Gastric cancer is the second most frequent cause of death from cancer worldwide, with a mortality rate (adjusted for the world population, AWP) of 15.62 per 100,000 inhabitants, and is more frequent among men.1 However, during the last ten years the characteristics of and attitudes toward this type of cancer have changed. This shift has come about thanks to a number of factors, which include: a) a decrease in the incidence of and mortality from gastric cancer; b) the identification of Helicobacter pylori and other environmental agents as causal factors; c) an increase in the incidence of cancer of the gastric cardia (and a decrease in cancer of the distal stomach, antrum and corpus); d) advances in the knowledge of the molecular biology of the tumor; e) a new TNM classification which makes it possible to estimate prognosis more accurately, along with awareness of the importance of lymph node involvement in prognosis; f) new treatment modalities, and g) in some countries such as Japan where the incidence if gastric cancer is high, the use of population screening.2
Spain, together with other southern European countries (i.e., Portugal and Italy), as well as Austria and Germany, ranks among the countries in Europe with the highest incidence (7.57 per 100,000 inhabitants, AWP) and mortality rates (5.37 per 100,000 inhabitants, AWP). These figures are higher than the European averages of 6.67 and 5.13 per 100,000 (both AWP), respectively.1
Mortality from gastric cancer, as shown in the study published in this issue by Ruiz Ramos et al,3 particularly mortality in Andalusia, has decreased in recent decades. In Spain this decrease began at the end of the 1960s, i.e., somewhat later than in other countries. By 1974 lung cancer had replaced gastric cancer as the leading cause of death from all types of cancer.
The geographic distribution of gastric cancer in Spain, as shown in the study by Ruiz Ramos,3 and based on an analysis of mortality from gastric cancer in Spain in 1996, reveals that rates vary from one part of the country to another. Within Spain there is a gradient from inland areas toward the coast, with highest rates recorded for the autonomous community of Castilla and León (AWP rate 22.42 per 100,000 in men in Burgos province) and lowest rates on the Mediterranean coast (AWP rate 8.13 per 100,000 men in Almería province). The reasons for this decrease in the incidence of gastric cancer are not entirely known, but changes in dietary habits have been clearly implicated. The higher consumption of fresh fruits and vegetables along with the lower consumption of foods preserved by salting, pickling or smoking, together with improvements in the preservation of fresh foods, partly explain the decrease.4 The distribution of these dietary factors, along with smoking and drinking patterns, appear to be involved in the geographical differences in the incidence of gastric cancer in Spain. Some authors have also suggested that lower socioeconomic level, latitude and altitude are factors that might account for part of these differences.
Other factors that should be taken into account in the distribution and risk of gastric cancer are the prevalence of H. pylori infection and the many partial gastrectomies done to treat ulcers more than 10 years ago. Gastric cancer occurs in only a small percentage of patients with H. pylori infection, hence generalized eradication with antibiotic treatment is not justified in view of its cost and the risk of resistance.4 Nonetheless, eradication of the infection is recommended for patients who have had a partial gastrectomy.
Despite the marked decrease in the incidence of and mortality from gastric cancer, in most patients the tumor is diagnosed when it has reached an advanced stage and is inoperable. In western countries the tumor is advanced and the prognosis is poor in more than 80% of the patients at the time of diagnosis.5 Against this background treatment can only be palliative, except in those cases when chemotherapy is used with the intention of shrinking the tumor to facilitate potentially curative surgical treatment in patients with a locally advanced tumor in the absence of metastases.
Early detection of the tumor has improved treatment outcomes in countries such as Japan and Korea, as well as in some Western hospitals.6 In these countries survival after surgery is high (better than 90% after 5 years) thanks to the early diagnosis of the tumor. Complete resection is the treatment mode that has yielded the best results. Technological advances in the diagnosis and treatment of gastric cancer have contributed to the development of less invasive and hence less expensive treatments such as endoscopic mucosal resection and laparoscopy.
In Spain, gastric cancer is considered a disease with a poor prognosis, with a 5-year survival rate of 30%. Suspicious signs and symptoms for gastric cancer, such as weight loss, anemia, dysphagia and vomiting, can fail to lead to a correct diagnosis for months even when patients seek medical attention for their symptoms.5 In some cases the inappropriate use of anti-ulcer medication camouflages the true diagnosis of cancer for some time. Once the cancer is diagnosed, it is often too late to consider surgery as a treatment option.
The delay in diagnosing gastric cancer might be avoided in part if family physicians could promptly request or refer their patients for endoscopic examination. Endoscopy should be advised for all patients older than 45 years who present initially with dyspeptic symptoms, as they make up the subgroup of patients at greatest risk for gastric cancer.6
Some studies have shown that the availability of endoscopic examinations can ensure an earlier diagnosis of suspected cancer, a possibility that would detect the disease at an earlier stage.5 A prompt request for this procedure or referral to a secondary or tertiary center, along with awareness of the urgency of the situation by hospital practitioners, would speed the diagnosis. Differences in the diagnostic process in patients with suspected gastric cancer might also account for some of the geographic differences noted in the article by Ruiz Ramos et al.
In summary, to decrease the incidence of gastric cancer and reduce the gaps between different areas, preventive measures are needed for the general population, and early detection strategies are in order for the population at high risk. Primary care physicians need to be alerted to the potential significance of suspicious symptoms, to improve the chances of an early diagnosis. An efficient system of diagnosis for patients in whom gastric cancer is highly suspected, and the appropriate use of surgical procedures and other treatments, would translate as improvements in survival. Agreed-upon protocols and clinical practice guidelines for gastric cancer are instruments that are likely to facilitate an early diagnosis.
