Oscar M. Laudanno, Ronald Estrada Seminario
Stomach cancer, usually an adenocarcinoma, can be divided into two categories: the diffusive type, with individual cells that infiltrate and increase the thickness of the gastric wall, and the intestinal type, characterized by neoplastic cells that form glandular-like structures.
From the point of view of pathological anatomy, Bormann's classification of advanced cancer is still valid, which I divide into types I, II, III and VI. Type I is a vegetative fungal carcinoma that crosses the mucosa, submucosa, and muscle layer; type II is a carcinomatous ulceration with infiltration of the surrounding mucosa, and type IV is diffuse infiltrating carcinoma, which can lead to linitis plastica. Bormann II and II cancers can be mistaken for a type III benign gastric ulcer. Almost all gastric cancers are adenocarcinomas, with lymphomas, sarcomas, and carcinoids being rare.
Symptoms and signs
Early gastric cancer is generally asymptomatic. Sometimes the patient may refer dyspeptic symptoms, indigestion, which do not motivate the consultation; other times he has hematemesis or a mane, a good opportunity to detect cancer early. The most important thing is that early gastric cancer in its depressed forms, ulcerative type, and in particular III, simulates a benign gastric ulcer macroscopically and also in its symptoms; ulcerative syndrome is generally atypical, with a malignant cycle similar to the benign cycle of gastric ulcer, and periodicity, since ulcerated cancer can appear and clear three, four, or more times over a period of eight to ten years. It is essential to keep this period of time in mind since the neoplasm is of slow evolution,
Advanced gastric cancer is characterized by anorexia, early satiety, disgust with meats and generally with all foods, including cigarettes; there is progressive weight loss and an anemic syndrome, with asthenia, adynamia, dyspnea on exertion, paleness, and palpitations. Gastric cancer patients generally lose a small amount of blood, which is detected by fecal occult blood tests; although they can also give melena and / or hematemesis. Continuous epigastric pain that does not relieve with the trunk flexed or in prone position, in manifestation of advanced neoplasia. It can give a prolonged febrile syndrome, as it ulcerates and becomes infected, simulating lymphoma. The physical examination in these circumstances shows a patient pale, thin or with a palpable, fixed, consistent epigastric tumor; or with a metastatic type nodular liver, or with a fixed umbilicus, or with nodes in the left supraclavicular fossa, Troisier type. In women, a take can be palpated in the left iliac fossa, simulating an ovarian neoplasia, which corresponds to Krukenberg-type metastasis. Finally, the patient can consult for abdominal distension, with moving liquid dullness, obtaining in the abdominal puncture a bloody liquid, such as washed meat water, whose physicochemical study reveals an exudate.
More early, when the tumor involves the cardia or the pylorus, it manifests dysphagia and pyloric syndrome, respectively.
Regarding laboratory studies, the hemogram in advanced cancer will show hypochromic microcytic anemia (due to hemorrhage) and sometimes hyperchromic macrocytic anemia (pernicious anemia with gastric cancer); the investigation of occult blood in fecal matter (test of guaiac or of the benzidina) will give generally positive. Routine erythrocyte sedimentation is normal.
The gastroduodenal serial radiography with double contrast allows to appreciate small depressed, elevated lesions, stiffness, distorted gastric folds, etc., of the size of 1 cm or less, according to the experience of the radiologist or gastroenterologist.
Conventional gastrectomy serial radiology may still be used to diagnose advanced gastric cancer; in such circumstances it is possible to observe crude lacunar images of lack of filling, or localized hourglass-like stiffness, or the signs of a plastic linitis.
When there are definitive signs of malignant gastric ulcer, when the study is indeterminate or there are signs of a space-occupying mass-type lesion or an infiltrative process, an endoscopic examination with tissue biopsy should be performed . The endoscopic appearance alone is inadequate to provide a definitive diagnosis; tissue must be obtained for pathologic examination. When space-occupying mass-type lesions are found, especially where the overlying mucosa appears to be normal, it is important to obtain a deep biopsy specimen that extends into the submucosa. Good technique involves repeated biopsy shots at the same biopsy site, so that each shot reaches deeper into the gastric wall.
When ulcers are observed, it is necessary to obtain at least six biopsy samples, from the overlying border and the base of the ulcer, to increase the diagnostic yield.
After the initial diagnosis of gastric adenocarcinoma is confirmed by endoscopy and biopsy, evidence of distant metastasis should be sought by clinical examination, chest radiography, and liver function tests. If the clinical examination and the usual laboratory tests do not raise the suspicion of distant metastasis, a computed tomography (CT) scan may be indicated to confirm the absence of these. Abdominal CT allows the identification of liver metastases and helps in the evaluation of perigastric involvement.
The endoscopic ultrasound may have an accuracy of up to 90% in defining the depth of invasion and therefore the distinction between early and advanced gastric cancers.
Early gastric cancer
It is defined as early gastric cancer in which the lesion is limited to the mucosa, eventually to the submucosa, without invading the muscle layer, with or without lymph node metastases. Eventual lymph node metastases lie in nodes that are automatically removed when subtotal gastrectomy is performed and therefore do not invalidate the good prognosis or the concept of early gastric cancer.
According to the Japanese classification, early stomach cancer is divided into three types: a) type I (prominent), protruding into the gastric cavity, b) type II (superficial), with subtypes IIa (elevated), IIb (flat) and IIc (depressed), and c) type III (excavated).
Since the main criterion for the classification of gastric cancer is the penetration of the carcinoma, it is important to establish that neither the radiological nor the endoscopic examination provides differentiation between early and advanced cancer. This differentiation is only possible with the histopathological examination of the resected stomach.
The japanese Okuda reclassified early gastric cancer into eight types, in order to be able to determine, through a more final description of the macroscopic morphology, the depth reached by the lesion. In any case, an advanced gastric cancer can be considered when the size is greater than 2 cm and has an uneven central depression, as well as if the convergence of folds shows their termination away from the ulcer bed, or when it presents the head shape of the Phorphorus, pinned, which is indicating a compromise of the muscularis mucosae and even the muscular layer.