Background Gastric atrophy and intestinal metaplasia (IM) are preneoplastic conditions in the development of gastric cancer. Histopathological assessment is based on the updated Sydney system and superordinate staging systems, operative link on gastritis assessment (OLGA) and operative link on gastritis assessment using IM (OLGIM), all requiring a biopsy from the incisura angularis (angulus).
Aim To determine the value of the angulus biopsy for the detection of preneoplastic conditions and cancer risk evaluation using OLGA and OLGIM prospectively.
Methods Biopsies from antrum (2), angulus (1) and corpus (2) were obtained from 213 patients (age 19–94 years, median 54 years, female to male ratio 138:75) undergoing upper endoscopy. Histological assessment according to the updated Sydney system, OLGA and OLGIM staging was performed by gastrointestinal pathologists. Statistical analysis used exact confidence limits for dichotomous variables and repeated measurement analysis of variance.
Results 8% of the cases with atrophic gastritis and 3% with IM (17 vs 6/213) would have been missed without the angulus biopsy. More patients were diagnosed with a preneoplastic condition when the angulus biopsy was considered (13.1%, CI 8.9% to 18.4%), but the grade of atrophy, if present at both sides, did not vary significantly in angulus and antrum. OLGA and OLGIM scores dropped significantly when recalculated without the angulus (difference in means±SD 0.131±0.402 and 0.075±0.313, respectively). The impact on the identification of high-risk stages is limited.
Conclusions The angulus biopsy adds to the detection of mild gastric atrophy in particular. It allows identifying a small additional number of patients with high-risk gastritis.
- HELICOBACTER PYLORI
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Atrophic gastritis (AG) and intestinal metaplasia (IM) are preneoplastic conditions of the gastric mucosa, mostly associated with the infection with Helicobacter pylori. The prevalence of these conditions highly varies in different geographical regions, and is related to the infection rates with H pylori as well as environmental factors. AG and IM are associated with an increased risk of development of gastric cancer (GC). The annual incidence of GC for gastric atrophy is 0.1% and for IM 0.25% in Central Europe.1
The risk of cancer is dependent on the severity and extent of gastric premalignant conditions. The histological assessment of gastritis, terminology and biopsy sampling has been standardised in the updated Sydney system2 and in superordinate staging systems such as operative link on gastritis assessment (OLGA)3 and operative link on gastritis assessment using IM (OLGIM)4 for the cancer risk assessment.
Antral atrophy carries a substantially lower risk of GC than severe atrophy of the oxyntic mucosa in the corpus.5–7 However, the region of incisura angularis is reported to be a site of predilection for the detection of AG and IM,2 ,8 and thus is recommended to be examined in combination with two biopsies from antrum and corpus in the updated Sydney system, OLGA and OLGIM.
OLGA (using atrophy) and OLGIM are histological staging systems for gastritis3 ,4 proposed for the prognostic assessment concerning the risk of GC. For OLGA, it is demonstrated that all new cases of GC arose from high OLGA stages (III and IV) in a prospective follow-up period over 12 years.9 For OLGIM, it was shown that within a period of 6 years, 86% (six out of seven) new cases of dysplasia appeared in high-risk OLGIM stages (III and IV).4 Another study from the same group also observed a significant progression of IM in 67% of patients with OLGIM stages III and IV after a period of 3 years.10
In the recent European Guidelines for the management of preneoplastic conditions and lesions in the stomach,11 a biopsy from the angulus is optional, but not a general recommendation for the biopsy protocol. Therefore, we conducted this study prospectively in order to evaluate the value and diagnostic contribution of the angulus biopsy in detection of preneoplastic conditions and cancer-risk assessment.
Material and methods
Study design and patients
Two hundred and thirteen patients indicated for upper endoscopy for various clinical reasons were enrolled prospectively from Jul 2011 to Dec 2012. The study protocol was conducted according to the Declaration of Helsinki, and approved by the ethic board of the Otto-von-Guericke University.
All subjects underwent upper endoscopy, and gave their written informed consent before entering the study. The following exclusion criteria were applied: cancer, operated stomach, irradiation of the upper abdomen, immunosuppressive therapy, oral anticoagulation and antibiotic therapy in the last 2 weeks before entering the study. Ongoing or past proton pump inhibitor (PPI) therapy was not an exclusion criterion as most patients were already treated with PPI before being appointed for upper endoscopic examination. Standard video gastroscopes (GIF Q145, GIF 160 and GIF Q180 HD; Olympus Medical, Hamburg, Germany) as well as standard oval fenestrated cup forceps with a needle (Olympus SwingJaw 2.8 mm FB-240 K_A) were used.
Biopsies from antrum, corpus and incisura angularis were obtained as required for the updated Sydney system (lesser and larger curvature of the antrum at 3 cm distance from the pylorus, larger and lesser curvature of the middle corpus and one biopsy from the angulus), and immediately fixed in buffered formalin. Furthermore, two biopsies (various sites of antrum and corpus) were taken for the rapid urease test and H pylori culture each. Serum from 202 patients was available for H pylori antibodies testing.
Histological assessment was performed by trained gastrointestinal pathologists. Pathologists had only access to the demographic data of a patient as well as a short description of the endoscopic finding at the time point of histological assessment. Sections were stained with H&E, the modified Giemsa method for determination of H pylori status and periodic acid-Schiff stain (PAS). Grading of polymorphonuclear infiltration (activity), mononuclear infiltration (chronicity), atrophy and IM were performed on a visual analogue scale according to the updated Sydney system (0=none, 1=mild, 2=moderate and 3=severe). Pathologists reported one finding per site and duplicate biopsy. A mild scattered lymphocyte infiltration was not considered an abnormal finding in this study when no other pathologies were present. Polymorphonuclear cell infiltration (activity) and/or moderate lymphocyte infiltration defined chronic gastritis if no preneoplastic condition was present. Eight cases with GC and 11 cases with AG/IM had endoscopic evidence of non-malignant duodenal or gastric ulcer (15 stomach ulcers, two duodenal ulcers and two stomach and duodenal ulcers).
Diagnosis of gastritis was determined according to the histological findings. The extent of AG and IM at each biopsy site was used to determine the OLGA and OLGIM stages as described by the authors.4 ,12 The angulus biopsy always represented the antral compartment, and was considered together with the duplicate antrum biopsy for the definition of the percentage of antral atrophic metaplastic lesions and consequently the OLGA and OLGIM stage.
H pylori status
H pylori status was tested by various methods in this study: histology (as described above), rapid urease test during endoscopy, culture and serology. The first antrum and corpus biopsies were taken separately, and processed immediately in separate tubes (1.5 mL NaCl 0.9%) and sent to the Institute of Microbiology for H pylori culture. Gastric biopsy specimen was cultured on Columbia agar-based medium containing 10 vol% washed human erythrocytes and 10 vol% heat-inactivated horse serum. Plates were incubated under microaerophilic conditions at 37°C using CampyGen gasbags (Oxoid, Germany), and examined every 2–3 days for maximum 14 days. H pylori were identified by typical morphology on Gram stain and positive urease, oxidase and catalase tests.
One antrum and one corpus biopsy were tested together for urease activity during endoscopy (HUT; Astra Zeneca, Wedel, Germany); test results were obtained visually after 4 h. Five to seven millilitres of venous blood from each patient were used for serum preparation and detection of IgG antibodies against H pylori with ELISA (catalogue number 601040; Biohit, Rosbach, Germany) following the manufacturer's instruction. According to the kit information, results of ≥30 enzyme-linked immunosorbent assay (EIA) were regarded positive and <30 EIA as negative.
H pylori status was defined positive when one or more of the tests were positive (active infection and/or positive serology).
The description of the clinical characteristics has the form mean±SD for continuous variables or n (%) for variables with discrete levels. A contingency table represents the results of the histological diagnosis according to antrum+corpus (AC) and antrum+angulus+corpus (AAC) protocols. The exact confidence limits for dichotomous variables were calculated according to Clopper–Pearson for binomial proportions. These describe the agreement and the difference between the two biopsy protocols.
Parametric data (Sydney system scores) were analysed by comparison of means using the general linear models procedure (repeated measurement analysis of variance (ANOVA)) for location of biopsy as repeated factor. For the comparison of OLGA and OLGIM stages, we used a paired t test. The parameters have only an approximate metric distribution. For this reason, the interpretation of the results was done in an exploratory way. For the comparison between OLGA and OLGIM staging, we applied the Fisher's exact test. All statistical decisions were made two tailed with a critical probability of α=5% without α—adjustment. The statistical analyses were carried out using the SAS Software V.9.3 (SAS Institute, Cary, North Carolina).
Disease groups and H pylori status
The study population comprises 213 patients (75 male, 138 female; age range 19–94 years, median 54 years, mean 55 years), of which 80 had normal gastric mucosa and 54 had chronic gastritis. Preneoplastic conditions were found in 79/213 patients, a prevalence of 37% in the study population. Clinical characteristics and H pylori status in the disease groups are presented in table 1.
We simulated two different biopsy protocols by reevaluating the diagnosis based on four biopsy samples (two from antrum and two from corpus, abbreviated as AC) versus the standard protocol of five biopsies (two antrum, one angulus, two corpus, AAC). Patients’ diagnosis according to the same histological criteria depending on the biopsy protocol is shown in table 2. The protocols showed an overall consistency of 86.9% (81.6–91.1). However, 28 patients (13.1%, CI 8.9% to 18.4%) were misdiagnosed when the angulus biopsy was not taken into account. The major inconsistency was found in the group with preneoplastic conditions directed to a shift to ‘normal’ through the AC protocol in 23 cases. The standard protocol (AAC, five biopsies) identified more cases of AG/IM than the restricted one (AC, four biopsies) (79 vs 56 cases). The estimated number of patients needed to test (biopsy) in order to identify one patient with AG/IM in our study population was seven.
H pylori were found in a total of 94 of all 213 patients (55.9% positive). Sixty-four subjects were positive in culture (30.3%); in 58 patients, H pylori bacteria were seen on histology (27.2%), and the rapid urease test showed a positive result in 48 cases (24%), see table 1. IgG antibodies against H pylori were detected in 82 patients (40.6%); of which, 19 tested negative for active infection. Positive H pylori status was correlated with the presence of chronic gastritis and AG/IM. The proportion of H pylori-positive cases in the disease groups is presented in figure 1.
Parameters of inflammation in antrum versus angulus
The average scores of the analysed parameters of inflammation at all biopsy sites obtained according to the updated Sydney system are shown in table 3. None of the parameters differed significantly at the two biopsy sites representing the antral mucosal compartment (antrum vs angulus). Only the grade of chronicity differed significantly when compared with the corpus (oxyntic mucosa) (p=0.026, ANOVA).
The absolute number of patients with preneoplastic conditions of any grade also did not vary significantly at the three biopsy sites as shown in table 4. The most prevalent form of premalignant gastric condition found at the angulus biopsy site was mild atrophy.
The angulus biopsy accounted for 17 patients (7.9%) and 6 patients (2.8%) to be diagnosed with AG and IM, respectively, as a singular manifestation site of the preneoplastic condition. These cases, which would have been missed if a biopsy from the angulus had not been taken, showed only mild-to-moderate preneoplastic changes. Furthermore, in four cases with AG and four cases with IM, the scores were higher in the angulus than in the antrum. The discrepancies of AG and IM scores between antrum and angulus are shown in figure 2.
Risk stratification (OLGA/OLGIM) and biopsy protocol
Patients’ distribution in OLGA and OLGIM stages is demonstrated in figure 3. We re-evaluated the stages in both systems, leaving out the findings from the angulus biopsy. The majority of patients scored 0 in OLGA and OLGIM (150 and 168, respectively). We observed a significant decrease in the OLGA stages when the restricted AC biopsy protocol was applied (means 0.535±0.9 vs 0.404±0.9; p<0.001, t test). OLGIM stages also varied significantly depending on the biopsy protocol (0.333±0.757 vs 0.258±0.669; p=0.001, t test) (table 5). However, the absolute number of patients diagnosed with high-risk OLGA stages (III+IV) did not change significantly depending on the biopsy protocol (AAC vs AC, 15 vs 13, respectively). Same applies for OLGIM with seven versus four patients in high-risk gastritis stages.
Interestingly, OLGA generated significantly more moderate-to-severe stages than OLGIM according to the standard biopsy protocol (OLGA ≥II vs OLGIM ≥II n=34 vs 17; p=0.016, Fisher's exact test).
Premalignant conditions of gastric mucosa have a high prevalence in our population (79/213, 37%) when compared with the prevalence recently reported from other countries in Europe.1 ,13 However, severe extensive AG or IM with substantially increased risk for GC was found in a small subset of patients (18/213, 8.5%). This is in correspondence with epidemiological data from Germany,14 where the serologically estimated prevalence of atrophy (defined as serum pepsinogen I level <70 ng/mL and pepsinogen I:II ratio <3) was 6% in a cohort of 9444 patients. Based on a follow-up period of 5 years, the annual incidence for AG15 has been reported to be 1.1%. The histological prevalence of AG and IM in our study varies around 10% (37% vs 27%) depending on if the angulus biopsy was considered or not.
Former studies indicated ‘maximal degrees of atrophy and intestinal metaplasia in the region of the incisura angularis’,16 ,17 and accordingly, the angulus biopsy had been integrated in the biopsy protocol of the updated Sydney system. The angulus region as the elective site for the development of premalignant conditions has been confirmed in several studies.18–23 However, the clinical benefit by an additional angulus biopsy for the diagnosis of premalignant gastric conditions has been questioned.24–28 In fact, we detected mostly mild atrophy (25/79, 32%) at the angulus, and the clinical relevance of mild atrophy may indeed be low. But, it remains unquestionable that taking biopsies at the incisura angularis with additional 8% of atrophy and 3% of IM diagnosed is superior as compared with multiple random biopsies.
It has been shown that increasing the number of non-targeted biopsies (up to 12 biopsies) raises the diagnostic yield for AG and IM by approximately 5% per two additional biopsies.18 ,19 ,26 Our data suggest that the diagnostic benefit of the biopsy from incisura angularis is rather due to the effect of an additional biopsy than of a more informative biopsy as reported by other authors.21 Neither the mean scores for parameters of inflammation nor the absolute number of patients with AG and IM of any grade differed significantly at the angulus site compared with antrum or corpus. On the other hand, the angulus biopsy in our study seems particularly relevant for the detection of mild gastric atrophy in the general patient population undergoing upper gastrointestinal endoscopy. To ultimately determine the diagnostic advantage of an angulus biopsy, a prospective randomised study comparing three antrum biopsies versus two antrum and one angulus in addition to the corpus biopsies would be necessary. To our knowledge, such study has not been conducted so far.
In cases with severe AG or IM in the corpus, even mild atrophic or metaplastic changes of the antral mucosa would define a high-risk gastritis stage according to both systems for GC risk assessment. OLGA and OLGIM stages (means) decreased significantly when the angulus biopsy was not taken into account. This is of uncertain clinical significance as the absolute number of patients in high-risk OLGA stages ≥III (high risk), which would be selected for follow-up, did not change significantly depending on the biopsy protocol. However, two high-risk OLGA and three high-risk OLGIM cases would have been misdiagnosed as low risk, and not offered surveillance. This finding, although not statistically significant, demonstrates a role of the incisura angularis biopsy in the management of patients with high-risk preneoplastic conditions. Interestingly, the OLGA system generated significantly more moderate-to-high-risk cases (stage ≥II) than OLGIM. This is in line with the results of a large comparative study by Rugge et al29 of OLGA versus OLGIM, where 6% of high-risk OLGA stages (III+IV) were downstaged to low risk when using OLGIM (I+II). Currently, there is no clear recommendation, which system should be favoured for staging and follow-up of preneoplastic conditions in the stomach, and the choice will depend on local factors that include the experience of pathologists and the prevalence of atrophy and IM in the population. A biopsy from incisura angularis is currently required in both biopsy protocols.
Concerning H pylori status, culture performed best of the three tests for active infection applied in the study even in cases with pronounced premalignant changes. In six cases, H pylori could only be cultured from the corpus (data not shown) as reported previously in cases with extensive atrophy or IM.30 We consider serology useful as recommended in the Maastricht IV guidelines31 because a large number of patients are not PPI naive when scheduled for endoscopic examination. Mucosal atrophy may additionally hinder the detection of H pylori infection due to the reduction of colonisation density. Furthermore, preneoplastic conditions could represent the long-term effect of a previous infection. In our study, 19 cases (9%) with H pylori were only detected by use of serology.
The recent recommendation for endoscopic follow-up of subjects with extensive and severe preneoplastic conditions implicates considerable resources and risks, which go along with numerous additional upper endoscopies per year even in Europe where the prevalence of high-risk preneoplastic conditions is relatively low. Some authors reported a better diagnostic yield through targeted biopsies32 ,33 next to the currently indispensable routine non-targeted biopsies.34 Surveillance results will be difficult to interpret given the patchy distribution of preneoplastic conditions and sampling errors, variable interobserver agreement and moderate intrabiopsy agreement.10 ,35 In the guidelines, it was surprisingly agreed on a minimum of four biopsies (two antrum and two corpus). Notably, only 20% of the representatives of national societies stated that the recommended biopsy protocol is widely applicable in routine practice in their countries.11 Inconsistent biopsy protocols will certainly further complicate the analysis and comparison of surveillance data.
In conclusion, the angulus biopsy is relevant for optimising the histopathological assessment of premalignant gastric conditions. However, the diagnostic yield of the additional angulus biopsy did not reach significance level in GC risk stratification; its clinical usefulness in surveillance endoscopies remains controversial.
Take home messages
The diagnostic benefit of the biopsy from incisura angularis is rather due to the effect of an additional biopsy than of a more informative biopsy.
The angulus biopsy seems particularly relevant for the detection of mild gastric atrophy.
Operative link on gastritis assessment and operative link on gastritis assessment using intestinal metaplasia staging were negatively influenced by a biopsy protocol restricted to antrum and corpus.
We thank the endoscopy and laboratory team for their contribution to the study.
Abstract in German
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
- Abstract in German - Online abstract
Handling editor Cheok Soon Lee
Contributors MV, TW and MS developed the work concept. MV wrote the manuscript. DJ performed most of the histopathological finding. FWR provided the statistical approach and calculations. CL managed the laboratory part of the project. PM kindly supervised all stages of the project, and edited the manuscript.
Funding This work was supported in part by a grant from the BMBF (BMBF-0315905D) in the frame of ERA-Net PathoGenoMics.
Competing interests None declared.
Ethics approval Ethics Committee of the Otto-von-Guericke University Magdeburg.
Provenance and peer review Not commissioned; externally peer reviewed.