Gastrointestinal stromal tumors (GISTs) at uncommon locations: a large population based analysis

Molecular Profiling of KIT/PDGFRA-Mutant and Wild-Type Gastrointestinal Stromal Tumors (GISTs) with Clinicopathological Correlation: An 18-Year Experience at a Tertiary Center in Kuwait

In gastrointestinal stromal tumors (GISTs), identifying prototypical mutations in the KIT/PDGFRA oncogenes, or in rare alternate genes, is essential for prognostication and predicting response to tyrosine kinase inhibitors. Conversely, wild-type GISTs (WT-GIST), which lack known mutations, have limited treatment options. Data on the mutational landscape of GISTs and their impact on disease progression are very limited in Kuwait. Using a targeted next-generation sequencing panel, we investigated the spectrum and frequency of KIT, PDGFRA, and RAS-pathway-related mutations in 95 out of 200 GISTs diagnosed at Kuwait Cancer Center from 2005 to 2023 and assessed their correlation with clinicopathological parameters. Among the 200 tumors (median age 55 years; 15-91), 54% originated in the stomach, 33% in the small bowel, 7% in the colorectum, 1.5% in the peritoneum, and 4.5% had an unknown primary site. Of the 95 molecularly profiled cases, 88% had a mutation: KIT (61%), PDGFRA (25%), NF1 (2%), and one NTRK1 rearrangement. Ten WT-GISTs were identified (stomach = 6, small bowel = 2, and colorectum = 2). WT-GISTs tended to be smaller (median 4.0 cm; 0.5-8.0) (p = 0.018), with mitosis ≤5/5 mm2, and were of lower risk (p = 0.019). KIT mutations were an adverse indicator of disease progression (p = 0.049), while wild-type status did not significantly impact progression (p = 0.934). The genetic landscape in this cohort mirrors that of global studies, but regional collaborations are needed to correlate outcomes with genetic variants.

Automated machine learning for predicting liver metastasis in patients with gastrointestinal stromal tumor: a SEER-based analysis

Gastrointestinal stromal tumors (GISTs) are a rare type of tumor that can develop liver metastasis (LIM), significantly impacting the patient's prognosis. This study aimed to predict LIM in GIST patients by constructing machine learning (ML) algorithms to assist clinicians in the decision-making process for treatment. Retrospective analysis was performed using the Surveillance, Epidemiology, and End Results (SEER) database, and cases from 2010 to 2015 were assigned to the developing sets, while cases from 2016 to 2017 were assigned to the testing set. Missing values were addressed using the multiple imputation technique. Four algorithms were utilized to construct the models, comprising traditional logistic regression (LR) and automated machine learning (AutoML) analysis such as gradient boost machine (GBM), deep neural net (DL), and generalized linear model (GLM). We evaluated the models' performance using LR-based metrics, including the area under the receiver operating characteristic curve (AUC), calibration curve, and decision curve analysis (DCA), as well as AutoML-based metrics, such as feature importance, SHapley Additive exPlanation (SHAP) Plots, and Local Interpretable Model Agnostic Explanation (LIME). A total of 6207 patients were included in this study, with 2683, 1780, and 1744 patients allocated to the training, validation, and test sets, respectively. Among the different models evaluated, the GBM model demonstrated the highest performance in the training, validation, and test cohorts, with respective AUC values of 0.805, 0.780, and 0.795. Furthermore, the GBM model outperformed other AutoML models in terms of accuracy, achieving 0.747, 0.700, and 0.706 in the training, validation, and test cohorts, respectively. Additionally, the study revealed that tumor size and tumor location were the most significant predictors influencing the AutoML model's ability to accurately predict LIM. The AutoML model utilizing the GBM algorithm for GIST patients can effectively predict the risk of LIM and provide clinicians with a reference for developing individualized treatment plans.

Rectal gastrointestinal stromal tumor (GIST) in a patient with Crohn's disease: a rare coincidence case report and brief literature review

Gastrointestinal stromal tumors (GISTs) are the most common type of gastrointestinal mesenchymal tumors. The most common site for developing these neoplasms is the stomach and small intestine. In contrast, anorectal GISTs are very rare. Population-based studies have shown an increased risk of colorectal cancers (CRC) in patients with Crohn's disease (CD). As in sporadic CRC, adenocarcinomas are the most commonly observed tumor. Accordingly, it is expected that rectal mass in CD patients to be an adenocarcinoma. Some reports have presented CD cases with GISTs along the gastrointestinal tract; however, to the best of our knowledge, a rectal GIST has not been reported in CD. Herein, we report a 41-year-old woman with CD who presented with 8 weeks of constipation and was diagnosed with rectal GIST and briefly review existing reports regarding GIST in IBD.

Gastrointestinal Stromal Tumour of the Appendix: A Very Rare Entity

A 74-year-old man who presented with upper abdominal pain was found to have an incidental appendiceal mass on cross-sectional imaging. He underwent a laparoscopic appendicectomy with histopathological examination confirming a completely resected appendiceal gastrointestinal stromal tumour (GIST). Appendiceal GISTs are rare. Therefore, there is limited evidence to guide risk stratification and management with extrapolation of prognosis from data on GISTs at other sites. This paper highlights the rarity of these tumours and presents another case which correlates well with the existing but limited literature. There is a need to maintain a registry of this rare disease entity with the maintenance of longer-term follow-up data.

Pathologic Features of Primary Colon, Rectal, and Anal Malignancies

In USA, colorectal cancer is the third most commonly diagnosed cancer in men, second in women, as well as the third leading cause of cancer deaths (Siegel et al. in Cancer J Clin 73:1-112, 2023 [109]). Worldwide, colorectal cancer is the second leading cause of death and causes almost 916,000 deaths each year (Ferlay in Global cancer observatory: cancer today. International Agency for Research on Cancer, Lyon, 2020 [28]). Fortunately, due to the colon's surgical and endoscopic accessibility and functional redundancy, colorectal cancer is very treatable. Colonoscopic surveillance has the potential for not only providing tissue for the diagnosis of precancerous polyps and invasive carcinoma, but also preventing development of invasive carcinoma by the removal of precancerous lesions. This chapter discusses the clinical and pathologic features of the spectrum of epithelial, hematolymphoid, and mesenchymal malignant tumors of the colon, rectum, appendix, and anus.

Outcomes of Patients with Gastrointestinal Stromal Tumors in the Past Decade

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract (GIT) that represent approximately 1 to 2 percent of primary gastrointestinal (GI) cancers. Owing to their rarity, very little is known about their overall epidemiology, and the prognostic factors of their pathology. The current study aimed to evaluate the independent determinants of mortality in patients diagnosed with GISTs over the past decade.

METHODS

Our study comprised 2374 patients diagnosed with GISTs from 2000 to 2017 from the Surveillance, Epidemiology, and End Results (SEER) database. We analyzed the baseline characteristics, and overall mortality (OM), as well as the cancer-specific mortality (CSM) of GISTs. Variables with a p value < 0.01 in the univariate Cox regression were incorporated into the multivariate Cox model, to determine the independent prognostic factors.

RESULTS

Multivariate Cox proportional hazard regression analyses of factors affecting the all-cause mortality and GIST-related mortality among US patients between 2010 and 2017 revealed a higher overall mortality in non-Hispanic Black patients (HR = 1.516, 95% CI 1.172-1.961, p = 0.002), patients aged 80+ (HR = 9.783, 95% CI 4.185-22.868, p = 0), followed by those aged 60-79 (HR = 3.408, 95% CI 1.488-7.807, p = 0.004); male patients (HR = 1.795, 95% CI 1.461-2.206, p < 0.001); patients with advanced disease with distant metastasis (HR = 3.865, 95% CI 2.977-5.019, p < 0.001), followed by cases with regional involvement via both direct extension and lymph node involvement (HR = 3.853, 95% CI 1.551-9.57, p = 0.004); and widowed patients (HR = 1.975, 95% CI 1.494-2.61, p < 0.001), followed by single patients (HR = 1.53, 95% CI 1.154-2.028, p = 0.003). The highest CSM was observed in the same groups, except widowed patients and patients aged 60-79. The highest CSM was also observed among patients that underwent chemotherapy (HR = 1.687, 95% CI 1.19-2.392, p = 0.003).

CONCLUSION

In this updated study on the outcomes of patients with GISTs, we found that non-Hispanic Black patients, male patients, and patients older than 60 years have a higher mortality with GISTs. Furthermore, patients who have received chemotherapy have a higher GIST-specific mortality, and married patients have a lower mortality. However, we do not know to what extent these independent prognostic factors interact with each other to influence mortality. This study paves the way for future studies addressing these interactions. The results of this study may help treating clinicians to identify patient populations associated with a dismal prognosis, as those may require closer follow-up and more intensive therapy; furthermore, with married patients having a better survival rate, we hope to encourage clinicians to involve family members of the affected patients early in the disease course, as the social support might impact the prognosis.

Prognostic Nomogram for Gastrointestinal Stromal Tumors after Surgery Based on the SEER Database

We aimed to determine prognostic factors and develop an effective and practical nomogram for predicting cancer-specific survival in gastrointestinal stromal tumor (GIST) patients. Postoperative data were obtained from the SEER database (2000-2018). Patients were divided into training and validation cohorts at random (7 : 3). Prognostic factors were screened, and a prognostic nomogram was established using log-rank testing and Cox regression. We used DCA, ROC curves, C-index, and calibration curves to evaluate our model's predictive performance. The clinical value of the nomogram and the modified National Institute of Health (M-NIH) classification were compared using the NRI and IDI. The Kaplan-Meier method was applied to examine survival by risk group, and log-rank tests were applied to compare variations in survival curves. Independent prognostic risk factors associated with cancer-specific survival on multivariate Cox proportional hazards regression analysis were age, race, and tumor location, size, grade, and stage. Clinically relevant variables need to be considered in addition to statistically significant variables when developing prognostic models to aid clinical decision-making. We included two additional variables (mitotic rate and chemotherapy) when constructing the prognostic model. The C-index was 0.766 (95% confidence interval (CI): 0.737-0.794) in the training cohort and 0.795 (95% CI: 0.754-0.836) in the internal validation group suggesting robustness. The areas under the ROC curve for three-year and five-year survival were >0.700, indicating satisfactory discrimination. The calibration curves showed good agreement between the predictions of the nomogram and the actual results. The NRI (0.346 for 3-year and 0.265 for 5-year cancer-specific survival for patients with GIST (GSS) prediction; validation cohort: 0.356 for 3-year and 0.246 for 5-year GSS prediction) and IDI values (0.047 for 3-year and 0.060 for 5-year GSS prediction; validation cohort: 0.071 for 3-year and 0.084 for 5-year GSS prediction) suggested that the established nomogram performed significantly better than the M-NIH classification. The DCA indicated that the nomogram was clinically useful and had a high discriminative ability in identifying patients who were at high risk of poor outcomes. According to nomogram findings, patients were divided into three groups (high, moderate, and low risk), with significantly different prognoses in both cohorts. Our nomogram satisfactorily predicted survival in postsurgical GIST patients, which may assist clinicians to evaluate the postoperative status and guide subsequent treatments.

Development and validation of a prognostic model to predict the prognosis of patients with colorectal gastrointestinal stromal tumor: A large international population-based cohort study

Background

Colorectal gastrointestinal stromal tumors (GISTs), mesenchymal malignancy, only accounts for about 6% of GISTs, but prognosis is generally poor. Given the rarity of colorectal GISTs, the prognostic values of clinicopathological features in the patients remain unclear. Nomograms can provide a visual interface to help calculate the predicted probability of a patient meeting a specific clinical endpoint and communicate it to the patient.

Methods

We included a total of 448 patients with colorectal GISTs diagnosed between 2000 and 2019 from the Surveillance, Epidemiology, and End Results (SEER) database. For nomogram construction and validation, patients in the SEER database were divided randomly into the training cohort and internal validation cohort at a ratio of 7:3, while 44 patients with colorectal GISTs from our hospital patient data set between 2010 to 2016 served as the external validation cohort. The OS curves were drawn using the Kaplan–Meier method and assessed using the log-rank test. And, Fine and Gray’s competing-risks regression models were conducted to assess CSS. We performed univariate and multivariate analyses to select prognostic factors for survival time and constructed a predictive nomogram based on the results of the multivariate analysis.

Results

Through univariate and multivariate analyses, it is found that age, primary site, SEER stage, surgery, and tumor size constitute significant risk factors for OS, and age, primary site, histological grade, SEER stage, American Joint Committee for Cancer (AJCC) stage, surgery, and tumor size constitute risk factors for CSS. We found that the nomogram provided a good assessment of OS and CSS at 1-, 3- and 5- year in patients with colorectal GISTs. The calibration plots for the training, internal validation and external validation cohorts at 1-, 3- and 5- year OS and CSS indicated that the predicted survival rates closely correspond to the actual survival rates.

Conclusion

We constructed and validated an unprecedented nomogram to predict OS and CSS in patients with colorectal GISTs. The nomogram had the potential as a clinically predictive tool for colorectal GISTs prognosis, and can be used as a potential, objective and additional tool for clinicians in predicting the prognosis of colorectal GISTs patients worldwide. Clinicians could wield the nomogram to accurately evaluate patients’ OS and CSS, identify high-risk patients, and provide a baseline to optimize treatment plans.

Gastrointestinal Stromal Tumors (GIST): A Population-Based Study Using the SEER Database, including Management and Recent Advances in Targeted Therapy

Introduction: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasm of the gastrointestinal (GI) system. Most GISTs originate from the interstitial cells of Cajal (ICC), the pacemaker cell situated between the circular and longitudinal layers of the muscularis propria along the GI tract. In this population-based study using the SEER database, we sought to identify demographic, clinical, and pathologic factors that affect the prognosis and survival of patients with this neoplasm. Molecular genetic advances, current management guidelines, and advances in targeted therapy are discussed. Methods: Demographic and clinical data from GIST patients were retrieved from the SEER research plus database for the period 2000−2018. Statistical analysis was performed with IBM SPSS® v20.2 software using the Chi-square test, paired t-test, multivariate analysis, and Kaplan−Meier functions. Results: A total of 10,833 patients with GIST were identified. Most patients were between 60−74 years of age: 40%, Caucasian: 68%, and the male to female ratio was 1.1:1. The most common primary tumor sites were stomach: 63%, small intestine: 30%, rectum: 3%, and esophagus: 0.7%. When reported, the grade of differentiation was well: 38%, moderately: 32%, undifferentiated: 19%, poorly: 12%. The size of most tumors ranged between 6−10 cm: 36% and they were treated by surgical intervention: 82% and/or chemotherapy/targeted therapy: 39%. The stage was localized: 66%, advanced: 19%, and regional: 15%. The 5-year survival was 74% (95% confidence interval (95% CI) = 72.6−74.7), and the 5-year cause-specific survival 82% (95% CI = 80.7−82.6). The 5-year cause-specific survival by treatment included surgery at 86% (95% CI = 85.4−87.3), chemotherapy/targeted therapy with or without surgery at 77% (95% CI = 75.7−78.9), and radiation at 75% (95% CI = 74.5−80). On multivariable analysis tumor size > 5 cm, poorly and undifferentiated grade, age > 60, and distant metastases at presentation were associated with worse overall survival. Conclusion: GISTs comprise 1−2% of malignancies of the GI tract, usually affect male Caucasians between the ages of 60 and 74 years, most tumors occur in the stomach and small intestine, and are usually >5 cm, but still localized, at the time of diagnosis. Most tumors receive multimodality surgical and chemotherapy/targeted therapy treatment, with a 5-year overall survival of 74% and cause-specific survival of 82%. GIST patients would benefit from enrollment in large clinical trials to establish better therapy guidelines for unresectable, treatment-refractory, and recurrent tumors.

Ripretinib in advanced gastrointestinal stromal tumors: an overview of current evidence and drug approval

Over the past 20 years, the management of gastrointestinal stromal tumors has acted as an important model in the advancement of molecularly targeted therapies for solid tumors. The success of imatinib has established it as a lasting therapy in the management of early-stage and advanced disease in the first-line setting. Imatinib resistance inevitably develops, resulting in the need for further lines of therapy. Ripretinib is an orally administered switch-control tyrosine kinase inhibitor, specifically developed to target both primary and secondary KIT and PDGFRα resistance mutations. Herein, the authors discuss the molecular rationale, the preclinical evidence and the clinical use of ripretinib in the treatment of gastrointestinal stromal tumors in the advanced stages of disease.

Huge esophageal gastrointestinal stromal tumor successfully resected under mediastino-laparoscopic transhiatal esophagectomy: a case report

BACKGROUND

Esophageal gastrointestinal stromal tumors (E-GISTs) are often diagnosed early due to complaints such as dysphagia and are rarely found to be huge in size. Here, we report the treatment of a case of huge E-GIST successfully resected by minimally invasive surgery after neoadjuvant imatinib therapy.

CASE PRESENTATION

An 86-year-old male patient with a 3-month history of dysphagia was referred to our hospital because of a suspected mediastinal tumor on chest X-ray. The chest computed tomography scan revealed a huge solid tumor, of about 100 mm in diameter, protruding into the left thoracic cavity. Histopathological examination results of fine-needle aspiration biopsy under endoscopic ultrasonography revealed a c-kit and CD34-positive esophageal gastrointestinal stromal tumor. The patient received neoadjuvant therapy with imatinib (400 mg/day) to reduce the size of the tumor and prevent rupture during resection. After 28 days of oral administration of imatinib, the tumor size decreased. However, the patient refused to continue treatment with imatinib and therefore underwent mediastino-laparoscopic transhiatal esophagectomy. We successfully resected the tumor completely with mediastino-laparoscopic surgical techniques. Esophageal reconstruction was performed using a gastric tube in the posterior sternal route. After an uneventful postoperative course, the patient was discharged postoperative day 14. Immunohistochemical findings of the resected specimen showed that the tumor cells were positive for c-kit, DOG-1 and CD34 and negative for smooth muscle actin and S100.

CONCLUSIONS

Hybrid surgical procedure utilizing mediastino-laparoscopy might be useful for high-risk patient with esophageal tumors.

Gastrointestinal stromal tumors (GISTs) arising in uncommon locations: clinicopathologic features and risk assessment of esophageal, colonic, and appendiceal GISTs

Risk stratification of gastrointestinal stromal tumors (GISTs) is based on experience with tumors of the stomach, small bowel, and rectum, which are far more common than GISTs of other sites. In this study from 47 institutions, we analyzed GISTs of the esophagus (n = 102), colon (n = 136), and appendix (n = 27) for their size, mitotic rate, morphology, and outcome to determine which criteria predict their behavior. Esophageal GISTs were small (median: 2.5 cm) with spindle cell morphology and a low mitotic rate (mean: 3.6/5 mm²). Twelve (12%) tumors progressed, including 11 with a mitotic rate >5/5 mm² and one large (6.8 cm) GIST with a mitotic rate of 2/5 mm². Colonic GISTs were smaller (median: 1.4 cm) and presented with abdominal pain or bleeding in 29% of cases. Most (92%) were composed of spindle cells with a mean mitotic rate of 4.6/5 mm². Sixteen (12%) tumors progressed: 14 had mitotic rates >5/5 mm², and two were >5.0 cm with a mitotic rate <5/5 mm². All but one appendiceal GIST measured <2.0 cm. These tumors were composed of spindle cells with low mitotic rates (<5/5 mm²), and none progressed. Our results suggest that progression risk among esophageal and colonic GISTs is associated with increased mitotic activity (>5/5 mm²) and size >5.0 cm. These findings support the use of size and mitotic rate for prognostication of GISTs in these locations, similar to tumors of the stomach, small bowel, and rectum.

Prognostic Factors and Management of Colorectal Gastrointestinal Stromal Tumors

Introduction The gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm of the gastrointestinal tract. Even though it can be found in any location of the digestive tract, the colorectal GIST is rare. With this study, we aim to review the current knowledge regarding the prognosis and management of colorectal GIST.

Methods A literature search was conducted in PubMed, and 717 articles were collected. After analyzing these studies, 60 articles were selected to use in this review.

Results The mitotic index, as well as tumor size and location were identified as good discriminators of prognosis in various studies. Surgery remains the only curative therapy for potentially resectable tumors. However, even after surgical resection, some patients develop disease recurrence and metastasis, especially those with high-risk tumors. Therefore, surgical resection alone might be inadequate for the management of all colorectal GISTs. The discovery of GIST's molecular pathway led to a shift in its therapy, insofar as tyrosine kinase inhibitors became part of the treatment schemes for this tumor, revolutionizing the treatment's outcome and prognosis.

Discussion/Conclusion The controversy concerning colorectal GIST prognosis and treatment can be, in part, attributed to the limited number of studies in the literature. In this review, we gathered the most recent knowledge about the prognosis and management of GIST in this rare location and propose two algorithms for its approach. Lastly, we highlight the importance of an individualized approach in the setting of a multidisciplinary team.

Changing Disparity of Gastric Cancer Incidence by Histological Types in US Race-Specific Populations

Background:

The incidence pattern of gastric cancer by histological types across major race/ethnic groups is unknown.

Methods:

Age-standardized rates from 1992-2016 by race/ethnicity were calculated using data from Surveillance, Epidemiology, and End Results Program (SEER). Annual percent changes (APCs) in rates and corresponding 95% confidence intervals (CIs) were calculated and pairwise comparison of rates between race/ethnic groups was performed using the Joinpoint Regression Program. Calendar periods of incidence rates of gastric cardia and non-cardia cancer by histological types across race/ethnicity groups were shown by figures.

Results:

The White population has the highest incidence of gastric cardia adenocarcinoma and the incidence is keeping constant from 1992 through 2016 except the decreasing in the Asian population (AAPC = −1.4, 95%CI (−2.1, −0.8)). Although the incidence of non-cardia adenocarcinoma is decreasing in each group, the descending trend in the Asian population is the quickest (AAPC = −3.8, 95%CI (−4.0, −3.5)). Gastric carcinoids were observed to have statistically significant increasing trends in all race/ethnicity groups, especially in Hispanic women from 0.4 per 100,000 to 1.6 per 100,000 persons. The incidence of gastrointestinal stromal tumors (GISTs) is rising, with Non-Hispanic blacks having the highest incidence.

Conclusion:

This study demonstrated disparities in the incidence of gastric cancer by histological types among different race/ethnic groups. Further investigations are warranted to understand the changing incidence patterns by race/ethnicity.

A nationwide survey on esophageal gastrointestinal stromal tumors at accredited institutions by the Japan Esophageal Society

BACKGROUND

As esophageal gastrointestinal stromal tumors (GISTs) are very rare, their clinicopathological features remain obscure. We conducted a nationwide survey to clarify the characteristics of these tumors and to establish a consensus on their diagnosis and treatment.

METHODS

The clinicopathological information of patients with esophageal GISTs who underwent treatment between January 2010 and June 2016 at the accredited institutions by the Japan Esophageal Society was collected via a questionnaire method and analyzed statistically.

RESULTS

Fifty-one patients (29 men and 22 women; median age, 68 years) were recruited from 31 institutions. Diagnosis was triggered most frequently during screening and other disease scrutiny. Symptoms were seen only in 17 patients: highest in 11 patients with dysphagia. Thirty-five patients underwent surgery alone; 15 patients, surgery with imatinib therapy; and one patient, endoscopic resection. The tumors preferentially occurred in the lower and middle parts of the thoracic esophagus, with a median size of 36.5 mm. Neoadjuvant and adjuvant imatinib therapies were performed in seven and eight patients, respectively. Administration of imatinib 400 mg/day was the standard regimen. Postoperative follow-up observations were conducted mostly via computed tomography (CT) scans every 3 or 6 months until 5 years after surgery. The tumors recurred in ten patients within 5 years postoperatively (high risk, 38.5%; intermediate risk, 20%; low risk, 0%; very low risk, 0%; three cases of relapse with an unknown risk assessment). A patient with a high-risk GIST died from the tumor 54 months after surgery.

CONCLUSIONS

This nationwide survey revealed the current status of esophageal GISTs in Japan and provided important information for making a consensus on the treatment and follow-up method.

Gastrointestinal stromal tumor: a review of current and emerging therapies

Gastrointestinal stromal tumors (GIST) are rare neoplasms arising from the interstitial cell of Cajal in the gastrointestinal tract. Two thirds of GIST in adult patients have c-Kit mutation and smaller fractions have platelet derived growth factor receptor alpha (PDGFRA) mutation. Surgery is the only curative treatment for localized disease. Imatinib improves survival when used adjuvantly and in advanced disease. Several targeted therapies have also improved survival in GIST patients after progression on imatinib including sunitinib and regorafenib. Recently, United States Federal and Drug Administration (FDA) approved two new tyrosine kinase inhibitors for the treatment of heavily pretreated advanced/unresectable GIST including avapritinib (a selective inhibitor for PDGFRA exon 18 mutation including D842V mutations) and ripretinib (a broad-spectrum kinase inhibitor of c-Kit and PDGFRA). In this article, we will provide a comprehensive review of GIST including the current standard of care treatment and exploring future paradigm shifts in therapy.

The hybrid procedure of thoracoscopic and hand-assisted laparoscopic resection of an esophageal gastrointestinal stromal tumor: A case report

Esophageal gastrointestinal stromal tumors (E-GIST) are very rare tumors, and there is no consensus regarding the optimal surgical approach for E-GISTs. Here, we report a case of a large E-GIST that was resected via video-assisted thoracoscopic surgery (VATS) and hand-assisted laparoscopic surgery (HALS). When examining for comorbidities of myasthenia gravis using computed tomography, a 7-cm-sized tumor was detected in the lower esophagus of a 68-year-old woman. Further examination revealed the tumor to be an E-GIST with high malignant potential, and thus, esophagectomy was performed. The hybrid procedure for VATS and HALS techniques was safe and minimally invasive for this E-GIST that required esophagectomy. Thus, esophagectomy with VATS and HALS is thought to be a reasonable surgical option for resecting large E-GISTs, for which enucleation is not recommended.

Radical resection versus local excision for low rectal gastrointestinal stromal tumor: A multicenter propensity score-matched analysis

BACKGROUND

The surgical approaches and resection extent for rectal gastrointestinal stromal tumors (GISTs) are controversial due to the low incidence of this disease. A multicenter retrospective cohort study was conducted to compare the postoperative and oncologic outcomes of local excision (LE) and radical resection (RR) in patients with low rectal GIST.

PATIENTS AND METHODS

The medical records of rectal GIST patients from 11 large-scale medical centers in China (January 2000-December 2019) were reviewed. All patients were divided into either the LE group or the RR group. Propensity score matching (PSM) was conducted to reduce confounders.

RESULTS

A total of 280 patients with low rectal GIST were enrolled. After PSM, 144 patients were included (72 in each group). The LE group showed a higher anal preservation rate (100.0% vs. 76.4%, P < 0.001), shorter operation time (77.1 ± 68.4 min vs. 159.1 ± 83.6 min, P < 0.001), fewer complications (8.3% vs. 22.2%, P = 0.021) and shorter postoperative hospital stay (4.9 ± 4.1 d vs. 10.7 ± 8.1 d, P < 0.001) than the RR group. There was no significant difference in recurrence-free survival (RFS) between the RR and LE groups among patients with tumors ≤2 cm (P = 0.220), and the RR group had a superior RFS than the LE group in patients with tumors >2 cm (P = 0.046).

CONCLUSIONS

LE resulted in improved postoperative outcomes and comparable oncological safety with a low rectal GIST of ≤2 cm. However, for patients with a low rectal GIST of >2 cm, RR might be a more appropriate option with better RFS.

Neoadjuvant tyrosine kinase inhibitors in rectal gastrointestinal stromal tumours: a provision for enhanced oncological and functional outcomes

Background

The role of tyrosine kinase inhibitors (TKI) in the neoadjuvant setting and the optimal duration of therapy remains poorly defined. As such, we aim to evaluate the impact of neoadjuvant TKI on oncological and functional outcomes in our cohort of patients with rectal GISTs.

Methods

A retrospective analysis of 36 consecutive patients who underwent treatment for rectal GIST at the National Cancer Centre Singapore from February 1996 to October 2017 was analysed. Surgical, recurrence and survival outcomes between the groups who underwent neoadjuvant therapy and those who underwent upfront surgery were compared.

Results

Patients who received neoadjuvant treatment had significantly larger tumours (median size 7.1 vs. 6.0 cm, p = 0.04) and lower mitotic count (> 10 per 50 HPF, 14 vs. 70%, p = 0.03) when compared with the non-neoadjuvant group. With TKI pre-treatment (median duration 8.8 months), majority of patients (82%) achieved at least partial response to the therapy coupled with a significant downsizing effect of up to 39% (median size of 7.1–3.6 cm), resulting in similar rates of sphincter-sparing surgery (75 vs. 76%, p = 0.94) when compared with the non-neoadjuvant group. In general, neoadjuvant group had lower rates of local recurrence (0 vs. 69%, p = 0.04) and higher overall survival (7.4 vs. 5.7 years, p = 0.03) as compared to the non-neoadjuvant group.

Conclusions

Neoadjuvant TKI has the benefit of downsizing unresectable rectal GIST to benefit from sphincter-sparing procedure and also confers protection against local recurrence and improves overall survival.

A novel nomogram for predicting liver metastasis in patients with gastrointestinal stromal tumor: a SEER-based study

Background

Liver metastasis (LIM) of gastrointestinal stromal tumor (GIST) is associated with poor prognosis. The present study aimed at developing and validating nomogram to predict LIM in patients with GIST, thus helping clinical diagnosis and treatment.

Methods

The data of GIST patients derived from Surveillance, Epidemiology, and End Results (SEER) database from 2010 to 2016, which were then screened by univariate and multivariate logistic regression for the construction of LIM nomogram. The model discrimination of LIM nomogram was evaluated by concordance index (C-index) and calibration plots, while the predictive accuracy and clinical values were measured by decision curve analysis (DCA) and clinical impact plot. Furthermore, we validated predictive nomogram in the internal testing set.

Results

A total of 3797 patients were enrolled and divided randomly into training and validating groups in a 3-to-1 ratio. After logistic regression, the significant variables were sex, tumor location, tumor size, N stage and mitotic rate. The calibration curves showed the perfect agreement between nomogram predictions and actual observations, while the DCA and clinical impact plot showed the clinical utility of LIM nomogram. C-index of the nomogram was 0.812. What’s more, receiver operating characteristic curves (ROC) also showed good discrimination and calibration in the training set (AUC = 0.794, 95% CI 0.778–0.808) and the testing set (AUC = 0.775, 95% CI 0.748–0.802).

Conclusion

The nomogram for patients with GIST can effectively predict the individualized risk of liver metastasis and provide insightful information to clinicians to optimize therapeutic regimens.

Comparison of prognostic prediction models for rectal gastrointestinal stromal tumor

BACKGROUND

Rectal gastrointestinal stromal tumors (RGISTs) are biologically characterized tumors that are relatively rare. Thus, few studies have reported a specific prognostic system for this subset of tumors but integrated it into parallel systems, such as small intestine. Our aim is to develop a new predictive staging system nomogram (named FD-ZS system) for RGISTs.

RESULTS

Tumor size and mitotic rate were independent risk factors for tumor recurrence in RGISTs according to univariate and multivariate survival analyses. A prognostic predictive nomogram was developed, and a cut-off value of 65 points was calculated by X-tile to discriminate risk based on tumor size and mitotic rate. The C-indices for the FD-ZS, FD-Hou, NIH, and WHO systems were 0.706, 0.693, 0.687, and 0.680, respectively.

CONCLUSION

In the present study, a concise two-tier grading system (FD-ZS) for prognostic prediction of RGISTs that is simpler to several reported systems was developed, and a cut-off value was established to help RGIST patients determine whether to undergo adjuvant imatinib treatment.

METHODS

A nomogram was employed, and its predictive accuracy and discriminative ability were determined by concordance index (C-index) and calibration curve analyses. The nomogram was then compared with three stratification systems used for GISTs (FD-Hou, NIH, and WHO).

Gastrointestinal Stromal Tumors of the Small Intestine: Progress in Diagnosis and Treatment Research

In recent years, the diagnosis and treatment of gastrointestinal stromal tumors (GISTs) of the small intestine have been a hot topic due to their rarity and non-specific clinical manifestations. With the development of gene and imaging technology, surgery, and molecular targeted drugs, the diagnosis and treatment of GISTs have achieved great success. For a long time, radical resection was prioritized to treat GISTs of the small intestine. At present, preoperative tumor staging is a novel treatment for unresectable malignant tumors. In addition, karyokinesis exponent is the sole independent predictor of progression-free survival of GISTs. The DNA, miRNA, and protein of exosomes have also been found to be biomarkers with prognostic implications. The research on the treatment of GISTs has become a focus in the era of precision medicine, ushering in the use of standardized, normalized, and individualized treatment.

Pancreaticoduodenectomy versus limited resection for duodenal gastrointestinal stromal tumors: a systematic review and meta-analysis

Background

By comparing the long-term prognostic outcomes after pancreaticoduodenectomy (PD) and limited resection (LR), this study aimed to investigate the optimal surgical modality for duodenal gastrointestinal stromal tumors (GISTs).

Methods

Two authors independently searched PubMed, Web of Science, Embase, and the Cochrane Library for published articles comparing the long-term prognostic and clinicopathological factors of duodenal GIST patients undergoing PD versus LR. Relevant information was extracted and analyzed.

Results

After screening, 10 items comprising 623 cases were eventually included. This meta-analysis explicitly indicated that PD treatment was associated with worse long-term prognosis (hazard ratio = 1.93; 95% confidence interval [CI], 1.39–2.69; p < 0.001; I² = 0) and more complications (odds ratio [OR] = 2.90; 95% CI, 1.90–4.42; p < 0.001; I² = 10%) than LR treatment. Nevertheless, for duodenal GISTs, PD was related to the following clinicopathological features: invasion of the second part of the duodenum (OR = 3.39; 95% CI, 1.69–6.79; p < 0.001; I² = 50%), high-degree tumor mitosis (> 5/50 high-power fields; OR = 2.24; 95% CI, 1.42–3.52; p < 0.001; I² = 0), and high-risk classification (OR = 3.17; 95% CI; 2.13–4.71; p < 0.001; I² = 0).

Conclusions

Since PD is associated with worse long-term prognosis and more complications, its safety and efficacy should be ascertained. Our findings recommend the use of LR to obtain negative incision margins when conditions permit it.

Electronic supplementary material

The online version of this article (10.1186/s12893-019-0587-4) contains supplementary material, which is available to authorized users.

Gastrointestinal Stromal Tumors of the Stomach and Esophagus

Gastrointestinal stromal tumors (GISTs) arise anywhere along the gastrointestinal tract, most commonly as a result of c-kit or PDGFRA proto-oncogene mutations. Surgical resection is an important component of treatment. However, molecular profiling of GISTs has provided many insights into adjuvant and neoadjuvant therapy options. Imatinib, the most frequently studied medical therapy, has been shown in numerous studies to provide benefit to patients in both the neoadjuvant and adjuvant setting. Interval imaging is an important component of the treatment of GISTs and national surveillance recommendations should be followed.

Colonic Gastrointestinal Stromal Tumor: A Population-Based Analysis of Incidence and Survival

Objectives

The incidence of gastrointestinal stromal tumors (GISTs) located in the colon is rare. Current studies mainly focus on case reports for colonic GISTs. Therefore, a population-based analysis was useful to guide the clinical treatment strategy.

Methods

The patients were selected from 2000 to 2015 based on Surveillance, Epidemiology, and End Results (SEER) database. Patients' demographics, tumor characteristics, incidence, treatment, and survival were retrieved for analysis.

Results

249 cases of colonic GISTs were collected. The male-female ratio was close to 1 : 1 (male 51.41%, female 48.59%). Most cases were Caucasians (70.28%), and African Americans accounted for 19.68%. Age of diagnosis ranged from 21 to 93 years with a median (mean) age of 67.5 (65.56). The incidence was rare, only 0.018 per 100,000. It had an annual percentage change (APC = -0.7728) without statistical significance (P = 0.5127) while the incidence of other GISTs increased from 2000 to 2015, with an annual percentage change of 3.9% (P = 0.0001). Surgery was associated with better prognosis whereas chemotherapy did not impact the survival rate.

Conclusion

Colonic GIST is a rare solid tumor, and the incidence is stable. The entity has a poorer prognosis than other GISTs. Surgery improved the survival rate, while chemotherapy did not.

Establishment and Verification of Prognostic Nomograms for Patients with Gastrointestinal Stromal Tumors: A SEER-Based Study

With gastrointestinal tract as the origin, gastrointestinal stromal tumor (GIST) is recognized as the very widespread mesenchymal tumor. A precise prognostic model of survival is required to guide the treatment options of patients with GIST. This study was designed to map the overall survival (OS) and cancer-specific survival (CSS) of GIST patients. According to the Surveillance, Epidemiology, and End Results (SEER) program database, we acquired the data of 6,713 patients with GIST who were diagnosed between 2004 and 2014. We randomly separated the patients into training (n = 4,699) and validation (n = 2,014) groups. To assess the prognostic impact of multiple clinical parameters, the Kaplan-Meier approach and the Cox proportional hazards regression model were adopted, where essential prognostic variables were combined to create nomograms. The consistency index and curve of calibration had been adopted to assess nomogram discrimination ability and prediction accuracy. A multifactor analysis of the training cohort showed that age, gender, size of tumor, location, and primary surgery were remarkably related to survival, and these variables were applied to create nomograms. The nomogram demonstrated excellent accuracy in estimating 2-, 3-, and 5-year OS and CSS, with a C-index of 0.740 (95% confidence interval [CI], 0.723-0.757) for OS and 0.743 (95% CI, 0.718-0.768) for CSS. In the validation cohort, the nomogram-predicted C-index was 0.741 for OS (95%CI, 0.717-0.765) and 0.746 (95%CI, 0.713-0.779) for CSS. All calibration curves showed good consistency between predicted and actual survival. A new nomogram was created and verified to predict the OS and CSS of patients with GIST. These new prognostic models can help enhance the accuracy of survival outcome predictions, thus facilitating to provide constructive therapeutic suggestions.

A large national comparative study of clinicopathological features and long-term survivals between esophageal gastrointestinal stromal tumor and leiomyosarcoma

BACKGROUND

Esophageal gastrointestinal stromal tumors (E-GIST) and leiomyosarcoma (E-LMS) are rare tumors. Previous studies are limited to small number of patients. We sought to study these two tumors using a large national database.

METHODS

The National Cancer Data Base 2004-2014 was queried for patients with E-GIST and E-LMS. The primary outcome was overall survival (OS). Univariate and multivariable Cox regression models were used to investigate OS predictors.

RESULTS

We found 141 E-GIST and 38 E-LMS patients, with esophagectomy and systemic treatment rate of 55% and 49% for E-GIST and 50% and 26% for E-LMS. The 5-year OS of E-GIST and E-LMS were 62% and 23%, respectively, p < 0.001. In multivariable analysis, young age, tumor <10 cm, esophagectomy, and E-GIST were associated with superior OS. There was a higher median and mean OS with neoadjuvant vs. upfront surgery for E-GIST group (98 and 111 vs 79 and 80 months).

CONCLUSION

E E-GIST has superior OS compared to E-LMS. Esophagectomy is the cornerstone treatment modality. Further studies are needed to evaluate the role of neoadjuvant therapy in E-GIST patients.

Clinicopathologic features and outcomes of gastrointestinal stromal tumors arising from the esophagus and gastroesophageal junction

Background

Our aim was to characterize the clinicopathological features and outcomes of gastrointestinal stromal tumors (GISTs) arising from the esophagus and gastroesophageal junction (GEJ) and describe the survival of patients treated at our institution as well as from a national hospital-based registry.

Methods

Twenty-eight cases were identified using the Mayo Clinic Cancer Registry from 1997 to 2016, and 1,010 cases from the National Cancer Database (NCDB) between 2004 and 2014, with analysis of TNM staging, histopathological features, mitotic index, immunohistochemical studies, and KIT mutational analysis.

Results

At Mayo Clinic, the tumors ranged in size from 0.3-13 cm (mean 5.40 cm). IHC results were: CD117 (KIT) in 100% (23/23 cases) and DOG1 in 100% (6/6), followed by CD34 (85.7%, 12/14), smooth muscle actin (27.8%, 5/18), desmin (18.2%, 2/11), and S-100 protein (13.3%, 2/15). Mutational analysis (performed in 10 cases) showed KIT exon 11 mutations in 8 cases; KIT mutation was not identified in 2 cases (presumed wild-type). Two-thirds of patients underwent surgery, of which 70% had an esophagectomy. Fourteen patients received adjuvant imatinib mesylate. Five patients had liver metastases at the time of diagnosis; none had lymph node metastases. A total of 38.9% of cases had recurrent or metastatic disease. Complete clinical follow-up was available for 10 patients (median follow-up duration 31.5 months; range, 10-145 months): one (male) had a local recurrence at the anastomotic site and one (female) suffered a liver metastasis; the others were either disease-free or had stable disease at the time of last follow-up. There was a significant association seen among metastatic disease and mitotic count >5/50 high-powered field (HPF) (P=0.016), with median mitotic rate 90/50 HPF (range, 7-500) for metastatic tumors versus 6/50 HPF (range, 0-100) for non-metastatic tumors. For metastatic disease, median tumor size was 7.3 cm (range, 1-66 cm) compared to 4.8 cm (range, 0.02-71 cm) for non-metastatic disease, which was also statistically significant (P≤0.0001). Two hundred and fifty-eight NCDB cases were risk stratified using the Joensuu criteria. Among 89 low risk category tumors, only 2 (2.2%) were ultimately metastatic. A total of 10.9% (15/138) of high risk category tumors were metastatic. The median overall survival (OS) from the time of diagnosis for the Mayo Clinic cohort was 129.5 months (95% CI, 55.7-not reached), with 5-year OS 85.7%. Median OS for the NCDB cohort was 135.95 months (95% CI, 104.08-not reached) with 5-year OS 68.2%. Superior OS was seen in females (HR 0.67, 95% CI, 0.49-0.89, P=0.006).

Conclusions

Among esophageal and GEJ GISTs, metastatic disease was associated with increased mitotic count and increased tumor size. Men were found to have inferior OS. The Joensuu risk criteria were validated for risk stratification of esophageal and GEJ GISTs.

Gastrointestinal stromal tumors: A multidisciplinary challenge

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors located in the alimentary tract. Its usual manifestation is gastrointestinal bleeding. However, small asymptomatic lesions are frequently detected as incidental finding. Characteristically, most GISTs (> 95%) are positive for the KIT protein (CD117) by IHC staining and approximately 80%-90% of GISTs carry a mutation in the c-KIT or PDGFRA genes. Mutational analysis should be performed when planning adjuvant and neoadjuvant therapy, due to its possible resistance to conventional treatment. The arise of tyrosine kinase inhibitor has supposed a revolution in GISTs treatment being useful as adjuvant, neoadjuvant or recurrence disease treatment. That is why a multidisciplinary approach to this disease is required. The correct characterization of the tumor at diagnosis (the diagnosis of recurrences and the evaluation of the response to treatment with tyrosine kinase inhibitors) is fundamental for facing these tumors and requires specialized Endoscopist, Radiologists and Nuclear Medicine Physician. Surgery is the only potentially curative treatment for suspected resectable GIST. In the case of high risk GISTs, surgery plus adjuvant Imatinib-Mesylate for 3 years is the standard treatment. Neoadjuvant imatinib-mesylate should be considered to shrink the tumor in case of locally advanced primary or recurrence disease, unresectable or potentially resectable metastasic tumors, and potentially resectable disease in complex anatomic locations to decrease the related morbidity. In the case of Metastatic GIST under Neoadjuvant treatment, when there are complete response, stable disease or limited disease progression, complete cytoreductive surgery could be a therapeutic option if feasible.

Distinctive features of gastrointestinal stromal tumors arising from the colon and rectum

Background

Colon and rectal gastrointestinal stromal tumors (GISTs) are rare and poorly characterized. Because the majority of treatment guidelines for GISTs are extrapolated from tumors of gastric and small bowel origin, our aim was to better characterize the unique clinicopathologic features and prognostic factors of colon and rectal GISTs to guide clinical care.

Methods

The National Cancer Data Base (NCDB) was queried from 2006 to 2013 for cases of GISTs in the stomach, colon, and rectum. Patient demographics, clinical characteristics, and survival were compared.

Results

A total of 11,302 gastric GISTs were compared to 398 colon and 393 rectal GISTs. After propensity matching, compared to gastric GISTs, rectal GISTs had improved overall survival (HR =0.695, P=0.0264), while colon GISTs had worse overall survival (HR =1.6, P=0.0005). Surgical treatment for rectal GISTs was more likely to be local excision compared to colonic GISTs (51.1% vs. 8.4%, P<0.0001). Colon and gastric GISTs were less likely to receive systemic therapy compared to rectal GISTs (34.2% vs. 34.0% vs. 55.2%, P<0.0001). Adjuvant systemic therapy conveyed a survival advantage to rectal GISTs (HR =0.47, P=0.042) but not colon GISTs. There was a negative impact of adjuvant therapy on survival for colon GISTs <5 cm (HR =3.41, P=0.032).

Conclusions

Patients with rectal GISTs live longer than those with colon and gastric GISTs, and adjuvant therapy prolongs their survival. Many patients with colon GISTs are treated with adjuvant therapy despite a detrimental effect on survival. Tumor biology of colon and rectal GISTs needs to be better studied to tailor treatment.

Gastrointestinal stromal tumor of the esophagus: current issues of diagnosis, surgery and drug therapy

Gastrointestinal stromal tumors (GISTs) often arise in the stomach and small intestine, while esophageal GISTs are rare. Due to their rarity, clinicopathological data on esophageal GISTs are extremely limited, and this results in a lack of clear recommendations concerning optimal surgical management for esophageal GISTs. It is difficult to distinguish esophageal GIST from leiomyoma, the most frequent esophageal mesenchymal tumor, prior to resection, because the two types of tumors appear similar on computed tomography (CT), endoscopic ultrasound (EUS), and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). Fine-needle aspiration biopsy (FNAB) under EUS enables definitive diagnosis, but it is often avoided because scarring could make enucleation more difficult and increase the risk of tumor dissemination by capsule destruction. Esophageal segmental and wedge resections are not usually performed due to the anatomical peculiarity of the esophagus, and the surgical options are limited to the highly invasive esophagectomy or the much less invasive surgical tumor enucleation. The decision as to which surgical procedure should be performed for esophageal GISTs is still under debate. Tumor enucleation may be permitted for smaller tumors, and esophagectomy may be recommended for larger GISTs or high-risk tumors with a high mitotic rate. The purpose of neoadjuvant imatinib administration is downsizing of the GIST to reduce the extent of resection and to reduce the risk of intraoperative complications, including tumor rupture. The efficacy of neoadjuvant/adjuvant imatinib therapy for esophageal GISTs is poorly understood, because the reports are limited to case reports or case series with small numbers. More clinicopathological data and clinical trials for esophageal GIST are expected.

Management of esophageal gastrointestinal stromal tumor: review of one hundred seven patients

Gastrointestinal stromal tumors (GIST) are the most common type of gastrointestinal mesenchymal tumor, but are rarely found in the thoracic esophagus. There is no clear consensus about the optimal treatment of this rare disease. A systematic search of the literature was performed for localized esophageal GIST that was resected between 2000 and 2015, and individual patients were included from two major academic institutions. We obtained information on demographics, tumor size and location, mitotic rate, treatment method, and time to recurrence or death. We performed univariate and multivariate Cox regression analyses to evaluate the factors associated with recurrence or death. A total of 28 studies met our inclusion and exclusion criteria, and with two patients from two academic institutions, we had a total of 107 patients in the study. Due to lack of uniformity among studies, there were several missing data for different variables. The average patient age was 56 (n = 98) with mostly males (60%, n = 91). The average tumor size on the CT scan was 7.9 ± 5.4 cm (n = 91), located mostly in the distal esophagus (81%, n = 74). A similar number of patients underwent enucleation (n = 47) compared to esophagectomy (n = 42). Approximately half of the patients had a mitotic rate of 0-4 mitosis per 50 high-powered field (48%, n = 80). The median survival time was 73 months with a 5-year disease free survival of 57% (n = 97). Univariate Cox regression analyses showed that a large tumor, undergoing esophagectomy, and a high mitotic rate were associated with poor survival or recurrence control. We found that patients with a lesion smaller than or equal to 5 cm on the CT scan had a better disease-free survival rate than those with a size greater than 5 cm (HR = 12.41, p = 0.014) and had a 5-year survival rate of 92% with 90% of those patients undergoing enucleation (n = 29). Esophageal GIST is a very rare malignancy. The tumor size and mitotic rate of the tumor are associated with poor survival. However, patients with esophageal GIST measuring 5 cm or smaller may be safely treated with esophageal enucleation.

Gastric and small intestine gastrointestinal stromal tumors: Do outcomes differ?

BACKGROUND AND OBJECTIVES

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Previous literature has suggested that small intestine GISTs are more aggressive than gastric GISTs. Our primary objective was to compare the outcomes of gastric and small intestine GISTs in the decade after approval of imatinib for treatment.

METHODS

The SEER database was queried for cases of gastric and small intestine GIST between the years 2002 and 2012, using the ICD-O-3 histology code 8936. Survival analysis was performed using generalized gamma models for time to cause-specific mortality (CSM).

RESULTS

CSM was 14.0% for the 3,759 gastric GIST patients and 14.3% for the 1,848 small intestine GIST patients. Five-year survival was 82.2% and 83.3% for gastric and small intestine patients, respectively. The number of diagnosed cases of GIST increased over the course of this study, especially for tumors <5 cm in size and in patients over age 50 years.

CONCLUSIONS

In this large nation-wide study, we found that patients with gastric and small intestine GISTs had similar outcomes, in contrast to previous reports. The diagnosis of GIST has significantly increased in the last decade, which may reflect the increased recognition of this entity and frequent use of imaging. J. Surg. Oncol. 2017;115:351-357. © 2016 Wiley Periodicals, Inc.

[Obscure gastrointestinal bleeding due to gastrointestinal stromal tumors]

BACKGROUND

The gastrointestinal stromal tumours (GIST) are the most common soft tissue sarcomas of the digestive tract. They are usually found in the stomach (60-70%) and small intestine (25-30%) and, less commonly, in the oesophagus, mesentery, colon, or rectum. The symptoms present at diagnosis are, gastrointestinal bleeding, abdominal pain, abdominal mass, or intestinal obstruction. The type of symptomatology will depend on the location and size of the tumour. The definitive diagnosis is histopathological, with 95% of the tumours being positive for CD117.

CLINICAL CASES

This is an observational and descriptive study of 5cases of small intestinal GIST that presented with gastrointestinal bleeding as the main symptom. The period from the initial symptom to the diagnosis varied from 1 to 84 months. The endoscopy was inconclusive in all of the patients, and the diagnosis was made using computed tomography and angiography. Treatment included resection in all patients. The histopathological results are also described.

CONCLUSION

GIST can have multiple clinical pictures and unusual symptoms, such as obscure gastrointestinal bleeding. The use of computed tomography and angiography has shown to be an important tool in the diagnosis with patients with small intestine GISTs.

Pathologic Features of Primary Colon, Rectal, and Anal Malignancies

In the United States, colorectal cancer is the third most commonly diagnosed cancer in both men and women, as well as the third leading cause of cancer deaths (Colorectal cancer facts & figures 2014–2016, 2014 [2]). Worldwide, colorectal cancer is the fourth leading cause of death and causes almost 700,000 deaths each year (Cancer: fact sheet No. 297, 2015 [55]). This chapter discusses the clinical and pathologic features of the spectrum of epithelial, hematolymphoid, and mesenchymal malignant tumors of the colon, rectum, appendix, and anus.

Beyond standard therapy: drugs under investigation for the treatment of gastrointestinal stromal tumor

INTRODUCTION

Gastrointestinal stromal tumor (GIST) is the most common nonepithelial malignancy of the GI tract. With the discovery of KIT and later platelet-derived growth factor α (PDGFRA) gain-of-function mutations as factors in the pathogenesis of the disease, GIST was the quintessential model for targeted therapy. Despite the successful clinical use of imatinib mesylate, a selective receptor tyrosine kinase (RTK) inhibitor that targets KIT, PDGFRA and BCR-ABL, we still do not have treatment for the long-term control of advanced GIST.

AREAS COVERED

This review summarizes the drugs that are under investigation or have been assessed in trials for GIST treatment. The article focuses on their mechanisms of actions, the preclinical evidence of efficacy, and the clinical trials concerning safety and efficacy in humans.

EXPERT OPINION

It is known that KIT and PDGFRA mutations in GIST patients influence the response to treatment. This observation should be taken into consideration when investigating new drugs. RECIST was developed to help uniformly report efficacy trials in oncology. Despite the usefulness of this system, many questions are being addressed about its validity in evaluating the true efficacy of drugs knowing that new targeted therapies do not affect the tumor size as much as they halt progression and prolong survival.