Immunophenotype, proliferation, DNA ploidy, and biological behavior of gastrointestinal stromal tumors: a multivariate clinicopathologic study

Atypical Mitotic Figures Are Prognostically Meaningful for Canine Cutaneous Mast Cell Tumors

Cell division through mitosis (microscopically visible as mitotic figures, MFs) is a highly regulated process. However, neoplastic cells may exhibit errors in chromosome segregation (microscopically visible as atypical mitotic figures, AMFs) resulting in aberrant chromosome structures. AMFs have been shown to be of prognostic relevance for some neoplasms in humans but not in animals. In this study, the prognostic relevance of AMFs was evaluated for canine cutaneous mast cell tumors (ccMCT). Histological examination was conducted by one pathologist in whole slide images of 96 cases of ccMCT with a known survival time. Tumor-related death occurred in 11/18 high-grade and 2/78 low-grade cases (2011 two-tier system). The area under the curve (AUC) was 0.859 for the AMF count and 0.880 for the AMF to MF ratio with regard to tumor-related mortality. In comparison, the AUC for the mitotic count was 0.885. Based on our data, a prognostically meaningful threshold of ≥3 per 2.37 mm2 for the AMF count (sensitivity: 76.9%, specificity: 98.8%) and >7.5% for the AMF:MF ratio (sensitivity: 76.9%, specificity: 100%) is suggested. While the mitotic count of ≥ 6 resulted in six false positive cases, these could be eliminated when combined with the AMF to MF ratio. In conclusion, the results of this study suggests that AMF enumeration is a prognostically valuable test, particularly due to its high specificity with regard to tumor-related mortality. Additional validation and reproducibility studies are needed to further evaluate AMFs as a prognostic criterion for ccMCT and other tumor types.

Differential Diagnosis and Molecular Stratification of Gastrointestinal Stromal Tumors on CT Images Using a Radiomics Approach

Treatment planning of gastrointestinal stromal tumors (GISTs) includes distinguishing GISTs from other intra-abdominal tumors and GISTs’ molecular analysis. The aim of this study was to evaluate radiomics for distinguishing GISTs from other intra-abdominal tumors, and in GISTs, predict the c-KIT, PDGFRA, BRAF mutational status, and mitotic index (MI). Patients diagnosed at the Erasmus MC between 2004 and 2017, with GIST or non-GIST intra-abdominal tumors and a contrast-enhanced venous-phase CT, were retrospectively included. Tumors were segmented, from which 564 image features were extracted. Prediction models were constructed using a combination of machine learning approaches. The evaluation was performed in a 100 × random-split cross-validation. Model performance was compared to that of three radiologists. One hundred twenty-five GISTs and 122 non-GISTs were included. The GIST vs. non-GIST radiomics model had a mean area under the curve (AUC) of 0.77. Three radiologists had an AUC of 0.69, 0.76, and 0.84, respectively. The radiomics model had an AUC of 0.52 for c-KIT, 0.56 for c-KIT exon 11, and 0.52 for the MI. The numbers of PDGFRA, BRAF, and other c-KIT mutations were too low for analysis. Our radiomics model was able to distinguish GISTs from non-GISTs with a performance similar to three radiologists, but less observer dependent. Therefore, it may aid in the early diagnosis of GIST, facilitating rapid referral to specialized treatment centers. As the model was not able to predict any genetic or molecular features, it cannot aid in treatment planning yet.

Multiple mathematical models of diffusion-weighted imaging for endometrial cancer characterization: Correlation with prognosis-related risk factors

PURPOSE

To investigate mono-exponential, bi-exponential, and stretched-exponential models of diffusion-weighted imaging (DWI) for evaluation of prognosis-related risk factors of endometrial cancer (EC).

METHOD

Sixty-one consecutive patients with EC who preoperatively underwent pelvic MRI with multiple b value DWI between September 2016 and May 2018 were enrolled. The apparent-diffusion-coefficient (ADC), bi-exponential model parameters (D, D* and f) and stretched-exponential model parameters (DDC and α) were measured and compared to analyze the following prognosis-related risk factors confirmed by pathology: histological grade, depth of myometrial invasion, cervical stromal infiltration (CSI) and lymphovascular invasion (LVSI). A stepwise multilvariate logistic regression and the receiver operating characteristic (ROC) curves were performed for further statistical analysis.

RESULTS

Lower ADC, D, f, and DDC were observed in tumor with high grade compared with a low-grade group, and the largest area under curve (AUC) was obtained when combining f and DDC values. ADC, D, f, DDC, and α were significantly different in patients with deep myometrial invasion (DMI) compared to those without DMI; the combination of f, DDC and α showed the highest AUC. Significantly different ADC and f were found between patients' presence and absence CSI; the f values showed the highest diagnostic performance with an AUC of 0.825. Regarding the LVSI, ADC, D*, f, and DDC were significantly lower in tumors with LVSI compared to those without LVSI; the combination of f and DDC showed the largest AUC.

CONCLUSION

Multiple mathematical DWI models are a useful approach for the prediction of prognosis-related risk factors in EC.

Utility of the relative apparent diffusion coefficient for preoperative assessment of low risk endometrial carcinoma

OBJECTIVES

Lymphadenectomy is not recommended for low risk stage I endometrial carcinoma (EC) patients. This study was to investigate the predictive value of apparent diffusion coefficient (ADC) values in predicting patients with low risk EC, and to identify an optimum ADC measurement for preoperative assessment.

MATERIALS AND METHODS

Eighty-one patients with stage I EC who underwent diffusion-weighted imaging (DWI) at 1.5T were included and divided into low group and intermediate-high risk group based on the ESMO-ESGO-ESTRO classification. Clinical indexes, conventional MRI parameters, minimum ADC values (minADC), mean ADC values (meanADC) and relative ADC values (rADC) were compared between those two groups. rADC was calculated using the equation ADC (cancer)/ADC (reference) with the obturator internus muscle as reference. The optimal ADC measurement and cut-off ADC value for low risk EC were calculated using the receiver operating characteristic (ROC) curve.

RESULTS

The low risk group had significantly higher meanADC, minADC, and rADC values than did the intermediate-high risk group (1.095 vs. 0.902 × 10^-3 mm²/s, 0.755 vs. 0.657 × 10^-3 mm²/s, 0.754 vs. 0.603, respectively). In assessments of low risk EC patients, the area under the curve (AUC) values for meanADC, minADC, and rADC were 0.840 (95%CI, 0.749,0.931), 0.681 (95% CI: 0.561,0.800), and 0.876(95% CI: 0.798,0.954), respectively. The optimal cut-off rADC value for prediction was 0.669, the maximum Youden index, sensitivity, specificity, and accuracy values were 0.683, 81.8%, 86.5%, and 84.0%, respectively.

CONCLUSIONS

rADC is superior to minADC and meanADC for predicting patients with low risk EC, and could potentially aid to the surgical management of these patients in avoiding unnecessary lymphadenectomy.

Clinical Presentation and Treatment of Gastrointestinal Stromal Tumors

Aims and background

Gastrointestinal stromal tumors (GISTs), although rare, are the most common mesenchymal neoplasms affecting the gastrointestinal tract. We present our experience in the treatment of localized and metastatic disease and a review of literature.

Patients and methods

Nine patients were observed from April 2002 to July 2004. Eight tumors were in the gastric area and J was in the small bowel. In 5 cases, complete surgical removal was performed, and none of these patients underwent adjuvant therapy. The remaining 4 cases, with locally advanced or recurrent disease, were treated with imatinib.

Results

The patients with localized disease treated only by surgery did not relapse. In the patients with locally advanced or metastatic disease treated by imatinib, we observed 3 partial responses, and one case was not assessable because he had no measurable disease. In 2 of 3 responders, it was possible to perform a new radical surgery.

Conclusions

Our series is too small to draw any conclusion. According to our review of the literature, surgery remains the standard treatment for non-metastatic GISTs. Imatinib mesylate represents a major breakthrough in the treatment of advanced GISTs and is the first effective systemic therapy for the disease.

Endometrial carcinoma: diffusion-weighted imaging diagnostic accuracy and correlation with Ki-67 expression

AIM

To evaluate the role of diffusion-weighted imaging (DWI) in the detection of endometrial carcinoma and to correlate the apparent diffusion coefficient (ADC) value with Ki-67 expression.

MATERIALS AND METHODS

Fifty-two patients with invasive cancer who underwent pelvic MRI were prospectively evaluated using DWI with b-values of 0 and 1000 s/mm^2.The ADC values from standard DWI were measured. The expression of Ki-67 in histological specimens was analysed using immunohistochemistry. The ADC values of endometrial carcinoma and normal endometrial parenchyma were compared. Relationships between ADC values and Ki-67 expression were determined using Wilcoxon's signed rank test and the Kruskal-Wallis test.

RESULTS

Endometrial carcinoma was detected at DWI as a hyperintense area in 92.3% (48/52) of patients. There was a significant difference in the mean ADC values between endometrial carcinoma and normal endometrial parenchyma (1.39±0.27×10^-3 versus 0.93±0.21×10^-3 mm²/s, p<0.001). The mean ADC values of grade 1 patients were significantly higher than those of grade 3 patients (1.01±0.16×10^-3 versus 0.83±0.21×10^-3 mm²/s, p<0.05). The mean ADC values of stage IB patients were significantly lower than those of stage IA patients (0.86±0.16×10^-3 versus 1.04±0.21×10^-3 mm²/s, p<0.01). The mean ADC values of high Ki-67 expression patients were significantly lower than those of low Ki-67 expression patients (0.82±0.12×10^-3 versus 1.16±0.12×10^-3 mm²/s, p<0.001). There was a significant negative correlation between the mean ADC value and Ki-67 expression (r=-0.82, p<0.001).

CONCLUSION

The ADC value was a helpful parameter for detecting the tumour grade, stage, and proliferation of endometrial carcinoma, and may further improve patient prognosis and contribute to the development of more effective treatment programmes.

Thymosin beta-4 overexpression correlates with high-risk groups in gastric gastrointestinal stromal tumors: A retrospective analysis by immunohistochemistry

BACKGROUND

Thymosin beta-4 (Tβ4) is a protein that is linked to a number of important biological actions and recently tumor progression and poor prognosis of some tumors. The aim of this study was to evaluate Tβ4 expression in gastric GISTs and correlate with some clinicopathological characteristics related with prognosis and clinical outcome in order to add further data to the current literature.

METHODS

Tβ4 antibody was applied to the 4μm-thick paraffin sections of 57 gastric GISTs by immunohistochemistry.

RESULTS

Tβ4 expression was found to be directly corrrelated with higher risk groups, tumor size, mitotic count, cellularity, and necrosis while it was inversely correlated with overall survival (OS) by univariate analysis (p=0.000, p=0.001, p=0.000, p=0.025, p=0.023, and p=0.042, respectively). The direct association between Tβ4 expression and risk groups were also supported by multivariate analysis (p=0.000, β=0.497, t=4.374).

CONCLUSION

Overexpression of Tβ4 was found to be related with predictive characteristics for tumor progression and adverse prognosis. Thus, we suggest that overexpression of Tβ4 might play a role in the progression of gastric GISTs and might be used as a potential prognostic tool as well as a target for novel therapies.

Diffusion kurtosis imaging for differentiating between the benign and malignant sinonasal lesions

PURPOSE

The study aimed to evaluate diffusion kurtosis imaging (DKI) in the differentiation between benign and malignant sinonasal lesions, and to compare the diagnostic performance of DKI with diffusion weighted imaging (DWI).

MATERIALS AND METHODS

Eight-one patients with solid sinonasal lesions confirmed by surgery and pathology (46 malignant and 35 benign) underwent conventional MRI, DWI, and DKI. DKI was performed employing a 13 extended b-value ranging from 0 to 2500 s/mm² . Apparent diffusion coefficient (ADC) from DWI, kurtosis (K), and diffusion coefficient (D) from DKI were measured and compared between two groups.

RESULTS

ADC and D values were significantly lower in the malignant sinonasal lesions than in the benign sinonasal lesions (1.11 ± 0.41 versus 1.58 ± 0.50 × 10^-3 mm² /s and 1.45 ± 0.36 versus 2.03 ± 0.49 × 10^-3 mm² /s, respectively, both P < 0001). K value was significantly higher in the malignant lesions than in the benign lesions (0.91 ± 0.23 versus 0.57 ± 0.24, P < 0001). The receiver operating characteristic curve analyses yielded a cutoff ADC value of 1.27 × 10^-3 mm² /s for differentiating between benign and malignant lesions, with a sensitivity of 69.6%, a specificity of 77.1% and an accuracy of 74.0%; a cutoff D value of 1.75 × 10^-3 mm² /s, with a sensitivity of 82.6%, a specificity of 77.1% and an accuracy of 80.2%; a cutoff K value of 0.63 with a sensitivity of 95.7%, a specificity of 77.1% and an accuracy of 87.7%. The area under the curve of K value was significantly larger than that of ADC value (0.875 versus 0.762; P < 0.05).

CONCLUSION

K value of DKI demonstrates significantly higher accuracy compared with ADC value for the differentiation between benign and malignant sinonasal lesions. DKI may be a noninvasive method to evaluate the sinonasal lesions.

LEVEL OF EVIDENCE

1 J. MAGN. RESON. IMAGING 2017;45:1446-1454.

Ki-67 Labeling Index can be used as a Prognostic Marker in Gastrointestinal Stromal Tumor: A Systematic Review and Meta-Analysis

Purpose

The aim of this study was to investigate the prognostic relevance of the Ki-67 labeling index (LI) in gastrointestinal stromal tumor (GIST) through a systematic review, meta-analysis and diagnostic test accuracy review.

Method

The study included 1,967 GIST cases from 24 eligible studies. We investigated the correlation between high Ki-67 LI and survival and the proper criteria for high Ki-67 LI. In addition, a diagnostic test accuracy review was conducted to evaluate the predictive role of high Ki-67 LI for higher risk of tumor recurrence.

Results

A high Ki-67 LI was significantly correlated with worse disease-free survival (DFS) (hazard ratio [HR] 3.658, 95% confidence interval [CI] 2.687-4.979, p<0.001) and overall survival (OS) (HR 3.730, 95% CI 2.819-4.936, p<0.001). With regard to DFS and OS, the subgroup with a cutoff value of >4% for high Ki-67 LI had a higher HR than the subgroup with a ≤4% cutoff. In the diagnostic test accuracy review, a high Ki-67 LI was significantly correlated with higher risk of tumor recurrence (pooled sensitivity = 0.44, pooled specificity = 0.87, area under the curve on the summary receiver operating characteristic curve = 0.656).

Conclusions

Our results showed that a high Ki-67 LI was significantly correlated with worse prognosis and higher risk of tumor recurrence in GIST. Further prospective studies of the prognostic role of Ki-67 LI are necessary prior to application in clinical practice.

Back to the start: Evaluation of prognostic markers in gastrointestinal stromal tumors

The aim of this study was to provide a standardized risk stratification model for gastrointestinal stromal tumors (GISTs) based on tumor localization, tumor size, involved lymph nodes and metastases, as well as mitotic activity and other morphological and molecular markers, in order to improve the risk evaluation scheme for recurrence, metastatic spread and survival for patients with GIST. A total of 201 cases of patients with GIST were investigated according to standardized morphological markers, including nuclear pleomorphism, tumor cell necrosis, mucosal infiltration, ulceration, skeinoid fibers and growth pattern. In addition, all cases were immunohistochemically analyzed using a tissue microarray platform for various markers of differentiation (CD34, CD44, CD117, desmin, discovered on GIST 1, platelet-derived growth factor receptor α, S-100 and smooth muscle actin) and proliferation (B-cell lymphoma 2, P16, P53, phosphohistone H3 and Ki-67). These findings were correlated by uni- and multivariable analyses with clinicopathological characteristics, including recurrence, metastasis and survival. The general clinicopathological parameters of this GIST specimen cohort were comparable to previous studies. While several parameters exhibited clear associations to each other and to the defined clinical endpoints, the multivariate analysis reduced the number of relevant prognostic variables to localization, margin status, growth pattern and hematoxylin and eosin-based mitosis/Ki-67-based proliferation of GISTs. With the exception of CD34, none of the applied markers of differentiation and proliferation were found to be independent prognostic markers in GIST and the classical risk factors of GIST remain important prognostic factors. Additionally, growth pattern may predict the risk of recurrence and metastasis in GIST patients. Additional independent molecular prognostic markers remain to be identified and validated.

Current management of patients with gastrointestinal stromal tumor receiving the multitargeted tyrosine kinase inhibitor sunitinib

BACKGROUND

Gastrointestinal stromal tumor (GIST), a form of soft tissue sarcoma, is often detected incidentally or at an advanced stage. The tyrosine kinase inhibitor sunitinib malate (Sutent * ) is established as second-line treatment for the management of GIST after disease progression on, or intolerance to, first-line imatinib treatment. Several published reviews give guidance on management of side effects in patients with advanced renal cell carcinoma treated with sunitinib, but fewer publications cover side-effect management in patients with GIST.

SCOPE

Using published articles and abstracts, prescribing information, and personal experience in managing patients with GIST at a specialized center of excellence for cancer care, I review side-effect management recommendations for patients with GIST treated with sunitinib and provide an overview of GIST.

FINDINGS

Sunitinib has a well described side-effect profile: most side effects occurring in patients with GIST can be easily managed by standard medical intervention and/or dose modification.

CONCLUSION

Care of patients with GIST can be enhanced through communication, support, knowledge, and education, with the goal of providing effective therapy and optimal symptom control.

Exophytic gastrointestinal stromal tumor with cystic changes: A case report

Gastrointestinal stromal tumor (GIST) is the most common type of mesenchymal tumor in the gastrointestinal tract. A large tumor size often means a poor prognosis. This report presents a case of a large exophytic GIST with cyst change, for which the outcome of favourable prognosis was unexpected. A 78-year-old male presented with abdominal distension and a poor appetite, and was primarily diagnosed with a pancreatic mass. Abdominal ultrasonography, computed tomography and magnetic resonance imaging revealed a tumor in the body of the pancreas, which was closely attached to the gastric wall. Surgery was performed to excise the tumor. The tumor originated from the gastric cells and was ~17×15×16 cm in size. A diagnosis of GIST was confirmed by histomorphological and immunohistochemical findings. According to the postoperative findings, the tumor was classified to be in the high-risk group, for which the suggested treatment is imatinib. However, the patient was not treated with imatinib and, three years following surgery, the patient is alive with no evidence of tumor recurrence.

Role of Ki-67 as a prognostic factor in gastrointestinal stromal tumors

AIM: To investigate primarily the prognostic value of Ki-67, as well as other parameters, in gastrointestinal stromal tumors (GISTs).

METHODS: Ki-67, c-KIT, platelet-derived growth factor receptor-alpha (PDGFRα), smooth muscle actin (SMA), CD34, S100 were stained for immunohistochemistry which was performed on formalin-fixed, paraffin-embeded sections on representative block from each case. Proliferation index counted by Ki-67 antibody was calculated as a number of positive nuclear reaction over 100 cells. Immunoreactivity for c-KIT and PDGFRα was evaluated semiquantitatively (weak, intermediate, strong) and for c-KIT type of reactivity was analyzed (cytoplasmic, membrane and "dot-like" staining). Immunoreactivity for SMA, CD34 and S100 were was evaluated as positive or negative antigen expression. Pathologic parameters investigated in this study included tumor size, cell type (pure spindle, pured epitheloid mixed spindle and epitheloid), mitotic count, hemorrhage, necrosis, mucosal ulceration. Clinical data included age, gender, primary tumor location and spread of disease. χ² test and Student's t-test were used for comparisons of baseline characteristics. The Cox’s proportional hazard model was used for univariable and multivariable analyses. Survival rates were calculated by Kaplan-Meier method and statistical significance was determined by the log-rank test.

RESULTS: According to the stage of disease, there were 36 patients with localized disease, 29 patients with initially localized disease but with its recurrence in the period of follow up, and finally, 35 patients had metastatic disease from the very beginning of disease. Tumor originated most commonly in the stomach (41%), small intestine was the second most common location (36%). The mean size of primary tumors was 6.5 cm. The mean duration of follow-up was 60 mo. Multiple parameters were analyzed for their effect on overall survival, but no one reached statistical significance (P = 0.06). Analysis of time to progression/relapse in initially localized disease (univariate analysis), tumor size, mitotic count, Ki-67 and type of d-KIT distribution (cytoplasmic vs membrane/”dot-like”) showed statistically significant correlation. In multivariate analysis in the group of patients with localized disease, there were only 2 parameters that have impact on relapse, Ki-67 and SMA (P < 0.0001 and P < 0.034, respectively). Furthermore, Ki-67 was analyzed in localized disease vs localized with recurrence and metastatic disease. It was shown that there is a strict difference between these 2 groups of patients (median value was 2.5 for localized disease vs 10.0 for recurrent/metastatic disease, P < 0.0001). It was also shown that the cut-off value which is still statistically significant in terms of relapse on the level of 6%. The curves for survival on that cut-off level are significantly different (P < 0.04, Cox F).

CONCLUSION: Ki-67 presents a significant prognostic factor for GIST recurrence which could be of great importance in evaluating malignant potential of disease.

Updates on the management of gastrointestinal stromal tumors

Despite being the most common sarcoma of the gastrointestinal tract, gastrointestinal stromal tumor (GIST) has been widely recognized as a unique entity for just over a decade. The advent of tyrosine kinase inhibitors has revolutionized the diagnosis and treatment of GIST. Although surgery remains the only chance for cure, multimodal treatment that includes molecular therapy continues to develop. Optimal management of GIST requires careful radiographic, pathologic, medical, and surgical care, emphasizing the need for a multidisciplinary approach. This review highlights recent developments in the management of GIST.

A nuclear grading system is a strong predictor of survival in epitheloid diffuse malignant pleural mesothelioma

Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant pleural mesothelioma in which only staging is prognostic for survival. In this study of epithelioid diffuse malignant pleural mesothelioma, we investigate the prognostic utility of nuclear features. The slides of 232 epithelioid diffuse malignant pleural mesothelioma patients (14 stage I, 54 stage II, 130 stage III, and 34 stage IV) from a single institution were reviewed for the following seven nuclear features: nuclear atypia, nuclear/cytoplasmic ratio, chromatin pattern, intranuclear inclusions, prominence of nucleoli, mitotic count, and atypical mitoses. MIB-1 immunohistochemistry was performed using tissue microarray, and MIB-1 labeling index was recorded as the percentage of positive tumor cells. Median overall survival of all patients was 16 months and correlated with nuclear atypia (P<0.001), chromatin pattern (P=0.031), prominence of nucleoli (P<0.001), mitotic count (P<0.001), and atypical mitoses (P<0.001) by univariate analysis. Multivariate analysis revealed nuclear atypia (P=0.012) and mitotic count (P<0.001) as independent prognostic factors, and these two factors were utilized to create a three-tier nuclear grade score. The resulting nuclear grade stratified patients into three distinct prognostic groups: grade I (n=107, median overall survival=28 months), grade II (n=91, 14 months), and grade III (n=34, 5 months). Not only was nuclear grade an independent predictor of overall survival (P<0.001), but it was also a stronger discriminator of survival than all currently available factors. Furthermore, nuclear grade was associated with time to recurrence (P=0.004) in patients who underwent complete surgical resection (n=159). MIB-1 labeling index correlated with mitotic count (P<0.001) and nuclear atypia (P=0.037) and stratified overall survival (P<0.001) and time to recurrence (P=0.048), confirming the prognostic value of the nuclear grade. Nuclear grading in epithelioid mesothelioma provides a simple, practical, and cost-effective prognostic tool that better stratifies clinical outcome and time to recurrence than currently available clinicopathologic factors.

Gastrointestinal stromal tumor: advances in diagnosis and management

CONTEXT

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract and should be differentiated from other mesenchymal tumors. They harbor specific activating mutations in the KIT or platelet-derived growth factor receptor α ( PDGFRA ) receptor tyrosine kinases, which makes them responsive to pharmacologic inhibitors, such as imatinib mesylate and sunitinib malate.

OBJECTIVES

To provide a comprehensive review of the pathogenesis of GIST and the underlying principles of targeted therapy, to review the salient histologic and immunohistochemical features that facilitate the distinction of GIST from other mesenchymal neoplasms of the gastrointestinal tract, and to present the prognostic parameters for risk stratification that guide clinical management.

DATA SOURCES

Review of the English literature through PubMed as well as personal experience. Photographs were taken from cases encountered at the Cleveland Clinic.

CONCLUSIONS

The discovery of the KIT -GIST connection has not only improved the diagnostic accuracy of GISTs but also provided us with a better understanding of the histogenesis and molecular pathogenesis of these neoplasms.

The effect of neoadjuvant Imatinib therapy on outcome and survival after rectal gastrointestinal stromal tumour

AIM

The study aimed to characterize the pathological and clinical response of rectal gastrointestinal stromal tumours (GISTs) to neoadjuvant Imatinib.

METHOD

The medical records of patients with rectal GISTs who were diagnosed and treated in five medical centres in Israel between January 2002 and January 2009 were retrospectively examined. Twelve patients who fulfilled the inclusion criteria of nonmetastatic rectal GIST for which preoperative neoadjuvant treatment with Imatinib was considered were suitable for enrollment.

RESULTS

Of the 12 patients, nine received neoadjuvant treatment with Imatinib. The three patients who had immediate surgery were excluded. There were five men and four women with a median age of 63 years and a median follow up of 32 months. All tumours were located in the lower two-thirds of the rectum. One patient had a complete clinical response, six had a partial response and two had stable disease. Seven patients subsequently underwent surgery; six had an R0 resection and one had an R1 resection. Three patients had recurrence. There was no disease-related mortality. The reduction in both tumour size and mitotic activity during preoperative Imatinib therapy was significant.

CONCLUSION

Preoperative Imatinib therapy can shrink large rectal GISTs, improving the chances of successful radical surgery and decreasing the risk of considerable morbidity.

Gastrointestinal stromal tumours: an update

Purpose. To study the evolution of concepts concerning gastrointestinal stromal tumours (GISTs) over 30 years.Discussion. GISTs have been, for more than 30 years, the subject of considerable controversy regarding their line of differentiation as well as the prediction of their behaviour. Furthermore, once they spread within the peritoneal cavity, they are extremely hard to control. The recent findings of c-Kit mutations and the immunohistochemical detection of the product of this gene, KIT or CD117, in the mainly non-myogenic subset of this family of tumours, has led to a reappraisal of this group of lesions, which, with some exceptions, is now thought to be derived from the interstitial cells of Cajal, and this has facilitated a clearer definition of their pathological spectrum. In this article, we review chronologically the evolution of the concept of GIST with the gradual application of electron microscopy, immunohistochemistry, DNA ploidy analysis. We discuss the impact of these techniques on the pathological assessment and clinical management of GISTs.

Gastrointestinal stromal tumors (GISTs): an updated experience

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are relatively common mesenchymal tumors of the digestive tract characterized by c-KIT mutations. This is a comprehensive review of the current data of the literature on the various aspects of the diagnosis and treatment of these tumors.

METHODS

The stomach is the most commonly involved site for these tumors in the digestive tract. Computed tomography and endoscopy can usually establish the diagnosis. The study of certain specific immunohistochemical markers may contribute to better characterization of these tumors.

RESULTS

Surgical resection of GISTs has been the most effective therapy. In addition, targeted therapy with tyrosine kinase inhibitors may reduce the development of recurrence or decrease the disease progression in patients with metastatic disease.

CONCLUSIONS

The introduction of tyrosine kinase inhibitors has resulted in significant improvement in the overall prognosis of these patients. Furthermore, preoperative imatinib can decrease tumor volume and is associated with complete surgical resection in locally advanced primary GISTs.

Gastrointestinal stromal tumors–a review

Gastrointestinal stromal tumors (GISTs) may be defined as intraabdominal nonepithelial (mesenchymal) tumors that express the KIT protein or have an activating mutation in a class III receptor tyrosine kinase gene (KIT or PDGFRA). GISTs are diagnosed at a frequency of about 15 new cases annually per million, though small indolent GISTs are likely to occur more frequently in the general population. The clinical behavior is variable, and assessment of the malignancy potential is usually based mainly on the size and the proliferation characteristics of the tumor. The overwhelming majority of GISTs express the KIT protein, the transmembrane receptor tyrosine kinase for the stem cell factor. The majority of GISTs harbor a mutation in the KIT proto-oncogene that translates into constitutively activated KIT protein kinase, and a minority have mutated PDGFRA gene resulting in activated platelet-derived growth factor alpha receptor tyrosine kinase. Most GISTs respond to imatinib mesylate, which selectively inhibits both KIT and PDGFRA, and is now considered as the standard systemic therapy for advanced GIST. In contrast, responses to conventional chemotherapy are infrequent (generally less than 10%), but combination therapies with imatinib have not been explored. Research on adjuvant imatinib and novel targeted therapies is ongoing.

Management of resectable gastrointestinal stromal tumor

Gastrointestinal stromal tumor (GIST) is a rare neoplasm that recently has become an intense focus of scientific investigation, as it serves as a model for the molecular therapy for cancer. Although surgery remains the principle treatment of primary localized GIST, imatinib mesylate, a selective inhibitor of KIT protein, achieves dramatic responses in metastatic GIST. Multimodality therapy integrating surgery and molecular therapy has shown promise. This article summarizes the epidemiology, clinicopathologic features, natural history, and clinical management of GIST.

Gastrointestinal stromal tumor: a clinical overview

Gastrointestinal stromal tumor (GIST) is a disease that was poorly understood historically. In the last decade, it has undergone a major transformation, sparked by the landmark discovery of the central role of activating KIT mutations in its pathogenesis and recognition of KIT protein expression (CD 117) as a reliable diagnostic marker of disease. The introduction and subsequent US Food and Drug administration approval of imatinib mesylate in the treatment of metastatic or unresectable GIST in February 1, 2002 has thrust this hitherto little known disease into the center stage of oncology, and GIST has served as a model for rationally designed drug trials in the field of cancer therapeutics since.

Multidisciplinary treatment of gastrointestinal stromal tumors

Gastrointestinal stromal tumor (GIST) has been recognized as a unique tumor only in the last decade. Although rare as a clinical entity, there is much interest in the pathology and treatment because the KIT protooncogene mutation common to most GISTs can be inhibited by imatinib mesylate. Diagnosing and treating GIST requires a multidisciplinary approach, given the combination of pathologic and radiographic evaluation, surgical treatment, and oncologic care required to successfully treat patients with GIST.

Clinicopathological characteristics of gastrointestinal mesenchymal tumors and diagnostic value of endoscopic ultrasonography

BACKGROUND AND AIM

Gastrointestinal mesenchymal tumors (GIMTs) are tumors which arise from mesenchymal cells other than lymphocytes or epithelial cells and include gastrointestinal stromal tumors (GISTs), smooth muscle tumors, neurogenic tumors, fibroblast tumors, and liparomphalus. Here, we studied the clinicopathologic characteristics of GIMTs and determined the diagnostic value of endoscopic ultrasonography (EUS) in GIMTs.

METHODS

The morphological characteristics of 415 GIMT cases were observed using light microscopy. The expression of CD117, CD34, smooth muscle actin (SMA), S-100, and Ki-67 were detected using immunohistochemistry. EUS results were retrospectively analyzed in 76 cases.

RESULTS

Among the 415 GIMT cases, there were 229 GIST cases, 178 smooth muscle tumor cases, and eight neurogenic tumor cases. Diffuse strong expression of CD117 was observed in 202 (88.2%) GISTs and strong expression of CD34 was observed in 135 (59.0%) GISTs. SMA and S-100 expression was detected in smooth muscle tumors (leiomyomas/leiomyosarcoma) and neurogenic tumors, respectively. Of the 12 cases with GISTs, nine cases with positive ki-67 expression and accompanied with more mitosis were pathologically diagnosed as malignant GISTs. Most of the borderline and malignant tumors were found in male patients. EUS was 98.7% accurate in determining GIMT locations, 82.9% accurate in diagnosing GIMTs, and 80.3% accurate in differentiating benign from malignant tumors.

CONCLUSIONS

GISTs, rather than leiomyomas, are the most common GIMTs. Immunohistochemical markers, such as CD117, CD34, SMA, and S-100, can differentiate GISTs from smooth muscle and neurogenic tumors. The expression of Ki-67 in patients with significant karyokinesis supports a malignant tumor diagnosis. EUS is an accurate method for detecting GIMTs and differentiating between benign and malignant tumors. Use of endoscopic ultrasound-guided fine-needle aspiration biopsies may enable clinicians to make more accurate diagnoses than currently used methods.

P53 expression is significantly correlated with high risk of malignancy and epithelioid differentiation in GISTs. An immunohistochemical study of 104 cases

BACKGROUND

Molecular analyses of the c-kit and PDGFRalpha genes have contributed greatly to our understanding of the development of gastrointestinal stromal tumors (GISTs), but little is known about their malignant potential. The aim of our study was to evaluate cell cycle regulators as potential prognostic markers in GISTs.

METHODS

We investigated 104 KIT positive GISTs from various tumor sites in immunoassays on CD34, Ki67 and particularly on P53, BCL-2 and Cyclin D1. The results were compared with tumor size, mitotic rate, proliferative activity, histological subtype, nuclear atypia and risk assessment according to Fletcher and Miettinen. Occurrence of metastases and survival were also taken into account.

RESULTS

The expression of P53 was significantly correlated with high risk criteria towards malignancy and epithelioid differentiation in GISTs. Likewise P53 label correlated significantly with the established prognostic indicators: tumor size, mitotic rate, nuclear atypia and proliferative activity. Regarding the site of tumor presentation, P53 was not a decisive factor. BCL-2 and Cyclin D1 expression was not related to any of the prognostic indicators.

CONCLUSION

The present data identified P53 being a recommendable marker for predicting the risk of malignancy in GISTs. In addition, we found P53 significantly correlated with epithelioid tumor differentiation, independent of tumor site. BCL-2 and Cyclin D1, however, did not prove to be deciding markers for diagnosis and prognosis.

Gastrointestinal stromal tumors and leiomyosarcomas

Only recently has gastrointestinal stromal tumor (GIST) been recognized as the most frequent GI mesenchymal neoplasm. Prior to the use of KIT staining, most GI stromal tumors were identified as leiomyosarcoma (LMS). For primary GIST, surgery remains the principal treatment and adjuvant imatinib may improve outcomes. Multimodality therapy may also be effective in patients with metastatic GIST. In this review, we summarize the epidemiology, clinicopathologic features, natural history, and clinical management of LMS and GIST.

Gastrointestinal stromal tumour of the rectum: Report of a case and review of literature

Gastrointestinal stromal tumour (GIST) is a rare tumour of the gastrointestinal tract which does not generally originate in the rectum. The authors describe a case of a 70-year-old man who underwent an anterior resection of the rectum for a low-risk GIST. The patient was not given adjuvant chemotherapy with imatinib and is still disease-free 30 mo after surgery. The authors conclude that although rectal GIST is extremely uncommon, it should be included in differential diagnosis when a tumour in the rectum is detected. Biopsy of the tumour is essential, since this makes it possible to reach a sure preoperative diagnosis based on the immunohistological features of the CD117 and CD34. Although complete surgical resection with negative tumour margins is the principal curative procedure for primary and non-metastatic tumours, further studies are still needed for the determination of the most effective treatment strategy for patients with rectal GIST.

Outcome after surgical treatment of gastrointestinal stromal tumors

OBJECTIVES

The objectives were to determine among gastrointestinal mesenchymal tumors treated surgically in our unit which were gastrointestinal stromal tumors (GISTs) and to describe their characteristic features and prognostic factors.

METHODS

A second histological and immunohistochemical reading was performed for 56 gastrointestinal mesenchymal tumors, treated surgically in the Reims University Hospital between 1990 and 2005 in order to determine which ones were GISTs. A statistical descriptive and analytical analysis of the demographic, pathological, therapeutic and prognostic factors was performed.

RESULTS

Eighty-seven percent of the tumors were GISTs. The 5-year specific survival rate was 66.8%. The factors of good prognosis were small tumor size, low mitotic count, complete primary tumor resection without tumor effraction, age less than 60 years, absence of mucosal necrosis, ulceration, and invasion. Type of surgical resection had no impact in terms of survival.

CONCLUSION

GISTs are the most common mesenchymal tumors of the digestive tract. Even thought treatment with imatinib is currently available, surgery (preferably total resection without effraction) is the mainstay treatment for GISTs.

Prediction of aggressiveness of gastrointestinal stromal tumours based on immunostaining with bcl-2, Ki-67 and p53

OBJECTIVE

While the use of fine needle aspiration (FNA) in the diagnosis of gastrointestinal stromal tumours (GISTs) is well-established, it can be difficult to predict the prognosis of GIST based on morphology alone. The objective of the current study was to determine if expression of bcl-2, Ki-67 and p53 correlated with the outcome of GISTs based on cytological material.

METHODS

Cell-blocks from 14 GISTs diagnosed by FNA were retrieved. Immunostaining was performed with antibodies against bcl-2, Ki-67 and p53. All cytological diagnoses were confirmed by positive immunostaining with c-kit and/or subsequent histological evaluation. Positivity for bcl-2, Ki-67 and p53 was defined as the presence of > or =10% cytoplasmic staining, > or =5% nuclear staining and > or =5% nuclear staining respectively.

RESULTS

The 14 patients consisted of seven males and seven females with a mean age of 58 years. The average follow-up interval was 46 months. Six had a benign course and eight developed recurrences/metastases. Thirteen (93%) cases showed positive staining for bcl-2. Positive Ki-67 and p53 staining was noted in one (7%) and seven (50%) cases respectively. The difference in staining for p53 between aggressive and non-aggressive GISTs was statistically significant. No statistically significant difference was noted for bcl-2 staining or Ki-67 labelling index between the two groups.

CONCLUSIONS

According to our observations, p53 immunostaining may be useful in predicting the outcome of GIST diagnosed by FNA; Ki-67 and bcl-2 are not useful as prognostic markers for GIST in FNA specimens.

Gastrointestinal malignancies in HIV-infected or immunosuppressed patients: pathologic features and review of the literature

The gastrointestinal (GI) tract is a common internal organ to be involved by human immunodeficiency virus (HIV)-related malignancies. It is the second most common site for Kaposi sarcoma after skin, and the commonest visceral site, for Kaposi sarcoma in AIDS patients. GI lymphomas have been documented in approximately 25% of AIDS patients with systemic lymphomas. Moreover, GI involvement of AIDS-lymphoma has been associated with poor prognosis and short survival. Several other malignancies that occur in the GI tract are also closely related to HIV-infected or immunosuppressed individuals; these include posttransplant lymphoproliferative disorder, Epstein-Barr virus-associated smooth muscle tumors, anal precancerous lesions, and squamous cell carcinoma. As a result of active antiretroviral therapy, patients infected with HIV are living longer and are consequently at increased risk for development of cancer. Therefore, it is possible that the number of AIDS-associated malignancies will rise and the pattern of tumors may change in the future. In this paper, the clinicopathologic features of GI malignancies associated with AIDS patients are reviewed and the differential diagnosis with other mimic lesions is discussed.

Protein S100 as prognostic marker for gastrointestinal stromal tumors: a clinicopathological risk factor analysis

Gastrointestinal stromal tumors (GISTs) are a heterogenous group of mesenchymal neoplasms ranging from semibenign tumors to highly aggressive neoplasms. Predicting their clinical behavior is challenging and criteria delineating benign from malignant cases are controversially discussed. The aims of the present study were to define the clinicopathological features of 35 GISTs and to determine whether any specific parameters were associated with the patient's outcome. In the present series, protein S100 (S100) expression was found in 13/35 (37%) patients with a varying staining intensity ranging between strong and moderate. The multivariate statistical analysis in the S100-positive group revealed a significantly poorer survival (p = .0058) and a tendency for higher recurrence (p = .052) compared to the negative GIST patients. Furthermore, the statistical analysis disclosed a correlation between the expression of CD117, CD34, desmin, and alpha-smooth muscle actin and survival or recurrence (p > .05). Positive immunoreactivity was seen for CD117 in 25 (71%) patients and for CD34 in 19 (54%) patients. In addition we confirmed the previously reported impact of initial tumor size on survival and recurrence rate (p = .034 and p = .039). The series was also analyzed according to established prognostic factors (tumor size and mitotic activity), which indicated that 77% of S100-positive cases were at high risk for malignant tumor behavior, 15% at intermediate risk, and 8% at low risk. Based on these findings, we suggest that protein S100 represents an additional prognostic factor to better define the malignant potential of GISTs and stratify the risk for each patient.

Tumor size is a major determinant of recurrence in patients with resectable gastrointestinal stromal tumor

BACKGROUND

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumor of the gastrointestinal tract. Surgery remains the mainstay of curative treatment. Recurrence after surgery was frequent and was associated with poor prognosis. In this study, we tried to identify predictors of recurrence in resectable GISTs.

METHODS

Between January 1995 and December 2005, 100 patients undergoing surgical resection for GISTs in 2 hospitals were studied.

RESULTS

There were 67 gastric and 33 intestinal GISTs. Recurrence was noted in 11 patients (median follow-up of 43 months). Overall 5-year survival was 84%. Multivariate analysis demonstrated that tumor size > or = 10 cm was associated with higher recurrence rates (P = .032) and was the only independent poor prognostic factor for survival (P = .020).

CONCLUSIONS

We concluded that tumor size > or = 10 cm carried both a higher risk of recurrence and worse survival in resectable GISTs and could be considered an indicator for adjuvant therapy.

Significance of CD44 expression in gastrointestinal stromal tumors in relation to disease progression and survival

BACKGROUND

CD44 is a transmembrane glycoprotein belonging to the cell-adhesion molecule family. It has been identified as being involved in tumor progression and metastasis, and its expression has been found to be of prognostic significance in several human malignancies. The aim of this study was to assess CD44 expression in gastrointestinal stromal tumors (GISTs), the most common mesenchymal tumor of the gastrointestinal tract.

METHODS

Between January 1995 and March 2006, 92 patients undergoing surgical resection for GIST in National Cheng Kung University Hospital were evaluated. To study the significance of CD44 expression, immunohistochemical staining of CD44 in tumor specimens was performed, and the clinicopathological information of patients was reviewed.

RESULTS

Fifty-nine of 81 patients (73%) showed positive CD44 expression. Loss of CD44 expression was associated with disease progression (p = 0.019). Kaplan-Meier analysis revealed better progression-free survival among patients with strong CD44 expression (++ and +++) (p = 0.034), absence of disease progression (p < 0.001), and lower risk, according to National Institutes of Health (NIH) Consensus Criteria for GIST risk stratification (p = 0.003). Multivariate analysis demonstrated that high-risk status was the only independent risk factor for disease progression and the only independent predictor for a poor progression-free survival (p = 0.023 and 0.045, respectively).

CONCLUSIONS

It is demonstrated that high-risk status by NIH criteria is significantly associated with disease progression and poor progression-free survival in GIST.

Gastric GIST: a single institutional retrospective experience with surgical treatment for primary disease

AIMS

Because gastric GISTs show variable clinical behavior, we reviewed our experience with primary gastric GISTs after surgical treatment and imatinib mesylate treatment for advanced disease.

METHODS

Between December 1995 and December 2005, 111 patients who underwent surgical treatment for primary gastric GISTs were enrolled in this study. Patients were grouped according to the risk assessment classification, and clinicopathological features, tumor recurrence and patient survival were assessed.

RESULTS

One patient was included in the very low risk group, 35 in the low risk group, 31 in the intermediate risk group and 44 in the high-risk group. All patients with very low, low and intermediate risk GISTs and 70% of patients with high risk GISTs underwent R0 resection. While there was no recurrence or metastasis in patients with very low, low and intermediate risk GISTs, 23% of those with high risk GISTs showed a distant metastasis at diagnosis and 35% of these patients had a recurrence after R0 resection. The overall 5-year survival rate of the high risk patients was 77.1%. Nineteen patients received imatinib mesylate therapy due to an incomplete resection or recurrence; 7 with no measurable lesion at the CT scan by a local tumor control showed no tumor progression after imatinib mesylate therapy, however, 12 patients with measurable lesions showed variable clinical courses after treatment. The overall 5-year survival rate of 19 patients with imatinib mesylate treatment was 80.0%.

CONCLUSIONS

The clinical outcome of the very low, low and intermediate risk gastric GISTs was excellent, while high risk gastric GISTs had a high rate of recurrence and therefore a less favorable outcome. A complete resection is the most important treatment for cure; however imatinib mesylate treatment may improve the clinical outcome of the patients with metastatic or recurrent gastric GISTs.

Primary oral KIT-positive tumour consistent with gastrointestinal stromal tumour

Gastrointestinal stromal tumours are characteristically positive for KIT (reflective of the c-KIT gene). A case is reported of an apparent rapidly growing gastrointestinal stromal tumour, which arose in the floor of the mouth and metastasized to the left neck without evidence of disease elsewhere.

Correlation of enhanced cell turnover with prognosis of gastrointestinal stromal tumors of the stomach: Relevance of cellularity and p27Kip1

The aim of the present study was to determine whether expression of molecules associated with cell cycle regulation and apoptosis might reflect tumor grade and patients' prognosis of gastrointestinal stromal tumor (GIST). Forty-nine cases of gastric GIST were divided into three grades; low, intermediate, and high risk. Ki-67, cyclin A, cyclin D1, cyclin E, p16(Ink4), p21(Waf1), p27(Kip1), cyclin-dependent kinase (cdk)2, cdk4 and single-strand DNA (ssDNA) were immunohistochemically stained and assessed. Ki-67, ssDNA, cyclin A and cdk2 had higher labeling indices (LI) in high-risk than in low-risk cases. Cyclin E expression was greater in the intermediate- than in the low-risk grade. On Kaplan-Meier analysis, tumor size, necrosis, cellularity, Ki-67, ssDNA, and cyclin A LI were significantly correlated with disease-free survival. Necrosis, cellularity, and Ki-67 LI were significant as prognostic factors on univariate, and Ki-67 LI on multivariate Cox hazard tests. Within the high-risk grade, high cellularity and low p27(Kip1) subgroups had the worst prognosis. The histological grade is related to cell turnover, assessed in terms of Ki-67, ssDNA, cyclin A, cyclin E, and cdk2 levels. Ki-67, ssDNA, and cyclin A are useful for prediction of prognosis, with cellularity and p27(Kip1) expression as further prognostic factors in high-risk cases.

Gastrointestinal stromal tumors: review on morphology, molecular pathology, prognosis, and differential diagnosis

CONTEXT

Gastrointestinal stromal tumors (GISTs) are specific, generally Kit (CD117)-positive, mesenchymal tumors of the gastrointestinal tract encompassing a majority of tumors previously considered gastrointestinal smooth muscle tumors. They are believed to originate from interstitial cells of Cajal or related stem cells.

OBJECTIVE

To review current clinicopathologically relevant information on GIST.

DATA SOURCES

Literature in Medline and authors' own experience.

CONCLUSIONS

GISTs usually occur in older adults (median age 55-60 years) and rarely in children in the second decade (<1%) throughout the gastrointestinal tract: 60% in stomach, 35% in small intestine, and less than 5% in rectum, esophagus, omentum, and mesentery; most GISTs in the latter 2 sites are metastatic. Five percent of GISTs occur in patients with neurofibromatosis type 1 syndrome (multiple small intestinal tumors) and in Carney triad (gastric epithelioid GISTs in young females). Familial GISTs occur in patients with inheritable germline Kit or platelet-derived growth factor receptor alpha (PDGFRA) mutations. Histologically GISTs vary from spindle cell tumors to epithelioid and pleomorphic tumors. Most GISTs (95%) express Kit (CD117), CD34 (70%), and heavy caldesmon (80%), whereas 25% are positive for smooth muscle actin and less than 5% for desmin. Tumor size and mitotic activity are best predictive prognostic features; small intestinal tumors behave more aggressively than gastric tumors with similar parameters. Mutually exclusive gain-of-function Kit or PDGFRA mutations occur in a majority of GISTs representing in-frame deletions, point mutations, duplications and insertions. Mutations in Kit juxtamembrane domain (exon 11) are the most common in GISTs of all sites, whereas rare Kit extracellular domain (exon 9) Ala502-Tyr503 duplication is specific for intestinal GISTs. Mutations in PDGFRA have been identified in juxtamembrane (exon 12) and tyrosine kinase domains (exons 14 and 18), nearly exclusively in gastric GISTs, mostly in epithelioid variants. Some Kit and PDGFRA mutations have a prognostic value. Kit/PDGFRA tyrosine kinase inhibitor imatinib has been successfully used in the treatment of metastatic GISTs for more than 5 years. However, primary and acquired secondary resistance linked to certain types of Kit and PDGFRA mutations is limiting long-term success necessitating the use of alternative treatments.

Surgical treatment and prognostic analysis for gastrointestinal stromal tumors (GISTs) of the small intestine: before the era of imatinib mesylate

BACKGROUND

Gastrointestinal stromal tumors (GISTs), the most common type of mesenchymal tumors of the gastrointestinal (GI) tract, demonstrate positive kit staining. We report our surgical experience with 100 small intestine GIST patients and identify predictors for long-term disease-free survival (DFS) and overall survival (OS) to clarify the difference between high- and low-risk patients.

METHODS

The clinicopathologic and follow-up records of 100 small intestine GIST patients who were treated at Chung Gung Memorial Hospital between 1983 and 2002 were retrospectively reviewed. Clinical and pathological factors were assessed for long-term DFS and OS by using a univariate log-rank test and a multivariate Cox proportional hazard model.

RESULTS

The patients included 52 men and 48 women. Their ages ranged from 27 to 82 years. Among the 85 patients who underwent curative resection, 44 (51.8%) developed disease recurrence (liver metastasis was the most common form of recurrence). The follow-up period ranged from 5 to 202 months (median: 33.2 months). The 1-, 3-, and 5-year DFS and OS rates were 85.2%, 53.8%, and 43.7%, and 91.5%, 66.6%, and 50.5%, respectively. Using multivariate analysis, it was found that high tumor cellularity, mitotic count >5/50 high-power field, and a Ki-67 index > or =10% were three independent factors that were inversely associated with DFS. However, absence of tumor perforation, mitotic count < 5/50 high power field, and tumor with low cellularity were predictors of long-term favorable OS.

CONCLUSION

Tumors with low cellularity, low mitotic count, and low Ki-67 index, which indicate low risk, predict a more favorable DFS for small intestine GIST patients undergoing curative resection. Absence of tumor perforation with low mitotic count and low cellularity, which indicates low risk, can predict long-term OS for small intestine GIST patients who have undergone curative resection.

Immunohistochemical expression of p16INK4A, Ki-67, and Mcm2 proteins in gastrointestinal stromal tumors: prognostic implications and correlations with risk stratification of NIH consensus criteria

BACKGROUND

Inactivation of p16(INK4A) promotes G1/S progression of cell cycle. Minichromosome maintenance protein-2 (Mcm2), a novel cell proliferation marker, is known to better correlate with clinical outcomes than Ki-67 in many carcinomas. Since gastrointestinal stromal tumors (GISTs) sometimes remains challenging in prognostication, we analyzed the utility of these three markers in GISTs.

METHODS

Immunohistochemistry was performed in tissue microarrays of 277 primary GISTs and correlated with NIH consensus criteria and clinical outcomes.

RESULTS

The increment of NIH risk levels significantly correlated with increasing labeling indices (LI) of both Ki-67 (P <.001) and Mcm2 (P <.001) and loss of p16(INK4A) expression (P <.035). However, the latter aberration did occur in 23% of very low/low-risk GISTs. The relationship between Mcm2 and Ki-67 LIs could be modeled as linear (P <.001, r = 0.697), while Mcm2 LI was considerably higher (P <.001) with a stepwise escalation related to risk levels. Ki-67 LI >5% (P <.0001) and Mcm2 LI >10% (P <.0001) were strongly predictive of inferior disease-specific survival (DSS), while aberrant loss of p16(INK4A) only reached a trend (P = .0954). In multivariate analyses, independent adverse factors of DSS were high-risk category (RR = 16.93, P <.0001), metastatic disease (RR = 4.12, P = .0015), Ki-67 LI >5% (RR = 3.55, P = .001), and presence of epithelioid histology (RR = 2.17, P = .0308).

CONCLUSIONS

Prognostic efficacy of NIH consensus criteria is substantiated. P16(INK4A) deregulation can occur early in GIST tumorigenesis and marginally correlates with patient survival. Despite Ki-67 LI being an independent prognosticator, simultaneous detection of Mcm2 is recommended as a prognostic adjunct of GISTs, given its better sensitivity and stepwise escalation with increasing risk levels.

Gastrointestinal stromal tumours: an update

Recently, there has been intense interest in the study of gastrointestinal stromal tumour (GIST); one might call it a virtual GIST revolution. This is due largely to the realization that most GISTs express KIT and harbour activating c-KIT (KIT) or platelet-derived growth factor receptor-alpha (PDGFRA) receptor tyrosine kinase mutations that can be targeted by small molecule pharmacological inhibitors. Pathologists have benefited greatly from this revolution, mainly in the form of an improved ability to classify GISTs and, even more recently, in understanding the molecular underpinnings that underlie many fascinating clinical and pathological correlations. It is the purpose of this review to summarize recent developments in GIST classification and the molecular pathogenesis of GIST.

Multiple gastrointestinal stromal tumors and synchronous ileal carcinoids

BACKGROUND

A 74-year-old African-American male presented with a 3-day history of hematemesis and melena. The patient reported no abdominal pain, constitutional symptoms, bright red blood per rectum, constipation, or diarrhea. His physical examination and medical history were unremarkable except for benign prostatic hypertrophy. An esophagogastroduodenoscopy showed a 3 x 2 x 2 cm smooth round mass in the cardia, 2 cm distal to the gastroesophageal junction. Biopsy of the mass revealed an ulcerated tumor composed of spindle cells. Immunohistochemistry showed positive staining for a number of biochemical markers, including KIT, Ki-67 and smooth muscle actin, but was negative for the markers S100 and desmin. A gastric-wedge resection revealed an ulcerated 4.5 cm mass in the stomach, and exploration of the abdomen revealed two ileal carcinoid tumors, jejunal diverticula and reactive mesenteric lymphadenopathy.

INVESTIGATIONS

Esophagogastroduodenoscopy, biopsy, CT scan, immunohistochemistry, DNA microarray analysis and quantitative reverse transcriptase-PCR.

DIAGNOSIS

Multiple gastrointestinal stromal tumors occurring concomitantly with ileal carcinoids.

MANAGEMENT

Gastric-wedge resection and segmental resection.

Patterns of gene amplification in gastrointestinal stromal tumors (GIST)

Gastrointestinal stromal tumors (GIST) are the most common primary mesenchymal tumors of the gastrointestinal tract (GIT). They represent a wide clinico-pathological spectrum of tumors. No single histological or clinical parameter can predict the prognosis while the response to therapy is related to the type of KIT or PDGFRA mutation. Cytogenetic and CGH studies have identified frequent gross chromosomal aberrations but the target genes of these changes are unknown. To determine whether known oncogenes take part in genomic rearrangements and to investigate the potential clinical significance of their amplifications, nine known oncogenes (CMYC, MDM2, GLI1, CDK4, HER2, EGFR1, CCND1, FGF3, EMS) were analyzed by fluorescent in situ hybridization (FISH) on a tissue microarray (TMA) containing 94 primary GIST. Clinical follow-up information was available for 57 of these patients. Amplification was found for CMYC in three of 90 (3.3%), for MDM2 in five of 94 (5.3%), for EGFR1 in five of 94 (5.3%), and for CCND1 in seven of 79 (8.9%) evaluable cases. No amplifications were seen for HER2, GLI1, CDK4, FGF3, and EMS. Amplifications of MDM2 and CCND1 were associated with clinical and histological malignancy. In conclusion, our data show that gene amplification does occur in a subset of GIST. Identification of MDM2/CCND1 amplification may represent another molecular feature that could help in the evaluation of the behavior of GISTs.

Gastrointestinal stromal tumors: the incidence, prevalence, clinical course, and prognostication in the preimatinib mesylate era--a population-based study in western Sweden

BACKGROUND

Recent breakthroughs regarding gastrointestinal stromal tumors (GIST) and their pathogenesis have redefined diagnostic criteria and have led to the development of molecularly targeted drug therapy. New treatment options mandate more accurate information regarding the incidence, prevalence, clinical behavior, and prognostic factors of GIST.

METHODS

All patients (n=1460) who potentially had GIST diagnosed from 1983 to 2000 in western Sweden (population, 1.3-1.6 million) were reviewed, and 288 patients with primary GIST were identified. The incidence and prevalence of GIST were determined, and predictive prognostic factors, including current risk-group stratifications, were analyzed statistically.

RESULTS

Ninety percent of GISTs were detected clinically due to symptoms (69%) or were incidental findings at surgery (21%); the remaining 10% of GISTs were found at autopsy. Forty-four percent of symptomatic, clinically detected GISTs were categorized as high risk (29%) or overtly malignant (15%), with tumor-related deaths occurring in 63% of patients and 83% of patients, respectively (estimated median survival, of 40 months and 16 months, respectively). Tumor-related deaths occurred in only 2 of 170 of patients (1.2%) with very-low-risk, low-risk, or intermediate-risk tumors. The annual incidence of GIST was 14.5 per million. The prevalence of all GIST risk groups was 129 per million (31 per million for the high-risk group and the overtly malignant group).

CONCLUSIONS

GIST has been under recognized: Its incidence, prevalence, and clinical aggressiveness also have been underestimated. Currently existing risk-group stratification systems based on tumor size and mitotic rate delineate GIST patients who have a poor prognosis. Prognostication in patients with GIST can be refined using a proposed risk score based solely on tumor size and proliferative index.

Revision of gastrointestinal mesenchymal tumours with CD117

BACKGROUND

Tyrosinekinase inhibitors improve the treatment of gastrointestinal stromal tumours (GISTs) and their diagnosis has been facilitated by recently developed immunohistochemical markers. It is hypothesised that in the past, the true incidence of GISTs has been underestimated.

AIMS

To study the clinicopathological features of previously resected mesenchymal tumours of the gastrointestinal tract and determine the accuracy of previous diagnostic results.

PATIENTS AND METHODS

Patients with mesenchymal tumours of the gastrointestinal tract operated on between 1987 and 2002 were identified using medical and pathologic files. Immunohistochemical staining for CD117, CD34, desmin and S100 was performed, and diagnosis reviewed.

RESULTS

Thirty-six mesenchymal tumours were reanalysed. Before revision, diagnosis of GIST was correctly made in only six cases. Supportive use of immunohistochemical markers for accurate diagnosis of the remaining 30 previously undefined mesenchymal tumours yielded 17 additional GISTs. Therefore, 23 of 36 (63%) gastrointestinal mesenchymal tumours were shown to be GISTs.

CONCLUSIONS

The true incidence of GISTs has been underestimated. There is merit in reviewing the clinical diagnoses of all mesenchymal tumours of the gastrointestinal tract with modern immunohistochemical markers. This may enhance clinical decision making.