Article Type : Research Article
Authors : Alharbi H, AlGhamdi F1, Mubarah A, Alhumaidan N and Ali BI
Keywords : Gastrointestinal stromal tumor; Saudi Arabia
Background: Gastrointestinal stromal tumor
(GIST) is considered a rare disease entity, accounting for less than 3% of all
gastrointestinal neoplasms, but by far considered the most common primary
mesenchymal tumors of the gastrointestinal system. It’s sporadic more than in
neoplastic syndromes and can be found anywhere along the GI system but the
stomach is considered the most common site. Unless the tumor is unrespectable
or metastatic, surgery is the mainstay of treatment
Method: Medical records of all patients
diagnosed with GIST in Prince Sultan Military Medical City located in Riyadh
the capital of Saudi Arabia in the time between January 2015 and December 2020
were collected, including patients' age, gender, clinical presentations,
radiological investigations and features, histopathological findings and
Immunohistochemically markers.
Results: A 39 cases found, with 19 males
and 20 females. All were Saudi with majority of patients which was 23 (59%)
were diagnosed between the age of 40 and 60 years. Most common location was
stomach 22 (56.4%), followed by 8 (20.5%) cases in small bowl. Using NIH
criteria for GIST risk assessment for malignant behaviour, we stratified our
cases into high, intermediate, low, and very low risk (28.2%, 10.2%, 33.3%, and
20.5% respectively).
Conclusion: This retrospective review
confirms multiple GIST features that correlate closely with other published
studies. Further prospective studies needed with higher sample size and unified
parameters for better understanding of GIST tumors features, management, and
prognosis.
Gastrointestinal stromal
tumor (GIST) is considered a rare disease entity, accounting for less than 3%
of all gastrointestinal neoplasms, but by far considered the most common
primary mesenchymal tumors of the gastrointestinal system and known to be derived
from the interstitial cells of Cajal which functions as the pacemaker cell [1].
It’s sporadic in incidence but might sometimes be seen as a part of other
neoplastic syndromes. The disease process is thought to be due to mutations of
proto-oncogenes c-KIT or platelet-derived growth factor receptor alpha
polypeptide, which increase tyrosine kinase receptor activity leading to
continues proliferation of stem cells that differentiate into the interstitial
cells of cajal [2]. These tumors can be found anywhere along the GI system, but
the stomach is considered the most common site (60%), followed by the small
intestine, duodenum, colon/ rectum and very rarely from the esophagus, few
primary cases has been reported to originate from the omentum, mesentery, and retroperitoneum
[3]. They show a greater incidence among men and dark-skinned population with
age range between 40-80 years with 63 being the median age [4]. GIST has a wide
range of clinical presentations that vary from symptoms that requires emergency
visits like bowel obstruction, upper or lower GI bleeding or idiopathic
spontaneous intra-abdominal bleeding to patients being asymptomatic and
discovered incidentally during radiological or endoscopic investigations for
other symptoms [5]. Many imaging modalities can help diagnosing GIST like CT
scans, PET, MRI, and ultrasound. CT especially in small bowel GIST gives the
highest yield among other modalities, it also provides information about
metastasis and local invasion [6]. Immuno histology together with pathology
results are often diagnostic, and the mainstay of diagnosis is identifying CD
117 antigen (an epitope of KIT receptor tyrosine kinase) with approximately 95
% cases positive for the antigen. The main histopathological variants that are
usually found are spindle cell, epithelioid and mixed spindle, and epithelioid
variants [7]. Unless the tumor is unrespectable or metastatic, surgery is the
mainstay of treatment with R0 resection, and no lymph node dissection is
recommended. The use of adjuvant imatinib (tyrosine kinase inhibitors) in
high-risk group patients showed an improved survival and a decrease in the
recurrence rates. In those who has an unrespectable or metastatic disease,
imatinib has been the primary approach as a neoadjuvant treatment [8]. In this
study, our aim is to study the cases of GIST in our center in regard of their
prevalence, clinical and radiological and histological features, and prognosis.
The medical records of
all patients diagnosed with GIST and confirmed by histopathology, in Prince
Sultan Military Medical City located in Riyadh the capital of Saudi Arabia. All
cases of confirmed GIST between January 2015 and December 2020 were collected
retrospectively. The collected data included patients' age, gender, clinical
presentations, radiological investigations and features, histopathological
findings and Immunohistochemical markers such as CD117, DOG-1, DOG-7, CD34,
SMA, desmin and S-100 proteins, surgical procedures, prognosis. Inclusion
criteria included all patients diagnosed with GIST that was found in imaging,
endoscopy or post-operative finding in any location which was confirmed by
histopathological report. Exclusion criteria used were all patients who had
inconclusive histopathological report to confirm GIST. This study was approved
by the ethical committee in our hospital.
We included 39 cases of GIST tumors in our study. Gender wise, 19 males and 20 females included with all the cases were Saudi in nationality. Majority of patients were diagnosed between the age of 40 and 60 years, which was 23 (59%) patients out of the 39 cases followed by 14 (35.9%) patients above the age of 60 years. Most of the GIST tumors were in stomach 22 (56.4%), followed by 8 (20.5%) cases in small bowel, followed by 3 cases found in the abdomen with no clear origin identified, with few cases of GIST seen in the duodenum, rectum, retroperitoneal, liver or lower esophagus. Most of the patients presented as abdominal pain, gastrointestinal (GI) bleeding or incidentally found in imaging, endoscopy or intra-operatively, with the most common presentation was abdominal pain in 46.2% of patients followed by GI bleeding in 28.2%, where incidental GIST found in imaging in 2 cases, and found in gastric specimen post laparoscopic sleeve gastrectomy in 2 cases, and found incidentally intra-operatively in jejunum of one case during Whipple procedure for pancreatic head cancer. The median size was the highest in one single case of lower esophageal GIST tumor whish was reaching 18 cm, followed by the intra-abdominal GIST tumors with unknown origin in which their median size was 15 cm, with the gastric tumors median size was 5 cm, and small bowel tumors of 3 cm (Table 1).
Table 1: Demographics and clinical presentation of GIST patients (n 39).
Demographics and clinical presentation of GIST patients (n 39) |
||
Age |
< 40 years |
2 (5.1%) |
40 – 49 years |
13 (33.3%) |
|
50-60 years |
10 (25.6%) |
|
> 60 years |
14 (35.9%) |
|
Gender |
Male |
19 (48.7%) |
Female |
20 (52.4%) |
|
Tumor Location |
Stomach |
22 (56.4%) |
Duodenum |
2 (5.1%) |
|
Small bowel |
8 (20.5%) |
|
Liver |
1 (2.6%) |
|
Intra-abdominal
with unknown origin |
3 (7.7%) |
|
Retroperitoneal |
1 (2.6%) |
|
Lower Esophagus |
1 (2.6%) |
|
Rectum |
1 (2.6%) |
|
Median size (cm) |
Stomach |
5 |
Duodenum |
2.5 |
|
Small bowel |
3 |
|
Liver |
1 |
|
Intra-abdominal
with unknown origin |
16 |
|
Retroperitoneal |
8 |
|
Lower Esophagus |
18 |
|
Rectum |
2 |
|
Presentation |
GI Bleeding |
11 (28.2%) |
Abdominal pain |
18 (46.2%) |
|
Incidental (radiology, endoscopy, post operatively) |
5 (12.8%) |
|
Type of Surgery |
Elective |
27 (69.2%) |
Emergency |
4 (10.3%) |
|
Not operated |
8 (20.5%) |
|
Metastasis |
Yes |
8 (20.5%) |
No |
31 (79.5%) |
|
Recurrence |
Yes |
5 (12.8%) |
No |
27 (69.2%) |
|
Mitosis (?5 vs >5
per 50 HPF) |
Stomach |
15 vs 5 |
Duodenum |
2 vs 0 |
|
Small bowel |
3 vs 3 |
|
Rectum |
0 vs 1 |
|
CD type positive |
CD 117 |
39 (100%) |
DOG-1 |
28 (71.8%) |
|
CD 34 |
20 (51.3%) |
|
SMA |
6 (15.3%) |
|
DOG-7 |
4 (10.2%) |
|
h-Caldesmin |
2 (5.1%) |
|
Desmin |
1 (2.6%) |
|
S 100 |
0 (0%) |
|
Type of cells in
histopathology |
Spindle-cell |
25 (64.1%) |
Epitheloid |
0 (0%) |
|
Mixed |
8 (20.5%) |
Table 2: NIH-Fletcher criteria for GIST risk assessment.
NIH-Fletcher criteria for GIST risk assessment |
|||
Risk Category |
Primary Tumor Size (cm) |
Mitotic Count (per 50 HPF) |
No. (%) |
Very Low Risk |
< 2 |
< 5 |
8 (20.5%) |
Low Risk |
2 - 5 |
< 5 |
13 (33.3%) |
Intermediate Risk |
< 5 |
6 – 10 |
4 (10.3%) |
5 - 10 |
< 5 |
||
High Risk |
> 5 |
> 5 |
11 (28.2%) |
> 10 |
Any mitotic rate |
||
Any size |
> 10 |
To the best of our
knowledge, this is first retrospective study reviewing the gastrointestinal
tumors in detail in the central region of Saudi Arabia, and the second over the
country. The study was done in Prince Sultan Military Medical City located in Riyadh
which is the capital city of Saudi Arabia; as a military hospital, all the
cases collected were Saudi in nationality given the strict eligibility rules
[9,10]. There was no significant difference in number of cases between males
and females, which was 19 and 20 respectively, although there was male
predominance reported in the other study in western region of Saudi Arabia and
in another neighbouring gulf country, however there was no significant gender
predominance in large scale studies done in Iceland, Sweden and in a study done
in Wuhan in China [1,11,12]. Most of the patients in our study were diagnosed
at the age of 40-60 year, with only 2 cases below 40 and 14 cases above 60
years, like what was shown in Qatari and Egyptian studies where they had the
mean age of 48, and to have the highest incidence between the age of 50-60
years in the studies done in Wuhan and Shanxi Province [13,14]. From the 39
cases we had, 22 (56.4%) had GIST located in stomach followed by 8 (20.5%) in
the small bowel which was correlating with all the studies we a crossed in the
literature either in the region or internationally. In the regional study in
Qatar [10] 85.4% of cases presented with abdominal pain, followed by GI
bleeding in 54.2% of cases, with our study in the line of these clinical
behaviours. GIST can be asymptomatic and found incidentally in endoscopy,
imaging or intra-operatively as in 12.8% of our cases, as the size and location
and in which if it is intraluminal or extra luminal contribute to its presentation.
Incidental finding reported to reach 18.7% in a systematic review published in
2015 [15]. Metastasis can be presented at diagnoses in approximately 20% of
cases, in which was the case in 20.5% of our patients. For the risk assessment
of potential malignant behaviour of GIST tumors, multiple criteria were found,
in which the National Institute of Health criteria (NIH-Fletcher) is one of the
well-recognized criteria for GIST risk stratification into very low, low,
intermediate, and high risk. NIH criteria uses the tumor size and mitotic rate
as prognostic factors, where it has been noticed that the malignant potential
and the recurrence rate are higher in tumors that are 5-10 cm in size with
mitosis of 10/50 HPF with recurrence rate being almost 80% in these high-risk
groups [16]. In our study, 13 (33.3%) cases where stratified into low risk
followed by 11 (28.2%) cases falling into high-risk group. Although regional
studies in Western Saudi Arabia and in Qatar [9,10] showed majority of cases
were stratified under high-risk group compared to non-high risk, variation was
noticed with the Sweden and Iceland studies showed the non-high risk were most
cases compared to the high risk [11,12].
This retrospective review
confirms multiple GIST features including gender predominance, clinical
behavior and histopathological features that correlate closely with other
published studies. Diagnosis of GIST tumors need high clinical suspicion and
good usage of investigations. Further prospective studies needed with higher
sample size and unified parameters for better understanding of GIST tumors
features, management, and prognosis.
The authors declared no
conflict of interest and no financial issues to disclose.