Gastric cancer in Scotland: changing epidemiology, unchanging workload

Gastric cancer

Gastric cancer is one of the most common cancers and one of the most frequent causes of cancer-related deaths. The incidence, diagnostic studies, and therapeutic options have undergone important changes in the last decades, but the prognosis for gastric cancer patients remains poor, especially in more advanced stages. Surgery is the mainstay of treatment of this disease, even if it is associated with a high rate of locoregional and distant recurrence. There is ongoing debate regarding the role of adjuvant treatment In advanced disease, palliation of symptoms, rather than cure, is the primary goal of patient management. Several combination therapies have been developed and have been examined in phase III trials; however, in most cases, they have failed to demonstrate a survival advantage over the reference arm. This review summarizes the most important recommendations for the management of patients with gastric cancer.

Trends in oesophago-gastric surgery in Scotland

BACKGROUND

The last twenty years have seen significant changes in both the incidence and treatment of gastro-oesophageal disorders as well as a process of subspecialisation in general surgery. The aim of this study is to identify the changes in gastro-oesophageal surgery in Scotland during this period.

METHODS

A retrospective analysis of three years of data, taken over a 20-year period (1977, 1987 and 1997) obtained from the Information and Statistics Division of the Scottish National Health Service, examining the number of patients with oesophageal cancer, gastric cancer and gastro-oesophageal reflux disease (GORD) treated by general and thoracic surgeons.

RESULTS

There was a significant increase (p=0.001, chi2) in the number of patients with oesophageal cancer (2.52-fold) and gastric cancer (1.4-fold) treated by general compared with thoracic surgeons. Since 1977, the overall operability for oesophageal cancer has remained unchanged, while a significant decrease in the overall operability of gastric cancer was noted (p<0.001, chi2). There was a 3-fold increase in the incidence of GORD with a significant increase (p<0.001, chi2) of those treated surgically. Since 1977, there has also been a significant shift of workload from thoracic to general surgical units.

CONCLUSIONS

Scotland has seen a consistent increase in the surgical workload generated by gastro-oesophageal malignancies over the last three decades without any improvement in the operability rate. Surgically treated GORD has also increased, probably due to the introduction of minimally invasive techniques. These trends have implications on healthcare planning, resource allocation and surgical training. Appropriate resources and trainees should follow the patients to those units carrying out this activity. Further centralisation of these services is likely to follow.

Site distribution of oesophagogastric cancer

AIMS

It has been suggested that adenocarcinomas of the lower oesophagus and gastric cardia should be reclassified as oesophagogastric junction (OGJ) cancers. This study aimed to define the frequency of OGJ cancers in a geographically defined population of 4.3 million people.

METHODS

All cases of oesophageal and gastric cancer occurring in 1993 were identified by the North Western Regional Cancer Registry. A total of 1192 hospital case notes were reviewed and a study group of 1067 patients was defined. Tumour involvement was documented at individual subsites in the oesophagus and stomach, allowing for tumour presence in more than one oesophageal/gastric subsite.

RESULTS

There were 627 tumours in men and 440 in women. The tumour was confined to the oesophagus in 281 (26.3%) cases and to the stomach in 454 (42.6%) cases. The tumour encroached upon or crossed the OGJ in 332 (31.1%) cases. Overall, tumours involved the cardia, OGJ, or lower oesophagus in 633 (59.3%) cases; in 179 (18.5%) cases the tumour involved the lower oesophagus but not the OGJ, and in another 122 (11.4%) cases the cardia was involved but not the OGJ.

CONCLUSIONS

Oesophagogastric cancers in this population predominantly involve the OGJ, lower oesophagus, and/or cardia.

c-erbB2 and p53 expression are not associated with stage progression of gastric cancer in Britain or Japan

The results of surgical treatment for gastric cancer are apparently better in Japan than in Western countries. It has been proposed that this is because of a biological difference between the tumours in Japan and in the West. We have previously reported very similar frequencies of positive immunohistochemical staining for the c-erbB2 oncogene and mutant p53 proteins in British and Japanese gastric cancers, findings which do not seem to support the 'biological difference' hypothesis. We realized that these studies did not rule out differences in the mechanism of cancer progression which might show themselves by a different association between p53 and c-erbB2 expression and stage in the two populations. We therefore re-analysed our data to look for differences in the frequency of p53 and c-erbB2 expression in the British and Japanese populations. Comparison of fixed tissue from 88 British and 89 Japanese tumours showed no significant association of c-erbB2 or p53 with stage progression in either population. Logistic regression showed no difference between the two populations in the relationship between stage and oncogene expression. These results do not support the idea of biologically different cancers in Japan and Britain. Other possible explanations for the difference in results such as the stage migration effect, better efficacy of Japanese-style surgery, or a difference in the host resistance to cancer in the two countries should be considered.

The influence of age on the surgical management of carcinoma of the stomach

The medical records of 31,808 patients with gastric cancer registered with the West-Midlands Cancer Registry between 1957-1981 were reviewed to determine the influence of age on presentation, stage assessment, management, survival and mortality rates. When analysed by stage, and excluding post-operative deaths, survival was similar in all age groups. This study confirms stage of disease to be the single most important prognostic factor. The inverse relationship between laparotomy and age implies inadequate assessment of stage in the elderly. The poor prognosis in unresected cases suggests that increased precise staging by laparotomy or laparoscopy will have minimal adverse effects. On the other hand this may result in increased resections and survival.

Oesophageal and gastric cancer in Scotland 1960-90

In Scotland over the last 31 years the incidence of gastric cancer has significantly declined by 0.6% per annum in males and 1.1% in females. In contrast, for oesophageal cancer, incidence rates have risen significantly by 3.0% and 2.0% per annum in males and females respectively. Increasing incidence of both adenocarcinomas and squamous carcinomas of the oesophagus in men and squamous and recently adenocarcinomas in women has been observed. This cannot be entirely accounted for by a growth in the proportion of histologically verified (HV) tumours over time. The incidence of adenocarcinoma of the stomach increased over the study period, most likely because of increasing proportions of HV tumours and improved diagnostic precision. Areas with high levels of deprivation in Scotland are strongly associated with high rates of oesophageal cancer in men, and of gastric cancer in both men and women. All these observations are discussed in the context of current knowledge of risk factors for these diseases.

Effects of acid suppression on microbial flora of upper gut

Decreased acid secretion, due to therapy or disease, predisposes to increased bacterial counts in gastric juice. As bacterial numbers increase, the number of nitrate-reducing strains and the concentration of luminal nitrite usually also increase. However, there is controversy (mainly because of assay problems) about whether decreased acid increases generation of N-nitroso compounds: these may be produced by acid or by bacterial catalysis, and the relative contributions of each are still uncertain. Other potentially important factors include ascorbate secretion (can prevent nitrite conversion to nitroso compounds) and the particular spectrum of nitroso compounds produced. Nitrosation of several histamine H2-receptor antagonists has been demonstrated experimentally, but under conditions that are very unlikely to be encountered clinically. Some acid suppressant therapies have been claimed to aid eradication of Helicobacter pylori, but more work is needed to evaluate this. If ulcer treatment regimens do not also address eradication of H. pylori (when present), gastritis will progress, and the recently documented association between H. pylori and gastric carcinoma needs to be considered. Enteric flora probably also increase if acid secretion is markedly reduced: this does not appear to have nutritional consequences but probably reduces the resistance to occasional infections, of which cholera is the best documented.

Improving survival in gastric cancer: review of 5-year survival rates in English language publications from 1970

In this review of English language publications from 1970, 5-year survival rates after surgery for gastric cancer have been analysed. While the proportion of patients coming to operation has fallen from 92 per cent before 1970 to 71 per cent by 1990, the proportion of operated patients undergoing resection has increased from 37 per cent before 1970 to 48 per cent before 1990. This change suggests improved preoperative staging leading to better patient selection for operation. The 5-year survival rate following all resections has increased significantly from 20.7 per cent before 1970 to 28.4 per cent before 1990, an increase of 7.7 per cent (95 per cent confidence interval 7.1-8.3 per cent). The 5-year survival rate following curative or radical resection has risen from 37.6 to 55.4 per cent over the same period, an increase of 17.8 per cent (95 per cent confidence interval 17.1-18.5 per cent). It is likely that this improvement has contributed to the decrease in the mortality rate from gastric cancer. Comparison of Japanese series with others suggests that diagnosis and treatment of the disease at an earlier stage will result in an even greater increase in 5-year survival rates outside Japan. Of the papers studied, 56 per cent were excluded from analysis, the majority because the data provided about 5-year survival rates were insufficient or the survival calculations inappropriate. Results of survival after operations for gastric cancer should be calculated and presented in a standardized manner.

Improving survival in gastric cancer: review of operative mortality in English language publications from 1970

In this review of English language publications from 1970, operative mortality following surgery for gastric cancer has been analysed. Operative mortality has declined in series reporting operations in successive decades to 1970, 1980 and 1990. Series reporting patients having surgery for gastric cancer in the decade to 1990 show a mean operative mortality rate of 7.8 per cent (median 4.6 per cent). This improvement may have contributed to the declining mortality rates for gastric cancer in the face of unchanging surgical workload. Results of operations for gastric cancer should be reported in a standard manner.

Improving results in the treatment of gastric cancer: an 11-year audit

Of 280 patients presenting to one hospital with gastric cancer between 1975 and 1985, 97 (35 per cent) did not undergo surgery and 29 per cent (54 out of 183) of those who did had no resection performed. The 30-day operative mortality rate in the study period was 15 per cent (28 out of 183) but in the subsequent 4-year period this fell to 7 per cent (5 out of 69). The survival rate correlated significantly with depth of invasion but not with tumour site or degree of differentiation. The incidence of early gastric cancer in this series was 5 per cent but the 5-year survival rate in this group was 52 per cent suggesting that the true incidence might be even lower. The overall 5-year survival rate in our area 20 years ago was only 5.2 per cent but in this series it was 11 per cent overall and 24 per cent after resection, and with actuarial correction 15 per cent overall and 28 per cent after resection. The continuing improvement in operative mortality rates and in 5-year survival rates gives grounds for optimism, but the disease must be diagnosed earlier if this improvement in outlook is to continue.