Helicobacter pylori and precancerous conditions of the stomach: the frequency of infection in a cross-sectional study of 79 consecutive patients with chronic antral gastritis in Yaoundé, Cameroon

Introduction The study aimed at determining the different types of precancerous conditions of the stomach and searches the frequency of Helicobacter pylori in these lesions in patients with chronic antral gastritis in Yaounde, Cameroon. Methods Five gastric biopsies were performed during upper gastrointestinal endoscopy for pathology and fixed in formol 10% before being coated in paraffin. Both the modified Giemsa and Periodic acid of Shift – Alkaline blue stains were used for the histological diagnosis of Helicobacter pylori infection. Hematoxylyn and eosin stain was used to determine the activity of gastritis, atrophic gastritis and intestinal metaplasia in accordance to the Sydney's classification of gastritis. Data were analysed using both the Epi info 6.04 and Excel 2007 softwares. Means and their standard deviations, medians and their interquartiles (IQR) were calculated. Proportions were established for qualitative variables and chi square analysis done in this study with a p value set at 0.05. Results Seventy-nine patients with chronic antral gastritis were enrolled, of which 43 (54.4%) were male, median age: 43 years (range from 21 to 70 years). The rate of atrophic gastritis was 74.7% (59/79). The activity of atrophic gastritis was mild in 47.5% (28/59) of cases, moderate in 47.5% (28/59) and severe in 5% (5/59). Intestinal metaplasia and follicular gastritis were present in 6.3% (5/79), and 10.1% (8/79), respectively. Concerning Helicobacter pylori infection, 71.2% (42/59) of patients with atrophic gastritis tested positive against 28.8% (17/59) who tested negative (p = 0.00003). Helicobacter pylori infection was related to the severity of gastric atrophy (p = 0.0001). Among patients with intestinal metaplasia and follicular gastritis, the proportion of those who tested positive for Helicobacter pylori infection was 80% (4/5), and 75% (6/8), respectively. There were no significant differences in the occurrence of atrophic gastritis according to age groups (p = 0.908). Conclusion This study concludes that atrophic gastritis, which is most often caused by Helicobacter pylori, is the most frequent precancerous condition of stomach in Cameroon. Routine gastric sampling for pathologic analysis is mandatory for effective diagnosis and surveillance of Helicobacter pylori infection and precancerous conditions of the stomach.

The histological sequence which leads to the occurrence of gastric cancer has been elucidated [1]. With regards to the pathogenesis of the intestinal types of carcinoma, it is known that atrophic gastritis is the early step, followed by intestinal metaplasia, then dysplasia before the appearance of gastric carcinoma [2][3][4][5]. Atrophic gastritis and intestinal metaplasia are thus considered early markers of gastric cancer, being precancerous conditions [6]. Pathologic analysis of gastric specimens is fundamental in diagnosing chronic gastritis, as its helps classify lesions according to the degree of severity, which vary from superficial gastritis to severe atrophic gastritis [7]. Conventional endoscopy is inadequate in establishing the extent of microscopic lesions.
H. pylori is highly endemic in Cameroon [8]. Prospective studies carried out using serological data have clearly established that H. pylori constantly leads to gastritis and is a major risk factor of both the intestinal and diffuse types of gastric cancer [9].
Furthermore, H. pylori has been considered by the World Health Organization (WHO) as a carcinogen, as its accounts for most gastric cancers. Its eradication will mostly be beneficial in preventing gastric cancer before the appearance of precancerous conditions [10].
However, despite the aforementioned facts, no endoscopic algorithm for the evaluation of gastritis exists in our country.
Pathologic analysis of gastric specimens is not routinely practiced.
Conventional endoscopy coupled to H. pylori detection using the rapid urease test are the only routinely practiced investigations. In the absence of pathology and chromoendoscopy, establishing the existence of precancerous conditions of the stomach in our daily practice is scarce [11].
We thus determined, through a cross-sectional study, the prevalence of atrophic gastritis, intestinal metaplasia and follicular gastritis in our environment, and also determine the frequency of H. pylori in these lesions in patient with chronic antral gastritis using the Sydney classification to evaluate gastritis.

Methods
It was a cross-sectional study carried out from January 2013 to

Helicobacter pylori infection and precancerous conditions of the stomach in chronic antral gastritis
The relation between H. pylori infection and the occurrence of precancerous conditions of the stomach is portrayed on

Discussion
In Cameroon, the incidence, prevalence and mortality of gastric cancer has not been clearly established, although gastric cancer has been reported to be the second most common gastrointestinal malignancy [14,15]. In Europe, notably in France where data exists, gastric cancer is the fourth most common gastrointestinal cancer, with a poor prognosis, having a 5-years survival rate of about 25% [16 -18]. The histological sequence leading to gastric cancer has been established, and passes through precancerous conditions [1,4]. It successively passes through atrophic gastritis, intestinal metaplasia, dysplasia before carcinoma [1 -3].
In this study, we found a high rate of atrophic gastritis (74.7%) in patients with chronic antral gastritis, but intestinal metaplasia (6.3%) and follicular gastritis (10.1%) were rare. This finding is similar to those found in low risk groups for gastric cancer.
Paradoxically, it is different from the findings of a study in Cote d'Ivoire, a country whose settings are similar to ours and where, these lesions were very frequent [19]. It is known that the distribution of precancerous conditions of the stomach varies with respect to countries [17,18,20]. In very high risk groups like Japan and China, and certain high risk groups (blacks and Hispanics) in the United States of America, the rate of precancerous conditions of the stomach is generally very high [20 -23]. Discrepancies in the diagnosis of precancerous conditions of the stomach may also be Page number not for citation purposes 4 related to the site of gastric biopsy. The angularis, for instance, habours more precancerous conditions than the body and the antrum [24]. In this study, analysis was limited to the antrum this may explain ours results and may limit the value of our findings.
Also, the relatively small sample of this study constitutes a limit.
H. pylori infection is responsible for 80% of atrophic gastritis and is related to the development of precancerous conditions of the stomach and their progression to carcinoma [3,5,9,19,24]. The association between H. pylori infection and atrophic gastritis or intestinal metaplasia increases the risk of gastric cancer to five -sixfold [3,6,18,25]. H. pylori infection is both related to the severity of histological lesions and the activity of chronic antral gastritis [3,9,25,26]. Results of this study indicated that H. Pylori infection is frequent in precancerous conditions of the stomach and it's associated to the severity of histological lesions of the stomach (71.2% in atrophic gastritis and 80% in intestinal metaplasia).
In western countries, the majority of precancerous conditions of the stomach and gastric cancers are diagnosed beyond 75 years [16 -18]. In this study, we found a high rate of precancerous conditions of the stomach before the age of 60 years. This early onset of the development of H. pylori related gastric cancer has been clearly established in many studies carried out in other developing countries [5,8,19,20]. Intestinal metaplasia was more frequent among female patients (80%), though this could not be accounted for.