Gastric Cancer in Southern Saudi Arabia
Abstract
A total of 84 cases of primary gastric cancer were diagnosed in the histopathology laboratory of Asir Central Hospital over a five year period (1987 to 1991). Seventy-two patients (86%) were Saudis and 12 cases (14%) were non-Saudis. The mean age of the patients included in this study was 60 years with a range of 22 to 85 years and a male:female ratio of 4.6:1. Intestinal adenocarcinoma occurred in 63 patients (75%) followed by malignant lymphomas in 12 cases (14%) and diffuse adenocarcinoma in nine cases (11%). The gastric antrum was the most common site affected (47%), followed by gastric corpus (27%), cardia (14%), and fundus (12%). Comparisons of our findings to similar reports from other provinces of Saudi Arabia and other countries are discussed.
Introduction
Gastric cancer is a leading cause of death worldwide.1 Variations in the pattern of gastric cancer exist between developed countries and developing countries.2 Environmental as well as genetic and racial factors play an important role in the causation of gastric cancer.3 Comparative studies of the pattern of gastric cancer in various populations might help in better understanding of environmental and genetic or racial factors contributing to the evolution of gastric cancer.
Several reports from the Kingdom of Saudi Arabia have recently studied general patterns of cancer,4–6 and patterns of gastrointestinal tract malignancies.7–9 Only a few reports have been devoted to the study of the pattern of gastric cancer.10 The current study describes the general pattern of primary gastric cancer in Southern Saudi Arabia for the first time. Our findings of patients’ age, sex, nationality, location, and histological type of gastric cancer are compared to findings from other provinces of the Kingdom as well as from other countries.
Patients and Methods
The current study included 84 cases of primary gastric malignancy diagnosed at Asir Central Hospital during a five year period (1987 to 1991). Diagnosis of cancer was made histologically in all 84 cases (34 cases had gastrectomy and in the remaining 50 cases, the diagnosis was made in endoscopic biopsies only). All specimens were fixed in 10% formalin and stained with hematoxylin and eosin (H&E). Special stains including immunohistochemical markers were done when needed. Classification of gastric carcinoma into intestinal and diffuse type was made according to the criteria of Lauren.11 All cases of malignant lymphoma were primary gastric lymphoma as the patients did not have disseminated disease at the time of presentation, no generalized lymphadenopathy, negative bone marrow biopsies and no internal lymphadenopathy by computed tomography (CT) scanning and x-rays of the chest, abdomen and pelvis. The medical records and endoscopy reports were reviewed to identify the patients’ age, sex, nationality and location of the tumor. The location of the tumor was defined as the part of the stomach containing the major portion of the tumor. The latter was assessed pathologically in 34 resected specimens and endoscopically in the remaining 50 cases. These 50 cases were either referred to other institutions for further therapy or were lost to follow-up. In order to evaluate our confidence in histological classification of adenocarcinoma in endoscopic biopsies, we have independently reviewed the endoscopic biopsies of the 34 cases that have undergone subsequent gastrectomy and tumor typing in biopsies and gastrectomy specimens were compared. The data analysis included the patients’ age, sex, nationality, endoscopic and/or pathologic location of the tumor, and their histological types. Our data are expressed in total absolute numbers and/or percentage (crude relative) frequencies.
Results
Distribution of various histological types of gastric cancer according to age, sex, and nationality is shown in Table 1. A total of 75% of our 84 patients had intestinal adenocarcinoma, 14% had primary non-Hodgkin malignant lymphoma (NHL) of the stomach and the remaining nine patients (11%) had diffuse gastric adenocarcinoma. The latter classification of adenocarcinoma into intestinal and diffuse type was made according to the histologic criteria set by Lauren.11 Mean age of intestinal adenocarcinoma cases was 64 years compared to 55 and 58 years for diffuse adenocarcinoma and gastric NHL respectively. The male:female ratio was 4.6:1, 4.7:1, 3:1 and 8:1 for all cases of intestinal adenocarcinoma, NHL and diffuse adenocarcinoma respectively. The Saudi:non-Saudi ratio was 6:1, 11.6:1 and 1.25:1 in all cases of intestinal adenocarcinoma, NHL and diffuse adenocarcinoma respectively. All 24 cases of intestinal adenocarcinoma were correctly diagnosed in pregastrectomy endoscopic biopsies when compared to diagnosis in gastrectomy specimens. One case diagnosed in biopsy as intestinal adenocarcinoma turned out to be of the diffuse type in subsequent gastrectomy. Six diffuse adenocarcinomas and three NHL cases were correctly diagnosed in endoscopic biopsies when compared to diagnosis in gastrectomy specimens. Grading of 24 intestinal adenocarcinoma cases diagnosed in gastrectomy specimens was: one case of well differentiated, 18 cases of moderately differentiated, and five cases of poorly differentiated. None of the 31 cases of adenocarcinoma diagnosed in gastrectomy specimens were of early gastric cancer type.
| Histopathologic diagnosis | Age (years) | Nationality | Sex | Total Number of Cases | |||
|---|---|---|---|---|---|---|---|
| Mean | Range | Saudi | Non-Saudi | Male | Female | ||
| Intestinal type adenocarcinoma | 64 | 25–85 | 58 (92) | 5 (8) | 52 (83) | 11 (17) | 63 (75) |
| Diffuse type adenocarcinoma | 55 | 28–75 | 5 (55.5) | 4 (44.5) | 8 (89) | 1 (11) | 9 (11) |
| Malignant lymphoma | 58 | 22–80 | 9 (75) | 3 (25) | 9 (75) | 3 (25) | 12 (14) |
| Total | 60 | 22–85 | 72 (86) | 12 (14) | 69 (82) | 15 (18) | 84 (100) |
Table 2 shows the distribution of various histologic types of gastric cancer according to the gastric site affected. Forty-seven percent of all cancer cases occurred in the gastric antrum, which was also the most common location of intestinal adenocarcinoma. The antrum was affected in only 33% of cases of diffuse adenocarcinoma and NHL.
| Histopathologic type | Cardia | Fundas | Body | Antrum | Total |
|---|---|---|---|---|---|
| Adenocarcinoma “Intestinal type” | 11 (17) | 7 (11) | 13 (21) | 32 (51) | 63 (100) |
| Adenocarcinoma “Diffuse type” | 1 (11) | 2 (23) | 3 (33) | 3 (33) | 9 (100) |
| Malignant lymphoma | - | 1 (8) | 7 (59) | 4 (33) | 12 (100) |
| Total | 12 (14) | 10 (12) | 23 (27) | 39 (47) | 84 (100) |
Discussion
The general pattern of cancer and pattern of primary gastrointestinal tract cancer in Asir Province have been recently published.12,13 Gastric cancer is the fifth ranking type of cancer in the Asir region, representing 6.7% of all cancer cases. Gastric cancer represented 27% of primary gastrointestinal tract cancer cases with gastric to colorectal cancer ratio of 1.3:1. In developed countries, colorectal cancer accounts for more than 75% of primary gastrointestinal tract cancer compared to only 10% for gastric malignancy.
Features of gastric cancer among our patients are similar to features reported from high risk areas worldwide.14–16 These include median age in the seventh decade (60 years), males more frequently affected than females (4.6:1), intestinal type adenocarcinoma more common than diffuse type (7:1) and distal location is more frequent than proximal location (1.8:1). Non-Hodgkin malignant lymphoma of the stomach represented 14% of our patients, whereas in Western countries, NHL represents only 2% to 5% of gastric malignancy.17 In a recent study from the Riyadh area, NHL represented 22% of all gastric cancer cases.10
Features of gastric adenocarcinoma in our patients are significantly different when compared to the Riyadh study10 regarding patients’ nationality, histopathologic types, tumor location, sex, and age. In our study, the ratio of Saudis:non-Saudis was 7:1 compared to 1.75:1 in the Riyadh area, and the ratio of intestinal type: diffuse adenocarcinoma among our Saudi patients was 11.6:1 compared to a ratio of 1.8:1 among Saudi patients from the Riyadh area. Distal (antral) intestinal adenocarcinoma was seen in 51% of our cases compared to only 23% of the patients from the Riyadh area. Mean age of our cases with intestinal adenocarcinoma was 64 years compared to 55.6 years in the Riyadh area. In our study, diffuse adenocarcinoma was eightfold higher in males compared to females, whereas in the Riyadh area, this ratio was 2.5:1.
In Western countries where the incidence of gastric cancer is declining, the patient’s age, the male:female ratio, the intestinal: diffuse adenocarcinoma ratio and the distal:proximal tumor location ratio of gastric carcinoma have all decreased.18–21 This trend is noted in Saudi patients from the Riyadh area but not in our Saudi patients. In our study, Saudi patients represented 92% of intestinal and 55% of diffuse gastric adenocarcinoma whereas in the Riyadh area, Saudi nationals represented 50% and 86% of intestinal and diffuse adenocarcinoma respectively. Furthermore, Saudis represented 88% of our gastric adenocarcinoma cases compared to 62% in the Riyadh study. Features of gastric carcinoma in our Saudi patients are similar to those reported among high risk populations worldwide. Our speculations are that factors responsible for the decline of gastric cancer in Western countries are operating in the Riyadh area but are not operating in Asir Province. These factors include dietary habits, socioeconomic status, and the presence of Helicobacter pylori associated gastritis.22–24
In conclusion, our study has described for the first time the general pattern of gastric cancer in Southern Saudi Arabia with features comparable to those seen in high risk populations worldwide.14–16 Significant differences were seen when our results were compared to those recently reported from the Riyadh area.10 Similar differences were noted in countries where the incidence of gastric cancer has declined. These differences should be further investigated considering various geographical and demographical features of different provinces of the Kingdom of Saudi Arabia.
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