small submucosal tumors measuring <5 cm without high‐risk features may be followed by periodical endoscopic ultrasonography. Although surgical approaches and operative methods are selected according to tumor size, location, growth pattern, and surgical teams, laparoscopic surgery has produced similar oncologic outcomes and is less invasiveness compared with open surgery. After resection, pathologic examination for diagnosis and risk assessment is mandatory, and genotyping is also recommended for high‐risk GISTs. Endoscopic resection techniques, although feasible, are not routinely indicated for most mini‐GISTs or micro‐GISTs. Cancer 2016;122:3110–8. © 2016 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

Gastrointestinal stromal tumors (GISTs) are potentially malignant, and endoscopic ultrasonography and endoscopic ultrasound‐guided fine‐needle aspiration may play a major role in the diagnosis of small GISTs and submucosal tumors. Surgery is indicated for all intestinal GISTs and for small gastric GISTs in patients who have symptoms and/or high‐risk features.

Application of an individualized operative strategy for wedge resection of gastric gastrointestinal stromal tumors: Effectiveness for tumors in difficult locations

BACKGROUND

There is some concern that wedge resection of gastric gastrointestinal stromal tumors is not feasible in certain anatomic locations, such as the cardia or antrum. We sought to review our experience with treatment of gastric gastrointestinal stromal tumors with a particular focus on nonanatomic wedge resections in these challenging locations.

METHODS

Patients undergoing resection of gastrointestinal stromal tumors from 2000-2014 at the Montreal General Hospital were identified from a prospectively collected database, and outcomes were tabulated. An individualized operative strategy was used to guide resection based on tumor location, size, and characteristics. Disease-free survival and overall survival analyzed using the Kaplan-Meier method. Data are presented as median (range).

RESULTS

We identified 59 patients who underwent operative resection for gastric gastrointestinal stromal tumors. Tumor location was fundus/body/greater curvature in 35 (59%) patients, lesser curvature in 8 (14%) patients, antrum in 8 (14%) patients, and cardia in 8 (14%) patients. Median tumor size was 4.5 cm (1.4-25 cm). The majority of cardia and antral lesions were removed with wedge resections (14/16, 87%). For cardial and antral tumors, on-table gastroscopy was used to guide the operative approach and prevent narrowing of the Gastroesophageal junction or pylorus in all patients undergoing wedge resection. Negative pathologic margins were achieved in all patients. The 5-year disease-free survival was 91% and 5-year overall survival was 95%.

CONCLUSION

When selected appropriately, and under the guidance of on-table gastroscopy, laparoscopic nonanatomic wedge resection can be performed successfully in the majority of cases, even for gastrointestinal stromal tumors near the GEJ or pylorus, with excellent oncologic outcomes.

Pazopanib plus best supportive care versus best supportive care alone in advanced gastrointestinal stromal tumours resistant to imatinib and sunitinib (PAZOGIST): a randomised, multicentre, open-label phase 2 trial

BACKGROUND

Gastrointestinal stromal tumours (GIST) are the most common mesenchymal neoplasms of the gastrointestinal tract. Imatinib followed by sunitinib and regorafenib is the standard sequence of treatment for advanced disease. Pazopanib is effective in soft tissue sarcomas but has never been assessed in advanced GIST in a randomised trial. We aimed to assess the efficacy and safety of pazopanib in patients with previously treated advanced GIST.

METHODS

In this randomised, open-label phase 2 study, we enrolled adults (aged ≥18 years) with advanced GIST resistant to imatinib and sunitinib from 12 comprehensive cancer centres or university hospitals in France and randomly assigned them 1:1 using an interactive web-based centralised platform to 800 mg oral pazopanib once daily in 4-week cycles plus best supportive care or best supportive care alone. Randomisation was stratified by the number of previous treatment regimens (2 vs ≥3); no-one was masked to treatment group allocation. Upon disease progression, patients in the best supportive care group were allowed to switch to pazopanib as compassionate treatment. The primary endpoint was investigator-assessed progression-free survival, analysed by intention-to-treat. All randomised participants who received at least one dose of pazopanib were included in the safety analysis. This study is registered with ClinicalTrials.gov, number NCT01323400.

FINDINGS

Between April 12, 2011, and Dec 9, 2013, 81 patients were enrolled and randomly assigned to pazopanib plus best supportive care (n=40) or best supportive care alone (n=41). The median follow-up was 26·4 months (IQR 22·0-37·8) in the pazopanib plus best supportive care group and 28·9 months (22·0-35·2) in the best supportive care group. 4-month investigator-assessed progression-free survival was 45·2% (95% CI 29·1-60·0) in the pazopanib plus best supportive care group versus 17·6% (7·8-30·8) in the best supportive care group (hazard ratio [HR] 0·59, 95% CI 0·37-0·96; p=0·029). Median progression-free survival was 3·4 months (95% CI 2·4-5·6) with pazopanib plus best supportive care and 2·3 months (2·1-3·3) with best supportive care alone (HR 0·59 [0·37-0·96], p=0·03). 36 (88%) of the patients originally assigned to the best supportive care group switched to pazopanib following investigator-assessed disease progression; these patients had a median progression-free survival from pazopanib initiation of 3·5 months (95% CI 2·2-5·2). 55 (72%) of the 76 pazopanib-treated patients had pazopanib-related grade 3 or worse adverse events, the most common of which was hypertension (15 [38%] in the pazopanib plus best supportive care group and 13 [36%] in the best supportive care group). 20 (26%) patients had pazopanib-related serious adverse events (14 [35%] in the pazopanib plus best supportive care group and six [17%] in the best supportive care group), including pulmonary embolism in eight (9%) patients (five [13%] in the pazopanib plus best supportive care group and three [7%] in the best supportive care group). Three pazopanib-related deaths occurred (two pulmonary embolisms [one in each group] and one hepatic cytolysis [in the best supportive care group]). Three adverse event-related but not pazopanib-related deaths occurred in the best supportive care group after switch to pazopanib; these deaths were from hyperammonaemic encephalopathy, pneumopathy, and respiratory failure.

INTERPRETATION

Pazopanib plus best supportive care improves progression-free survival compared with best supportive care alone in patients with advanced GIST resistant to imatinib and sunitinib, with a toxicity profile similar to that reported for other sarcomas. This trial provides reference outcome data for future studies of targeted inhibitors in the third-line setting for these patients.

FUNDING

GlaxoSmithKline, French National Cancer Institute, EuroSARC (FP7-278742), Centre Léon Bérard.

Brunner's gland cyst in combination with gastrointestinal stromal tumor: A case report

Brunner's gland cysts are rare benign lesions that are mainly observed in the first and the second regions of the duodenum. Patients with Brunner's gland cyst demonstrate no specific symptoms. The present study reports the case of a patient with Brunner's gland cyst located in the duodenum in combination with a gastrointestinal stromal tumor (GIST) in the same region. To the best of our knowledge, the present study reports the first case of Brunner's gland cyst with GIST. A 58-year-old female patient was referred to Tianchang Hospital of Traditional Chinese Medicine (Tianchang, China) with a one-month history of upper abdominal discomfort, diarrhea and recurrent vomiting following the intake of food. Upper gastrointestinal endoscopy and a computed tomography scan revealed the presence of a round, cystic-like lesion with internal low density located within the duodenum. Pathological examination revealed that the cyst measured 0.3 cm in diameter and was consistent with a diagnosis of Brunner's gland cyst. Histopathology revealed that the cyst possessed characteristics of GIST. The patient underwent surgical exploration and tumor resection, and was discharged 2 weeks post-surgery. During the 12 month post-operative follow-up period, the outcome of the patient was good. This case study of Brunner's gland cyst combined with GIST enriches the present literature and promotes better understanding of the two diseases. Further investigation is required to explain the mechanism and association between the two rare diseases.

Bronchogenic cyst in the hepatogastric ligament masquerading as an esophageal mesenchymal tumor: a case report

Lesions occur in hepatogastric gap is common, but most of these lesions are from stomach, lower esophagus and pancreas lesions extending or transferring to the gap. Lesions occurred in the hepatogastric ligament are rare, especially bronchogenic cysts in the hepatogastric ligament. So far, there were no relevant cases reported. Here, we report a case of bronchogenic cyst in the hepatogastric ligament that masquerading as an esophageal mesenchymal tumor. A 24-year-old young man presented with abdominal bloating was diagnosed as esophageal mesenchymal tumor in previous hospital by gastroscopy, endoscopic ultrasonography (EUS) and computed tomography (CT) examination. For the sake of endoscopic submucosal dissection (ESD), the man was transferred to our hospital. During surgery, we found no lesions in lower esophagus, but external pressure ridge lesions in the distal esophagus right side wall. Then laparoscopic surgery and pathology confirmed as bronchogenic cyst in the hepatogastric ligament. We report what is, to the best of our knowledge, the first case of a bronchogenic cyst in the hepatogastric ligament masquerading as an esophageal mesenchymal tumor.