Intestinal and diffuse types of gastric cancer: secular trends in Sweden since 1951

CDX2 Expression in Gastric Carcinoma: A Clinicopathological Study

Background: Gastric cancer accounts for 7.8% of cancers worldwide and adenocarcinoma is the commonest histological type. Both gastric and intestinal phenotypic cell markers are expressed in gastric carcinomas. CDX2 is an intestinal transcription factor, which can be demonstrated in intestinal metaplasia and gastric carcinomas of the intestinal type. Unlike colorectal carcinomas, the role of CDX2 in gastric carcinomas as a prognostic variable is yet to be established. Ki-67 is a transcription factor expressed in the growth and synthetic phases of the cell cycle. Aims and Objectives: The aims of the study were to analyze CDX2 expression and Ki-67 labeling index in different histological types of gastric carcinomas and their relationship with the patients' clinicopathological parameters. Materials and Methods: A total of 50 gastric carcinoma cases were evaluated histologically and phenotypically, along with assessment of CDX2 expression and Ki-67 labeling index. Gastric carcinomas were grouped into intestinal and diffuse types, according to Lauren classification. A semiquantitative microscopic evaluation of CDX2 expression and Ki-67 labeling index was performed and correlated with the patients' clinicopathological parameters. Results: Increased CDX2 expression correlated with higher proportion of intestinal type gastric carcinomas and a lower proportion of lymph node metastasis, lymphovascular and perineural invasion. On the other hand, high Ki-67 labeling index was found in high grade tumors with lymphovascular invasion. Conclusions: The results of our study suggest that CDX2 might be a useful marker in predicting the prognosis of patients with gastric carcinoma. Accordingly, Ki-67 index seems to be useful in identifying a group of patients with aggressive tumors.

Clinical epidemiology of gastric cancer

Gastric cancer is the second leading cause of cancer-related mortality and the fourth most common cancer globally. There are, however, distinct differences in incidence rates in different geographic regions. While the incidence rate of gastric cancer has been falling, that of gastric cardia cancers is reportedly on the rise in some regions. Helicobacter pylori (H. pylori) infection is a major risk factor of non-cardia gastric cancer, and data has emerged concerning the role of H. pylori eradication for primary prevention of gastric cancer. Dietary, lifestyle and metabolic factors have also been implicated. Although addressing these other factors may contribute to health, the actual impact in terms of cancer prevention is unclear. Once irreversible histological changes have occurred, endoscopic surveillance would be necessary. A molecular classification system offers hope for molecularly tailored, personalised therapies for gastric cancer, which may improve the prognosis for patients.

Exploring the cost-effectiveness of Helicobacter pylori screening to prevent gastric cancer in China in anticipation of clinical trial results

Gastric cancer is the second leading cause of cancer-related deaths worldwide. Treatment for Helicobacter pylori infection, the leading causal risk factor, can reduce disease progression, but the long-term impact on cancer incidence is uncertain. Using the best available data, we estimated the potential health benefits and economic consequences associated with H. pylori screening in a high-risk region of China. An empirically calibrated model of gastric cancer was used to project reduction in lifetime cancer risk, life-expectancy and costs associated with (i) single lifetime screening (age 20, 30 or 40); (ii) single lifetime screening followed by rescreening individuals with negative results and (iii) universal treatment for H. pylori (age 20, 30 or 40). Data were from the published literature and national and international databases. Screening and treatment for H. pylori at age 20 reduced the mean lifetime cancer risk by 14.5% (men) to 26.6% (women) and cost less than $1,500 per year of life saved (YLS) compared to no screening. Rescreening individuals with negative results and targeting older ages was less cost-effective. Universal treatment prevented an additional 1.5% to 2.3% of risk reduction, but incremental cost-effectiveness ratios exceeded $2,500 per YLS. Screening young adults for H. pylori could prevent one in every 4 to 6 cases of gastric cancer in China and would be considered cost-effective using the GDP per capita threshold. These results illustrate the potential promise of a gastric cancer screening program and provide rationale for urgent clinical studies to move the prevention agenda forward.

Development of an empirically calibrated model of gastric cancer in two high-risk countries

Although epidemiologic studies have established the relationship between Helicobacter pylori and gastric cancer and promising results that H. pylori treatment can reduce cancer incidence among individuals without preexisting precancerous lesions, there is no consensus on whether screening for H. pylori should be conducted. Our objective was to synthesize the available data to develop and empirically calibrate a mathematical model of gastric cancer and H. pylori in China and Colombia that could be used to provide qualitative insight into the benefits and cost-effectiveness of primary and secondary gastric cancer prevention strategies. The model represents the natural history of noncardia intestinal type gastric adenocarcinomas as a sequence of transitions among health states (e.g., normal gastric mucosa, chronic nonatrophic gastritis, gastric atrophy, intestinal metaplasia, dysplasia, and gastric cancer) stratified by H. pylori status. Initial plausible ranges for each parameter were established using data from published literature. A likelihood-based empirical calibration approach was used to identify multiple good-fitting parameter sets that were consistent with epidemiologic data. We then used these parameter sets to estimate a range of likely outcomes associated with H. pylori screening. This modeling approach allows for parameter uncertainty surrounding the natural history of H. pylori and gastric cancer to be reflected in the results of comparative analyses of different gastric cancer prevention strategies. As better data become available, the model can be refined and recalibrated, and, as such, be used as an iterative tool to assess the likely health and economic outcomes associated with gastric cancer prevention strategies.

Oestrogen and the enigmatic male predominance of gastric cancer

Gastric cancer is the second most common cause of cancer death worldwide, and annually it causes over 150,000 deaths in Europe and 700,000 deaths globally. The incidence of gastric cancer shows an enigmatic male dominance with a male-to-female ratio of about 2:1. This sex ratio cannot be entirely attributed to the differences in the prevalence of known risk factors between the sexes. This review focuses on the potential role of oestrogen in explaining the male predominance in gastric cancer. Some data argue in favour of sex hormonal influence. Women with a longer fertility life and those on hormone replacement therapy seem to have a decreased risk of gastric cancer, and men who have been treated with oestrogen for prostate cancer have a decreased risk. Use of tamoxifen in women seems to increase their risk of gastric cancer. Animal studies indicate that oestrogen may offer protection against the development of this cancer as for example ovariectomised mice are at an increased risk, whilst administration of female sex hormones decreases the incidence of gastric cancer. Oestrogen may exert its effect by acting on oestrogen receptors (ERs). Both ERalpha, ERbeta and the latest discovered ERbetacx have been identified in gastric tissue. The biological means behind this is not yet clear but various mechanisms have been suggested. There are indications that oestrogen may lead to an increased expression of trefoil factor proteins, which protect mucous epithelia or inhibit the expression of c-erb-2 oncogene.

Helicobacter pylori: resurrection of the cancer link

Helicobacter pylori is one of the most common pathogenic bacterial infections, colonizing an estimated half of all humans. In a subset of individuals, the infection leads to serious gastroduodenal disease such as peptic ulcers and gastric adenocarcinoma. The factors contributing to skewing this, in most cases benign, relationship into disease development are largely unknown. However, factors emanating from the bacterium, host and the environment have been shown to affect the risk for disease, although no factor can be singled out to be most important. The known factors are associated with affecting the risk of disease, and are not absolute. Virulence of H. pylori is affected by the existence and regulation of certain genes present in the bacterial population in a stomach. The effects of H. pylori on gastric cancer development have been challenged and the risk associated with infection with virulent (i.e. Cag PAI positive) H. pylori has likely been underestimated.

Cigarette smoking, alcohol consumption and subsequent gastric cancer risk by subsite and histologic type

The effect of cigarette smoking or alcohol consumption on the risk of gastric cancer has not been clarified. We investigated this relationship, considering the anatomic subsite and histologic type of gastric cancer. A total of 19,657 men (aged 40-59 years at baseline), who responded to the baseline questionnaire and reported no serious illness at that time, were followed for 10 years, from January 1990 to December 1999. Gastric cancer was confirmed histologically in 293 men. Smoking was associated with an increased risk of the differentiated type of distal gastric cancer; compared to the group who never smoked, the adjusted rate ratios (RRs) of gastric cancer for past and current smokers were 2.0 (95% CI 1.1-3.7) and 2.1 (95% CI 1.2-3.6), respectively. No association was observed between cigarette smoking and risk of the undifferentiated type of distal gastric cancer except for a suggestive association with cardia cancer. For alcohol consumption, elevated risk was suggested only for cardia cancer of all histologic types, though the relationship failed to reach significance. Among those who drank alcohol at least once per week, RRs for ethanol intake of 2.7-161.0, 162.0-322.0 and 322.5+ g/week compared to those who drank 0-3 times/month were 2.5 (95% CI 0.7-9.5), 3.3 (0.9-11.6) and 3.0 (0.8-11.1), respectively (p(trend) = 0.66). In conclusion, our results confirm that smoking is related to gastric cancer of the differentiated type. Further studies with more cases are needed to detect a positive association between cigarette smoking or alcohol consumption and cardia cancer.

General features of gastric carcinomas and comparison of HSP70 and NK cell immunoreactivity with prognostic factors

During the period of 1996-1998 ninety-four gastrectomy specimens with gastric carcinoma referred to Erciyes University, Medical Faculty, Department of Pathology, were examined histopathologically, histochemically and immunohistochemically. General characteristics of gastric carcinomas and prognostic factors were studied. According the Lauren classification, of the 94 cases of gastric carcinomas, 56 were intestinal type, 21 were diffuse type and 17 were mixed type carcinoma. The association rates of Helicobacter pylori, chronic atrophic gastritis and intestinal metaplasia with gastric carcinomas were high. There was strong immunorectivity with HSP70 in 62,5% of the intestinal type carcinomas. This ratios were lower in diffuse and mixed type carcinomas (p<0.05). The more tumor size and invasion depth increased, the more HSP70 immunoreactivity was obtained (p<0.05). HSP70 immunorectivity was considerably higher in the patients having lymph node metastasis and vascular invasion (p<0.05). It was found that the NK cell number was low in the tumor but higher around the tumor in early gastric carcinomas, compared with advanced carcinomas (p>0.05). In the tumors larger than 10 cm with vascular invasion, NK cell number was lower around the tumor (p>0.05). Defining prognostic factors of gastric carcinomas is of importance to clinicians. It is thought that HSP70 immunoreactivity, besides invasion depth, lymph node metastasis, vascular invasion, tumor size and inflammatory reaction against the tumor, is important in prognosis and associated with advanced stage.

Decreasing incidence of both major histologic subtypes of gastric adenocarcinoma--a population-based study in Sweden

While the overall incidence of gastric cancer has fallen, presumably to a large extent in parallel with Helicobacter pylori infection, the occurrence of the diffuse histologic type is thought to have remained more stable, questioning the aetiologic role of H. pylori. We have analysed the incidence of the intestinal and diffuse types separately, while considering subsite (cardia/non-cardia). With an extensive prospective effort we identified all incident cases of gastric adenocarcinoma (n = 1337) in a well-defined Swedish population (1.3 million) 1989-1994. Tumours were uniformly classified histologically and topographically. Subgroup-specific incidence rates were computed and modelled using multivariate logistic regression. Site-specific trends were clearly discrepant. The overall incidence of adenocarcinoma distal to the gastric cardia declined by 9% (95% confidence interval 6-12%) per year, while cardia cancer remained stable. Thus, the feared rise in cardia cancer could not be confirmed despite clear site-specific trend discrepancies. The intestinal type predominated, especially in high-risk areas, while diffuse tumours prevailed among young patients and women. Both main histologic types of gastric adenocarcinoma declined markedly, at similar rapidity, and with no significant trend differences between the intestinal and diffuse types, even after multivariate adjustments. Our results are consistent with an aetiologic role of environmental factors including H. pylori also for diffuse-type gastric cancers.

Changing pattern of histological type, location, stage and outcome of surgical treatment of gastric carcinoma

BACKGROUND

There are indications that some features of gastric carcinoma are changing, with a possible impact on prognosis. The aim of this study was to examine any changes in type, location, stage, resection rate, postoperative mortality rate or prognosis for patients with gastric carcinoma in a well defined population.

METHODS

During 1974-1991, 1161 new cases of gastric adenocarcinoma were diagnosed in Ostergötland County, Sweden. Tumour location, Laurén histological type, tumour node metastasis (TNM) stage, radicality of tumour resection and postoperative complications were recorded after histological re-evaluation of tissue specimens and examination of all patient records. Dates of death were obtained from the Swedish Central Bureau of Statistics. Time trends were studied by comparing the intervals 1974-1982 (period 1) and 1983-1991 (period 2).

RESULTS

The proportion of diffuse type of adenocarcinoma increased (from 27 to 35 per cent), while that of mixed type decreased (from 16 to 9 per cent) and that of intestinal type was unchanged. The proportion of tumours located in the proximal two-thirds of the stomach increased (from 32 to 42 per cent) and the proportion of patients with tumours in TNM stage IV decreased (from 32 to 25 per cent). Overall tumour resection rates were unchanged, although the proportion of radical total gastrectomies increased (from 36 to 50 per cent). Excluding tumours of the cardia or gastric remnant after previous ulcer surgery, the 5-year relative survival rate after radical resection increased from 25 to 36 per cent and the postoperative mortality rate decreased for both radical (from 11 to 4 per cent) and palliative (from 18 to 6 per cent) resection.

CONCLUSION

The patterns of tumour histology, location and stage of gastric carcinoma have changed in the authors' region. These changes were paralleled by a significant improvement in survival and postoperative mortality rates.

Gastric cancer in the European Union (1968-1992): mortality trends and cohort effect

PURPOSE

To analyze patterns and trends in gastric cancer mortality in the European Union (EU) over the period 1968-1992, paying special attention to changes associated with birth cohort.

METHODS

Poisson log-linear models were used to quantify geographic differences and relative annual changes. To assess trends associated with birth cohort, invariant parameters from sex-specific age-period-chohort models (net drift and curvature), for each country, were used to choose a restricted slope range for cohort effect.

RESULTS

Gastric cancer mortality declined throughout the EU. The male-to-female ratio stood at around 2 in all countries, yet showed a slight rise over time. Portugal reported the highest age-adjusted rates for men and women (45.63 and 23.31 per 100,000 person-years, respectively). The rate ratio between two extreme countries (Portugal/Denmark) exceeded 3. Quantitative intercountry differences were found in trend slopes, with a decrease of 5% per annum in Finland. Risk of dying associated with birth cohort decreased over successive generations. Small local rises in risk, in almost all countries among generations born around the 1940s, support the importance of diet early in life in the etiology of gastric cancer.

CONCLUSIONS

Despite the substantial decline in gastric cancer mortality witnessed in the EU, stress must be accounted for the wide differences among countries and the smaller decline in the youngest generations, particularly among women. This latter finding suggests a possible stabilization or even a rise in the rates in future, rendering it important for these trends to be monitored over the next few years.

Can endoscopic biopsy specimens be used for reliable Laurén classification of gastric cancer?

BACKGROUND

The aim of this study was to ascertain whether routine endoscopic biopsy specimens are of sufficient quality and representative enough to enable reliable classification of histologic type, grade of differentiation, and frequency of signet ring cells.

METHODS

As part of a population-based etiologic study of gastric cancer in Sweden, the histologic slides of 687 incident cases were independently reviewed by one pathologist. In 305 cases both biopsy and surgical specimens were available for assessment of sensitivity and specificity of diagnoses on the basis of biopsy specimens, with the classification based on surgical specimens as the gold standard.

RESULTS

The sensitivity and specificity of the diagnoses on the basis of biopsy specimens was 86% and 82%, respectively, for detecting the intestinal type, and 87% and 90%, respectively, for the diffuse type of gastric cancer. The percentage agreement between biopsy and surgical specimens with regard to grade of differentiation was 71%.

CONCLUSIONS

This study shows that misclassification of Laurén type due to random intraobserver variation needs to be taken into account in epidemiologic studies. The degree of misclassification appears to be of similar magnitude regardless of the source material.

Sex as a prognostic factor in gastric cancer

The aim of this study was to assess whether survival of gastric cancer patients differed between males and females. Although it is well known that the incidence of gastric cancer is higher for men than for women, the existence of a sex-specific prognosis has seldom been addressed. Studies based on population registries have not assessed the role of stage and histology. Cases of histologically confirmed gastric carcinoma were obtained from three Spanish hospitals in Soria (n = 405), Barcelona (n = 249) and Mataró (n = 197). Differences in possible confounders were tested between men and women and survival analyses were performed separately by hospital. Cox's proportional hazards models were used to account for age, tumour stage, histology and tumour sub-location. Only in Mataró was a significant difference in the stage distribution observed between women and men, with a lower proportion of local stage tumours among women (P = 0.047). No statistically significant differences of histological type between men and women were observed in any of the centres. After adjusting for tumour stage and age, women were observed to have significantly better survival in Barcelona (female to male hazard ratio (HR) = 0.578, P < 0.001); this effect was marginal in Soria (HR = 0.788, P = 0.092) and non-significant in Matar-o (HR = 0.895, P = 0.54). Age-adjusted hazard ratios were calculated within each tumour stage. For Barcelona, the effect of better prognosis among women was most marked at local stage (HR = 0.320, P = 0.013), and in Soria at the regional stage (HR = 0.426, P = 0.002). Although in Mataró all HRs were below unity, none were statistically significant. Little effect was observed at the disseminated stage. The other covariables exerted no influence. Women appear to have a better prognosis than men, and the difference could be tumour stage dependent. Confirmation of these findings would give a valuable insight into gastric cancer growth and ultimately be of use in planning treatment.