Gastric Cancer

1. Gastric Cancer

2. Gastric Cancer Worldwide, gastric adenocarcinoma is the second most common cause of cancer death (second to lung cancer). Approximately 95% of all malignant gastric neoplasms are adenocarcinomas. The remaining tumors are lymphomas, carcinoids, or sarcomas. Gastric adenocarcinomas are divided into 2 types: 1.An intestinal type,with well-formed glandular structures: This is more likely to involve the distal stomach and to occur in patients with atrophic gastritis. This type has a strong environmental association. 2.A diffuse type,with poorly cohesive cells that tend to infiltrate the gastric wall: Tumors of this type may involve any part of the stomach, especially the cardia, and they have a worse prognosis. Unlike type 1 gastric cancers, type 2 cancers have a similar frequency in all geographic areas.

3. Gastric Cancer • Frequency: • In the US: • The incidence has decreased from 33 cases per 100,000 population in 1930 to 3.7 cases per 100,000 population in 1990. • Internationally: • Worldwide, gastric adenocarcinoma is the second most common cause of cancer death (second to lung cancer). • The highest incidence (>30 cases per 100,000 population) is in Russia, China, South America, and Eastern Europe. • The incidence of gastric cancer is extremely high in Japan, Chile, and Iceland. • The lowest incidence (<3.7 cases per 100,000 population) is in Africa Age-standardized Incidence Rates for Stomach Cancer. From: Global Cancer Statistics, 2002 -- Parkin et al_ 55 (2) 74 -- CA A Cancer Journal for Clinicians

4. Gastric Cancer ClinicalPresentation: Most patients present with advanced disease because they are often asymptomatic in the earlier stages. Common presenting features are epigastric pain, bloating, early satiety, nausea, vomiting, dysphagia, anorexia, weight loss, and upper GI bleeding (hematemesis, melena, iron deficiency anemia, positive results with fecal occult blood tests). Gastric carcinoma is twice as common in men than in women. Gastric carcinoma has a peak incidence in patientsaged 50-70 years. However, approximately 5% of patients with gastric cancer are younger than 35 years and 1% are younger than 30 years. Younger patients have more aggressive lesions with a worse prognosis.

5. Gastric Cancer Preferred Examination: 1. Begin the evaluation with history taking and physical examination. 2. Perform blood tests, including a full blood count determination and liver function tests. 3. Inspect the stool, and test for occult blood. 4. Perform either fiberoptic endoscopy or a double-contrast study (barium and gas) of the upper GI tract. • Endoscopy has become the diagnostic procedure of choice for patients with suspected gastric carcinoma. Biopsy samples obtained during endoscopy enable histologic diagnosis. However, endoscopy is more invasive and more costly than a double-contrast study. • Double-contrast examinations of the upper GI tract remain a useful alternative to endoscopy and have similar sensitivity in the detection of gastric cancer. 5. CT, MRI, and endoscopic ultrasonography (EUS) are used in staging but not usually in the primary detection of gastric cancers

6. Gastric Cancer Radiologic features Early gastric cancer - lesion confined to the mucosa or submucosa In Western counties, early gastric cancers account for only 5-20% of all gastric cancers. In Japan, they represent 25-46% owing to the population-screening program that was implemented to combat the high incidence of the disease. Double-contrast upper GI examination is widely recognized as the radiologic technique of choice for diagnosing early gastric cancers. These lesions are confined to the mucosa or submucosa and are classified into 3 types.

7. Gastric Cancer Radiologic features Early gastric cancer Type I lesions are elevated and protrude more than 5 mm into the lumen. From: http://www.kgan.minami.fukuoka.jp

8. Gastric Cancer Radiologic features Early gastric cancer Type II tumors are superficial lesions that are elevated (IIa), flat (IIb), or depressed (IIc). From: http://www.kgan.minami.fukuoka.jp

9. Gastric Cancer Radiologic features Early gastric cancer Type III early gastric cancers are shallow, irregular ulcers surrounded by nodular, clubbed mucosal folds. Type 0/III (III+IIc) Excavatedand superficial depressed type From: http://www.kgan.minami.fukuoka.jp

10. Gastric Cancer Radiologic features • Advanced carcinoma • On barium studies, gastric carcinomas may be polypoidal, ulcerative, or infiltrating lesions. Morphologic types of gastric cancer Polypoidal Ulcerative Diffuse

11. Gastric Cancer Advanced carcinoma - polypoidal lesion Polypoid carcinomas are lobulated masses that protrude into the lumen. They may contain 1 or more areas of ulceration. Extensive carcinoma involving the cardia and fundus.

12. Gastric Cancer Advanced carcinoma - polypoidal lesion Carcinoma of the cardia with involvement of the distal esophagus

13. Gastric Cancer Advanced carcinoma - ulcerative lesion With ulcerated carcinomas, an irregular crater is located in a rind of malignant tissue. Seen in profile, these lesions are intraluminal, whereas benign ulcers project beyond the contour of the stomach.

14. Gastric Cancer Advanced carcinoma - infiltrating carcinoma Infiltrating carcinomas result in irregular narrowing of the stomach

15. Gastric Cancer • Scirrhous carcinoma • typically causes irregular narrowing of the stomach

16. Gastric Cancer Scirrhous carcinoma - narrowing of the pylorus

17. Gastric Cancer Endoscopy is less reliable in the diagnosis of scirrhous tumors (35-70%) then in the diagnosis of other types of carcinoma (95%). „In conclusion, UGI series is definitely superior to endoscopic examination in correct tumor localization and diagnosis of scirrhous gastric carcinoma.” Double-contrast barium image obtained with the patient in the supine position shows thickened and irregular folds with relatively mild loss of distensibility in the body. Photograph obtained during endoscopy reveals circumferentially infiltrating lesion with erythematous mucosal change in the body of the stomach. The biopsy specimen was negative for malignancy. From: Radiology 2004;231:421-426.Scirrhous Gastric Carcinoma: Endoscopy versus Upper Gastrointestinal Radiography, Mi-Suk Park, et al.

18. Gastric Cancer Scirrhous carcinoma Scirrhous carcinomas typically cause irregular narrowing and rigidity of the stomach, giving rise to the typical linitis plastica, or leather-bottle appearance Linitis plastica may be suggested by satiety, a never-changing shape of the stomach on barium x-ray.

19. Gastric Cancer Scirrhous carcinoma Linitis Plastica:      -    diffuse infiltration     -    decreased peristalsis     -    endoscopic biopsy may be negative  There is a marked narrowing of almost the complete stomach.  This is due to diffuse infiltration of the gastric wall by a scirrhous adenocarcinoma.

20. Gastric Cancer Scirrhous carcinoma Gastric carcinomas are occasionally seen on plain abdominal radiographs as abnormalities in the gastric contour or as soft-tissue masses indenting the gastric contour.

21. Gastric Cancer CAT SCAN CT is primarily used to preoperatively assess patients with gastric carcinoma.The main role of CT is to identify patients who would not benefit from radical surgery. CT is used to stage the tumor and also to monitor the response to treatment. • CT scans may show the following: • Polypoidal mass with or without ulceration • Focal wall thickening with mucosal irregularity or ulceration • Wall thickening with the absence of normal mucosal folds (infiltrative lesions) • Focal infiltration of the gastric wall • Variable thickening of the wall and marked contrast enhancement (typical of scirrhous lesions) • Mucinous carcinomas, which have low attenuation due to their high mucin content and which may contain calcification

22. Gastric Cancer CAT SCAN • T staging • The depth of tumor invasion is not accurately assessed with CT. • Invasion of the perigastric fat is seen as soft tissue stranding. • Direct extension of the tumor is relatively common. • N staging • CT depicts 75% of nodes larger than 5 mm in diameter • In the new TNM classification, nodal staging is related to the number of regional nodes involved in the perigastric group and around the celiac axis. • Enlarged nodes elsewhere (eg, in the retroperitoneum and mesentery) are classified as distant metastases. • N1 indicates 1-4 nodes; N2: 7-15 nodes; and N3 more than 15 nodes.

23. Gastric Cancer CAT SCAN T3 gastric cancer: Consecutive axial helical CT scans show no significant change in attenuation of pancreas and relatively distinct fat plane between pancreas and gastric lesion. From: AJR 2000; 174:1551-1557Comparing MR Imaging and CT in the Staging of Gastric Carcinoma, Kyung-Myung Sohn et al.

24. Gastric Cancer CAT SCAN T4 gastric cancer Tumor extension to the distal esophagus and the crural diaphragm

25. Gastric Cancer CAT SCAN T4 gastric cancer: Axial helical CT image shows pancreatic invasion by gastric tumor (CTT4) (arrows). Note poor demarcation of lesion from adjacent bowel. P = head of pancreas. From: AJR 2000; 174:1551-1557Comparing MR Imaging and CT in the Staging of Gastric Carcinoma, Kyung-Myung Sohn et al.

26. Gastric Cancer CAT SCAN • M staging • Because the portal vein drains the stomach, the liver is the most common sitefor hematogenous metastases.Less common sites are the lungs, adrenal glands, and kidneys. • Intraperitoneal and omental metastases are common in advanced gastric cancer. • Gastric carcinoma is the most common primary tumor to metastasize to the ovaries. The ovarian metastases are usually bilateral and known as Krukenberg tumors.

27. Gastric Cancer MRI Recent studies in which a breath-hold fast imaging technique and water were as a luminal contrast agent have shown accuracy rates comparable to those of helical biphasic CT. MRI is limited by respiratory and peristaltic artifacts, the lack of suitable oral contrast media, and is higher cost compared with CT.

28. Gastric Cancer MRI A T4 gastric cancer. Axial unenhanced (A) T1-weighted MR images and helical CT scan (B) show concentric tumor in gastric antrum. Small tumor infiltration in gallbladder wall (arrowheads, A) is well seen on A but not on B. B From: AJR 2000; 174:1551-1557Comparing MR Imaging and CT in the Staging of Gastric Carcinoma, Kyung-Myung Sohn et al.

29. Gastric Cancer ULTRASOUND • The primary role of transabdominal ultrasonography is to detect liver metastases. • CT and EUS are complementary. • CT is used first to stage the gastric carcinoma. If CT shows no metastases and no invasion of local organs, EUS is used to refine the local stage. • The depth of tumor invasion is not accurately assessed with CT, and the investigation of choice for this indication is endoscopic EUS.

30. Gastric Cancer ULTRASOUND An irregular heterogenous polypoid tumor can be seen extending into the submucosa. The underlying hypoechoic layer corresponding to the muscularis propria remains intact. The hypoechoic layer corresponding to the muscularis propria has been breached by an irregular hypoechoic tumor(arrow) with complete disruption of the gastric wall layer structure.

31. Gastric Cancer Algorithm for the work-up of a patient with symptoms suspicious for gastric cancer. (CT = computed tomography EUS = endoscopic ultrasonography) From: Am Fam Physician. 2004 Mar 1;69(5):1133-40.Gastric cancer: diagnosis and treatment options.Layke JC, Lopez PP.