In some of our observations, the double-contrast investigation proved to be the only effective tool to diagnose cancer of the greater curvature at its initial stage. Another field of application of this method is target endoscopy, during which tissue specimens are taken from the zone where X-ray examination has suspected the presence of a tumor. Bioptates are taken using instruments (aspiration, needle, »hot« biopsy, etc.) specially designed for taking tissue specimens from the submucous coat. But G. Caletti et al. (1989) indicate that these methods often prove ineffective. Verification of the site for taking tissue specimens by staining the mucous membrane of the stomach affected by superficially growing tumor, which is effective in 95-97% of cases, becomes infeasible with submucous spread of the tumor [24]. X-ray findings become decisive in such cases.

Close cooperation between a radiological diagnostician and an endoscopist is the guarantee of successful detection of gastric cancer. Japanese researchers united radiology and endoscopy in a single program for examination of risk groups for gastric cancer, based on standardized semiotics, methodology, and surgical treatment, to attain unprecedented success in diagnosis and treatment.

Ulcerated tumors occur mostly on the greater curvature. Although they are possible to diagnose at present, they nevertheless remain a serious problem in gastroentero-ocology. Difficulties that arise in revealing tumor substrate on the greater curvature add to the problems of differentiating between benign and malignant ulcerations. Additional problems arise with signs which are not characteristic of typical cancer ulcers. Either they are difficult to identify or they resemble common peptic ulcer. X-ray examinations in such cases revealed depression on the contour and a niche (as distinct from blasto-matous ulceration of the lesser curvature, which extends beyond the limits of the stomach contour in rare cases). The ridge of infiltrated tissue is more pronounced; the folds may converge not toward the ulcerated site but toward the infiltration ridge (D Fig. 146) [46].

Specific ulceration of the greater curvature and differential diagnosis became the subject of concern of oncologists early in the twentieth century, at the dawn of roentgenology. Holmes and Hempton (1932) concluded from their observations that all ulcers of this localization require surgery. Smith and Jordan (1948) strengthened the opinion that ulcers on the greater curvature are malignant in 60% cases. Bour-deau et al. (1951) and McClone and Robertson (1953) revealed malignant ulceration of the greater curva ture in 49 -56% of all ulcers of the stomach. This concern of the specialists was shared by radiologists.

In the 1950s and 1960s, many publications dealt with the problem of X-ray diagnosis of malignant and benign ulcers of the greater curvature. They all reflected the inability of classical radiology, based on the traditional method of tight filling, to establish definite criteria for differential diagnosis of these conditions. Signs of malignant ulcers (convergence of mucosal folds toward the ulcer, their termination at the infiltration ridge, location of the niche within the confinements of the stomach contours, etc.), which are more characteristic of pathologies of the lesser curvature, are often useless in conditions affecting the anatomical and functional properties of the greater curvature.

We want to explain our opinion on infiltrative cancer of the greater curvature based on the results of studies using traditional methods and the double-contrast technique with obligatory endoscopy as an additional tool of examining the abdominal cavity and the stomach (in recent years we have also used ultrasonogrpaphy, CT, or MRI). Our experience shows that a methodologically correct examination can reveal some signs that are quite specific for infiltrative-ulcerous cancer. The most important of these, which help to establish the radiological diagnosis, are the following: irregular shapes of the ulcer crater with overhanging and eroded contours, walls thickened to various degrees and to various lengths, upset peristalsis, and elasticity of the stomach walls.

We want to note again that with discovery of any ulcer of the stomach, and especially on its greater curvature, the main objective of the radiological diagnostician is to rule out blastomatous infiltration. Even with dynamic observation during treatment of the patient, in cases where endoscopic signs of ulceration disappear, only the stability of intramural changes helps the physician to avoid fatal diagnostic errors.

The greater curvature is more frequently affected by blastomatous process of mostly diffuse character than was believed in the 1990s. Therefore, discovery of signs of cancer infiltration at this localization must suggest the use of »extreme« technologies: ingestion of greater amounts of contrast medium, maximum permissible inflation of the stomach. These measures give more accurate information on the presence or absence of infiltrative cancer of the greater curvature of the stomach with or without ulceration.

To conclude this section, it is necessary to note that, like cancer of the anterior wall, cancer of the greater curvature has many »latent« aspects which should be considered today by both diagnosticians and clinicians. First and foremost is the considerably greater percentage of endophytic (diffuse) cancers at their early stages, and also the important role of updated means of radiological diagnosis such as ultrasonography, CT, and MRI in their detection.

Cancer of the Anterior Wall

Even today popular opinion holds that cancer of the anterior wall is an extremely rare incidence. In supporting of this point of view, allusion is made to the absence of statistical data on the frequency of new growths at this localization in the great majority of publications. Based on our experience, we do not agree with this opinion. The more so that some other authors have the same view of this problem as ours (T. Hirota et al. 1984; W. Meyer et al. 1987). They indicate the tendency to an increasing proportion of cancers of the anterior wall. D. Brandt et al. (1989) state that the percentage of cancer of the anterior wall in the antral part of the stomach is the same as that of tumors located on the posterior wall in this part of the stomach. Our opinion on this problem coincides with that of researchers who believe that the anterior wall is the site where gastric cancer occurs more frequently than is believed by many authors. But diagnosis of new growths at this localization is difficult because their possibility is underestimated. Cancer of the anterior wall does not show clinically until evacuation dysfunction of the stomach or of the esophagus develops due to severe circular narrowing of the organ. This usually happens in patients with far advanced cancer when it is no longer possible to locate the primary site of the tumor. Screening programs developed in Japan make it possible to significantly improve detection of primary cancers of the anterior wall. This stimulated researchers in other countries to take a new look at the problem [143,

239]. Our research also confirms this standpoint [31, 34, 223, 224].

The special methodological approach to diagnosis of cancer of the anterior wall consists in special projections for this region of the stomach body and its antral part, and in using additional techniques such as »mild and incomplete« compression under fluoroscopy guidance (D Fig. 147). The non-standard nature of anterior wall imaging made roentgenolo-gists pay special attention to the examination procedure itself. This involved changes in methodology. Thus, Hisamichi et al. [144] recommended that the patient ingest the first portions ofbarium sulfate suspension in the prone position, which gives unexpected results. Roentgenological screening conducted by this method revealed a markedly increased incidence of early cancers of the anterior wall of the stomach [142, 143].

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