Gastrointestinal stromal tumors: clinicopathological study of Chinese cases

Evaluation of the gastrointestinal stromal tumors for clinical features, histopathological findings and prognostic criteria: A case-control study

OBJECTIVE:

In this study, we reviewed GISTs with all morphological and immunohistochemical findings and assessed the prognostic parameters of these tumors.

METHODS:

Files of 40 cases with GIST operated between 2002 and 2008 were retrospectively examined in this study. Patients were grouped as patients with and without recurrence within postop 1 year. The patients were grouped based on their localization, gender and age. The cases were stratified as the risk grades based on risk categorization table developed by Fletcher et al. according to the tumor diameter and number of mitoses. The cases were immunohistochemically investigated for CD117, CD34, S100, and Ki-67.

RESULTS:

Male/female ratio was 25/15. The mean age was 61.55. Mean tumor diameters were statistically significantly higher in the recurrence (+) group than in the recurrence (-) group (p=0.048). The mean number of mitoses was statistically significantly higher in the recurrence (+) group than in the recurrence (-) group (p=0.038). No statistically significant difference was found in histological distribution of the recurrence (-) and recurrence (+) groups (p=0.8795). No statistically significant difference was found in CD34, S100, and Ki-67 distribution of the recurrence (-) and recurrence (+) groups (p=0.862, p=0.609, and p=0.023, respectively). All patients in the recurrence (+) group were in the high-risk group.

CONCLUSION:

GISTs are studied in a wide range from benign, incidental tumors to malignant tumors with the risk for recurrence and metastasis concerning biological behaviour. GISTs have prognostic parameters, such as tumor localization, tumor diameter, mitotic index, cellularity, and pleomorphism grade.

Prognostic Factors for Large Symptomatic Gists: a Pragmatic Study of Experiences From a University Hospital Over 10 Years

Background:

Gastrointestinal stromal tumors (GISTs), which are mesenchymal neoplasms in the gastrointestinal (GI) tract account for 0.2% of all GI tumors. Several factors have been reported (mostly from studies conducted in Western countries) to be associated with survival in GISTs cases such as tumor site, staging, and tumor size. We conducted a pragmatic study, looking at a 10-year period, aimed at understanding the prognostic factors related to GISTs in a university hospital. The study population consisted of patients with large symptomatic GISTs.

Methods:

This was a retrospective study conducted at the Department of Surgery in the Khon Kaen University Hospital (Thailand). All patients diagnosed with GISTs that were treated between 2006 and 2015 were consecutively enrolled. The diagnosis of GISTs was made by examining the pathological section and immunohistochemistry results. The outcome of this study was the rate of survival after surgical treatment. Prognostic factors were determined using Cox regression analysis.

Results:

There were 124 GISTs patients treated at the university hospital during the 10-year period of the study. The median age of all patients was 54 years (range 24-83 years). Of those, 119 (95.9%) were symptomatic. Rectosigmoid GISTs accounted for 20.2% of all tumors. The median tumor size was 8 cm. A total of 68 patients (54.8%) died. The median survival time for all patients was 7.18 years (1st -3rd quartile range 6.48-7.89). There were three significant factors associated with death including male gender, liver metastasis, and peritoneal metastasis.

Conclusion:

Male gender, liver metastasis, and peritoneal metastasis were prognostic factors for large symptomatic GISTs.

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.

The epidemiology of gastrointestinal stromal tumors in Taiwan, 1998-2008: a nation-wide cancer registry-based study

Background

To investigate the incidence of gastrointestinal stromal tumors (GISTs) in Taiwan and the impact of imatinib on the overall survival (OS) of GIST patients.

Methods

GISTs were identified from the Taiwan Cancer Registry (TCR) from 1998 to 2008. The age-adjusted incidence rates and the observed OS rates were calculated. Cox proportional hazards models were applied to examine the mortality risk in three time periods (1998–2001, 2002–2004, 2005–2008) according to the application and availability of imatinib.

Results

From 1998 to 2008, 2,986 GISTs were diagnosed in Taiwan. The incidence increased from 1.13 per 100,000 in 1998 to 1.97 per 100,000 in 2008. The most common sites were stomach (47-59%), small intestine (31-38%), and colon/rectum (6-9%). The 5-year observed OS was 66.5% (60.3% for men, 74.2% for women, P < .0001). GISTs in the stomach had a better 5-year observed OS (69.4%) than those in the small intestine (65.1%) (P < .0001). The outcome of GIST improved significantly after the more widespread use of imatinib; the 5-year observed OS increased from 58.9% during 1998–2001 to 70.2% during 2005–2008 (P < .0001). Younger age, female sex, stomach location, and later diagnostic years were independent predictors of a better survival.

Conclusions

The incidence of GIST has been increasing in Taiwan, partially due to the advancement of diagnostic technology/method and the increased awareness by physicians. The outcome of GIST has improved significantly with the availability and the wider use of imatinib.

Correlation between P53 expression and malignant risk of gastrointestinal stromal tumors: evidence from 9 studies

PURPOSE

The published data about p53 expression and its potential value in malignant risk of Gastrointestinal Stromal Tumors patients seemed inconclusive. To derive a more precise estimation of the relationship between p53 and Malignant risk of GIST, a meta-analysis was performed.

MATERIALS AND METHODS

Studies have been identified by searching PubMed and Embase. Inclusive criteria were GIST patients, evaluation of p53 expression and malignant risk. The odds ratio (OR) for positive rate of p53 in NIH very low risk group vs. NIH low risk group, the odds ratio (OR) for positive rate of p53 in NIH low risk group vs. NIH Intermediate risk group and the odds ratio (OR) for positive rate of p53 in NIH Intermediate group vs. NIH high risk group were calculated with 95% confidence interval (CI) for each study as an estimation of potential value of p53 in malignant risk of GIST.

RESULTS

A total of 9 studies including 768 patients were involved in this meta-analysis. The meta-analysis of positive rate of p53 in NIH VL group vs. NIH L group did not attain significant difference (OR 0.38 95% CI, 0.11-1.28; P = 0.12 P(heterogeneity) = 0.51). However the overall OR for positive rate of p53 in NIH L group vs. NIH I group revealed that significantly elevated risks of positive p53 in NIH I group were achieved (OR 0.44 95% CI, 0.24-0.82; P = 0.009 P(heterogeneity) = 0.32). The overall OR for NIH I group vs. NIH H group was 0.62 (95% CI, 0.37-1.02; P = 0.06 P(heterogeneity) = 0.25).

CONCLUSION

The results indicate p53 overexpression correlate with the malignant risk increasing of GIST and have a primary and closest relationship within the NIH I risk group of GIST.

Predictive value of p53 expression in the risk of malignant gastrointestinal stromal tumors: Evidence from 19 studies

The current published data on p53 expression and its predictive value in the risk of malignant gastrointestinal stromal tumors (GIST) has are inconclusive. To derive a more precise estimation of the correlation between p53 and the biological behavior of GIST, a meta-analysis was performed. Studies were identified by searching PubMed and Embase. Inclusion criteria were GIST patients, and the evaluation of p53 expression and risk of malignancy. The odds ratio (OR) for a positive rate of p53 in the benign group vs. that in the malignant group and the ORs for the positive rate of p53 in the National Institutes of Health (NIH) very low risk + low risk group (VL+L) vs. the NIH intermediate risk + high risk (I+H) group were calculated with a 95% confidence interval (CI) for each study as an estimation of the predictive value of p53. A total of 19 studies including 1163 patients were involved in this meta-analysis. The overall OR for the positive rate of p53 in the malignant group vs. the benign group revealed that significantly elevated risks of positive p53 in the malignant group were achieved (OR 0.14, 95% CI: 0.06-0.31, P<0.00001, P(heterogeneity)=0.86). Moreover, significantly elevated risks of correlation between p53 expression and the NIH I+H group were achieved in the comparison of the NIH VL+L group vs. the NIH I+H group (OR, 0.25; 95% CI, 0.17-0.38; P<0.00001, P(heterogeneity)=0.04). The results indicate that p53 expression correlates with poor prognosis in GIST and has a close relationship within the NIH I+H group.

Ki67 and p53 in gastrointestinal stromal tumors--GIST

CONTEXT

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor. Cellular proliferation and apoptosis is gaining importance for predicting prognosis in several cancers.

OBJECTIVE

To investigate the Ki67 and p53 immunostaining in GISTs.

METHODS

Specimens from 40 patients with GIST were assessed for immunohistochemical expression of Ki67 and p53. The tumors were divided according the risk of recurrence in two groups: I with high or intermediate risk and; II with low or very low risk.

RESULTS

Among the 40 patients, 21 were men, the mean age was 56 years, 16 occurred in the small intestine and 13 in the stomach, 5 in the retroperitonium, 4 in the colon or rectum and 2 in the mesenterium. Thirty two tumors were from group I and 8 from group II. Half of the patients developed recurrence, being 90% of the group I (P = 0.114). The tumor Ki67 labelling index ranged from 0.02 to 0.35 (mean level 0.12). This index was marginally higher in the group I patients with recurrence (P = 0.09) compared to the patients of the same group without recurrence. p53 staining was expressed in 65% of the GISTs. A higher frequency of p53 and Ki67 had been found in the group I tumors when compared to the other group (P = 0.022; OR = 8.00 - IC 95%: 1.32-48.65).

CONCLUSION

The most common site was the small intestine and 80% had a malignant potential justifying the high recurrence observed. No significant correlation was found between p53 and overall outcome of the patients. In group I patients, the evaluation Ki67LI may be a marker of prognosis. The positivity of both markers is higher among the patients with worst prognosis than in the others.

Gastrointestinal stromal tumor in Brazil: clinicopathology, immunohistochemistry, and molecular genetics of 513 cases

The aim of the present study was to evaluate the clinicopathological, immunohistochemical, and molecular genetic features of gastrointestinal stromal tumors in Brazil and compare them with cases from other countries. Five hundred and thirteen cases were retrospectively analyzed. HE-stained sections and clinical information were reviewed and the immunohistochemical expression of CD117, CD34, smooth-muscle actin, S-100 protein, desmin, CD44v3 adhesion molecule, p53 protein, epidermal growth factor receptor, and Ki-67 antigen was studied using tissue microarrays. Mutation analysis of KIT and platelet-derived growth factor receptor-alpha genes was also performed. There was a slight female predominance (50.3%) and the median age at diagnosis was 59 years. The tumors were mainly located in the stomach (38.4%). Immunohistochemistry showed that CD117 was expressed in 95.7% of cases. Epidermal growth factor receptor expression was observed in 84.4% of tumors. p53 protein expression was found only in 2.6% of cases but all belonged to the high-risk group for aggressive behavior according to the National Institutes of Health consensus approach. No CD44v3 adhesion molecule expression was detected. KIT exon 11 mutations were the most frequent (62.2%). The present data confirm that gastrointestinal stromal tumors in Brazilian patients do not differ from tumors occurring in other countries.

Prognostic significance of p53 gene mutations and protein overexpression in localized gastrointestinal stromal tumours

AIMS

Mutation of c-kit is a relatively early event in the tumorigenesis of gastrointestinal stromal tumours (GISTs). The aim was to determine the prognostic significance of p53 alterations as an additional genetic change in GISTs.

METHODS AND RESULTS

We reviewed 125 patients with localized GISTs subjected to complete resection between 1990 and 2002. Mutational analyses of c-kit exons 9, 11, 13 and 17, p53 exons 4-8 and immunohistochemistry for p53 protein were conducted using paraffin-embedded tissues. Alterations of p53 were observed in 50 patients (40.0%). Based on the National Institutes of Health's risk category, p53 alterations were noted more frequently in the higher risk categories (P = 0.041). With a median follow-up of 56.5 months (range: 2.3-126.8), 5-year relapse-free survival (RFS) rates were 61.7% without p53 alterations, compared with only 40.2% with p53 alterations (P = 0.009). Multivariate analysis indicated that p53 alterations comprised an independent, poor prognostic factor for RFS, in addition to c-kit mutations, large size, a high mitotic count and non-gastric primary sites.

CONCLUSIONS

Alterations in p53 were more commonly observed in localized GISTs at higher risk of relapse. This suggests that they are significant as an independent, poor prognostic factor.

Hepatoma-derived growth factor is a novel prognostic factor for gastrointestinal stromal tumors

Proliferating activity as mitotic count is generally accepted as a major prognostic indicator for gastrointestinal stromal tumors (GISTs). Hepatoma-derived growth factor (HDGF) is a novel growth factor and elevated in several types of cancer. Our study was designed to elucidate the expression and prognostic role of HDGF in GISTs. A total 178 surgically resected CD117-positive GISTs specimens were collected for immunohistochemical analysis using antibodies against HDGF. The immunoreactivities were scored as labeling index (LI) and correlated with clinicopathologic parameters of GIST patients. The HDGF immunoreactivities were detected in both nucleus and cytoplasm of GISTs tissues. Besides, the nuclear and cytoplasmic HDGF was parallely upregulated in GISTs (p < 0.001). The nuclear HDGF LI were positively correlated with that of PCNA (p < 0.001) and Ki-67 (p < 0.001), tumor mitosis (p < 0.001), tumor sizes (p = 0.007) and NIH risk categories (p < 0.001). In addition, the cytoplasmic HDGF LI were also positively correlated with that of PCNA (p = 0.031) and Ki-67 (p = 0.038), tumor sizes (p = 0.003) and tumor mitosis (p = 0.015). Patients with higher HDGF levels had earlier tumor recurrence and unfavorable outcome (p < 0.05). In addition to standard prognostic factors (NIH risk categories), the nuclear HDGF LI is an independent prognostic factor for disease free and overall survivals of GIST patients after operation. We conclude that HDGF is a novel prognostic factor for GIST patients.

Expression of COX-2, PCNA, Ki-67 and p53 in gastrointestinal stromal tumors and its relationship with histopathological parameters

AIM: To investigate the expression of Cyclooxygenase-2 (COX-2), proliferating cell nuclear antigen (PCNA), Ki-67 and p53 in gastrointestinal stromal tumors (GISTs) and its relationship with histopathological parameters.

METHODS: Twenty-five GISTs were examined by light microscopy and immunohistochemistry. c-kit, CD34, SMA, S-100 protein, COX-2, PCNA, Ki-67 and p53 were detected immunohistochemically and the relationship was evaluated among histopathologic parameters such as mitotic index (MI), tumor grade, tumor size, COX-2, PCNA, Ki-67 and p53.

RESULTS: COX-2 protein expression was found in 19 of 25 (76%) of the tumors, and expression was noted in the cytoplasm of the tumor cells. p53 was significantly related to MI and tumor grade but no relationship was found between COX-2, proliferation markers and MI, tumor grade and tumor size.

CONCLUSION: COX-2 is expressed in most GISTs and it may play an important role in the proliferation and progression of these tumors or a useful marker to identify GIST. Although immunohistochemical assessment of p53 can be used for distinguishing the risk groups of GISTs, tumor size and mitotic rate should be considered at the same time.

Expression and prognostic role of molecular markers in 99 KIT-positive gastric stromal tumors in Taiwanese

AIM: To elucidate the prognostic role and relationship of three molecular markers such as tumor suppressor gene p53, proliferating cell nuclear antigen (PCNA) and Ki-67 in gastric stromal tumor.

METHODS: A total of 108 surgically resected gastric smooth muscle tumor specimens were collected from January 1987 to December 1999. Immunohistochemical studies were performed on the paraffin sections of 99 of 108 CD117-positive tumors with antibodies of p53, PCNA, and Ki-67. Immunoreactivity of three molecular markers was recorded by labeling index (LI, %) and was analyzed for clinicopathologic and survival correlation.

RESULTS: Of the 99 cases, immunostaining revealed that 52 patients (52.5%) had p53, and 37 patients (37.3%) had Ki-67 immunoreactivity (defined as >10% of LI). All patients (100%) had PCNA immunoreactivity ranging from 12% to 93% of LI, divided into high or low by median. Statistics revealed that LI of three markers positively correlate to each other (P<0.01) and to microscopic tumor mitotic counts (P <0.001). By combination, patients with ≥2 markers (positive or high) in tumors had early tumor recurrence (P <0.001) and unfavorable outcome (P <0.001). Univariate analysis indicated that patients with tumor size >5 cm (P = 0.003), tumor mitosis >5/50 HPF (P < 0.001), p53 immunoreactivity (P  = 0.001), Ki-67 immunoreactivity (P =0.026), high PCNA LI (P =0.015) and male gender (P =0.036) were six predictors for early disease recurrence. Subsequent multivariate analysis revealed that mitotic counts, tumor size, and p53 immunoreactivity were three independent prognostic factors for both disease free and overall survival of patients. By combination of three independent prognostic factors for grouping, we found higher tumor recurrence rate (P <0.001) and shorter survival (P <0.001) existed in groups with increasing factors.

CONCLUSION: We first provide the prognostic value and linkage of three molecular markers in GISTs. The combination of three factors (p53, tumor size, and tumor mitosis) provides a more powerful prediction of prognosis than any single factor does.

Gastrointestinal stromal tumors in Iceland, 1990-2003: the icelandic GIST study, a population-based incidence and pathologic risk stratification study

Gastrointestinal stromal tumor (GIST) is a newly defined clinical and pathologic entity. This study examines the whole population-based incidence of GIST as well as pathologic risk stratification schemes. All patients diagnosed in Iceland with a gastrointestinal mesenchymal tumor over the years 1990-2003 were evaluated with an immunohistochemical panel including staining for c-kit. The age-adjusted incidence of GIST was calculated. Size, mitotic rate per 50 HPF and various other pathologic parameters were evaluated. Each tumor was categorized into 1 of 4 recently defined NIH risk stratification categories. Fifty-seven of the mesenchymal gastrointestinal tumors were positive for c-kit and therefore categorized as GIST. The annual incidence for the study period is 1.1 per 100,000. The median age of patients was 65.8 years and median tumor size was 4.6 cm. Only 2 of 35 gastric tumors fall into the NIH high-risk category while half of the nongastric tumors (11 of 22) fall into this high-risk category. Eight of the 57 tumors (14%) metastasized, 7 of which were nongastric. The positive predictive value for malignant behavior of the high-risk category is 46%. The negative predictive value of low- and very-low-risk NIH category is 100%. Pathologic predictors of malignant behavior are tumor size, mitotic rate, mucosal disruption, necrosis and high cellularity. Nongastric GISTs are clearly at much higher risk of a malignant behavior than gastric GISTs. This population-based GIST study estimates the incidence of GISTs at 1.1 per 100,000 and furthermore supports the NIH consensus categories for the prediction of malignant behavior of GISTs.

Advanced-stage gastrointestinal stromal tumor treated with imatinib in a 12-year-old girl with a unique mutation of PDGFRA

A 12-year-old girl presented with a large abdominal tumor. At surgery, a huge pedunculated extraluminal tumor was found arising from the greater curvature of the stomach and invading the surrounding structures, and there were also a submucosal tumor measuring 5 x 4 x 4 cm and multiple intramural nodules beside the main tumor. These lesions, which were removed with 1.0-cm surgical margins, were immunohistochemically positive for c-kit (CD117) and CD34. A diagnosis of gastrointestinal stromal tumor (GIST) was made. The huge size of the tumor (3.6 kg in weight and 36 x 25 x 25 cm in diameter), the invasion of the surrounding structures, and the increased mitotic figures indicated the GIST had malignant potential. Sequence analysis of the polymerase chain reaction product of RNAs from the tumor cells revealed a novel platelet-derived growth factor receptor alpha (PDGFRA) mutation, which would exhibit biologic consequences similar to those of the c-kit mutation. The patient underwent a 3-month course of imatinib mesylate as adjuvant chemotherapy because of the possible risk for tumor recurrence. She is now doing well without any evidence of recurrence or metastasis 25 months after the surgery. Only 9 cases of GIST have been reported in children, and a review of those cases revealed GISTs in children would be associated with a better prognosis than in adults and that one third of pediatric GISTs presented with intestinal obstruction in the newborn period.

Gastrointestinal stromal tumor (GIST) in southern Taiwan: A clinicopathologic study of 93 resected cases

The purpose of this study was to determine the clinicopathologic features of gastrointestinal stromal tumor (GIST) in southern Taiwan. The pathology files from a medical center in southern Taiwan (1993 to 2003) were searched for primary mesenchymal tumors of the gastrointestinal tract. Hematoxylin/eosin sections and history were reviewed, and immunohistochemistry was performed using anti-CD 117, CD34, smooth muscle actin (SMA), and S-100 protein. Only primary resected GISTs were included in this study. Univariate and multivariate analyses were carried out using the T-test to evaluate the significance of primary tumor size and mitotic activity for the prediction of recurrence and metastasis. A total of 121 surgically resected primary mesenchymal tumors were identified, and 93 of these were GISTs. These 93 patients showed a slight female predominance (male: female = 1:1.2). The clinical presentations were variable and site-dependent. The most common tumor locations were the stomach (57%) and the small intestine (39%). Microscopically, 88 tumors (95%) were composed of spindle cells, the remaining five (5%) consisted of mixed epithelioid and spindle cells. No pure epithelioid type GIST was found. In addition to CD117, 66 cases (71%) were positive for CD34, 23 cases (25%) were positive for SMA, and 19 cases (21%) were positive for S-100. In a mean follow-up time of 27.3 months (median: 26 months), 19 cases (20.6%) were clinically malignant and mainly manifested as liver metastases (seven cases, 37% of malignant GISTs). Univariate analysis revealed that both primary tumor size and mitotic activity were significantly increased in the group affected by recurrence and/or metastasis (p = 0.001 and 0.035, respectively). Compared to GISTs in the western countries, those in southern Taiwan are characterized by a slight female predominance, a relatively higher frequency of small intestinal localization, a higher rate of S-100 protein expression, and a less aggressive behavior. Tumor size and mitotic activity were useful predictors of malignancy.

Analysis of prognostic and immunohistochemical factors in gastrointestinal stromal tumors with malignant potential

The aim of this study was to analyze 37 patients with malignant primary gastrointestinal stromal tumors and to compare the findings and their therapeutic implications with those previously reported. The medical records of 37 patients who were diagnosed and operated on between January 1996 and December 2002 were retrospectively reviewed. The patients' age, tumor size, type of surgery, histologic type, mitotic counts, presence of necrosis, Ki-67 proliferative index, National Institutes of Health 2001 consensus classification, immunohistochemical staining, and recurrence were examined to analyze factors affecting survival. Overall actuarial survival for all patients was 46%. When analyzed by type of resection, the complete resection group (R0 resection) had a mean overall survival of 48.2 +/- 6.18 months compared with the patients with incomplete resection (R1-R2) who survived a mean of 10.8 +/- 3.2 months (P=0.00). Univariate analysis showed development of recurrence (P=0.00), tumor size of 8 cm or greater (P=0.05), Ki-67 proliferative index greater than 0.82 (P=0.0448), desmin staining (P=0.0076), age younger than 49 years (P=0.0009), and incomplete resection (P=0.00) to be significantly correlated with a poor survival. In multivariate analysis, desmin staining (P=0.031), tumor size (P=0.033), age (P=0.01), recurrence (P=0.038), and R0 resection (P=0.02) were significant independent prognostic factors. We recommend that more careful preoperative and more frequent postoperative follow-up examinations be performed for patients with large tumors, age of younger than 49 years, and Ki-67 proliferative index greater than 0.82.

Prognostic indicators for gastrointestinal stromal tumours: a clinicopathological and immunohistochemical study of 108 resected cases of the stomach

AIMS

Whether immunohistochemical markers increase accuracy in predicting prognosis for gastrointestinal stromal tumours (GISTs) remains uncertain. However, past studies have used only small, heterogeneous patient groups. Our aim was to test previously studied and more novel morphological features as well as four immunohistochemical markers as prognostic indicators amongst a large cohort of surgically resected, gastric GISTs.

METHODS AND RESULTS

Tissues from 127 gastric mesenchymal tumours were collected retrospectively and subjected to repeat histological assessment and immunophenotyping. Further immunohistochemistry was performed for Ki67, p53, Bcl-2 and cyclin D1. Complete follow-up data were collected for 108 patients with immunophenotyped diagnoses of GIST (i.e. c-kit+ tumours). At the census point, 52 patients were alive, 24 had died from their GISTs and the remainder of other causes. Univariate analysis showed the following predicted for shorter disease-specific survival: size > or =50 mm; necrosis, no intratumoral lymphocytes; mitotic count > or =5/50 high power fields; Ki67 labelling index > or =5%; p53 immunopositivity. Of these variables, multivariate analyses showed only mitotic count and, to a lesser extent, Ki67 labelling to be independent prognostic indicators.

CONCLUSIONS

Mitotic count remains the best predictor of outcome following surgical resection of gastric GISTs. Ki67 immunohistochemistry does not provide better prognostication and p53, Bcl-2 and cyclin D1 immunohistochemistry provide no additional prognostication.