Gastric adenocarcinoma, commonly referred to as gastric cancer, refers to a primary malignancy arising from the gastric epithelium. It is the most common gastric malignancy.
Gastric cancer is rare before the age of 40, but its incidence steadily climbs after that and peaks in the seventh decade of life 2. The median age at diagnosis of gastric cancer in the United States is 70 years for males and 74 years for females.
It often produces no specific symptoms when it is superficial and potentially surgically curable, although up to 50% of patients may have nonspecific gastrointestinal complaints such as dyspepsia 2.
Patients may present with anorexia and weight loss (95%) as well as abdominal pain that is vague and insidious in nature. Nausea, vomiting, and early satiety may occur with bulky tumours that obstruct the gastrointestinal lumen or infiltrative lesions that impair stomach distension 2.
Several nodal metastases with eponymous names associated with gastric cancer have been described:
Adenocarcinoma is by far the most common gastric malignancy, representing over 95% of malignant tumours of the stomach 1.
Gastric cancer continues to be one of the leading causes of cancer-related death. A significant development in the epidemiology of gastric carcinoma has been the recognition of the association with Helicobacter pylori infection. Most gastric cancers occur sporadically, whereas 8-10% have an inherited genetic component.
- pernicious anaemia 7
- adenomatous gastric polyps 7
- atrophic gastritis 7
Billroth II partial gastrectomy for benign disease (e.g. peptic ulcer disease)
- reflux of bile and pancreatic juice as thought to be carcinogenic 8
- type A blood group 9
Endoscopy is regarded as the most sensitive and specific diagnostic method in patients suspected of harbouring gastric cancer. Endoscopy allows direct visualisation of tumour location, the extent of mucosal involvement, and biopsy (or cytologic brushings) for tissue diagnosis 3. But radiological methods are often the initial examination that raises suspicion for gastric carcinoma, besides being used in the staging of the disease.
Early gastric cancer (elevated, superficial, shallow):
- type I: elevated lesion, protrudes >5 mm into the lumen (polypoid)
- type II: superficial lesion (plaque-like, mucosal nodularity, ulceration)
- type III: shallow, irregular ulcer crater with adjacent nodular mucosa and clubbing/fusion/amputation of radiation folds 4
Advanced gastric cancer:
- polypoid cancer can be lobulated or fungating
- lesion on a dependent or posterior wall; filling defect in barium pool
- lesion on non-dependent or anterior wall; etched in white by a thin layer of barium trapped between edge of mass and adjacent mucosa
- ulcerated carcinoma (penetrating cancer): 70% of all gastric cancers 4
Not useful, unless a large epigastric mass is present or on endoscopic ultrasound study.
CT is currently the staging modality of choice because it can help identify the primary tumour, assess for the local spread, and detect nodal involvement and distant metastases 1.
Demonstration of lesions facilitated by negative contrast agents (water or gas):
- a polypoid mass with or without ulceration
- focal wall thickening with mucosal irregularity or focal infiltration of the wall
- ulceration: gas-filled ulcer crater within the mass
- infiltrating carcinoma: wall thickening and loss of normal rugal fold pattern 4
Calcifications are rare but when present, they are usually mucinous adenocarcinoma.
Treatment and prognosis
It is an aggressive tumour with a 5-year survival rate of less than 20%. Prognosis is correlated to the stage of the tumour at presentation. Therefore, accurate staging of gastric cancer is essential because surgical resection is the treatment for localised disease 1.
- perforation with peritonitis: rare (thought to occur in ~2% of cases) 5,6
The imaging differential can be broad and includes:
- 1. Horton KM, Fishman EK. Current role of CT in imaging of the stomach. Radiographics. 23 (1): 75-87. doi:10.1148/rg.231025071 - Pubmed citation
- 2. Gore RM. Gastric cancer. Clinical and pathologic features. Radiol. Clin. North Am. 1997;35 (2): 295-310. - Pubmed citation
- 3. Dicken BJ, Bigam DL, Cass C et-al. Gastric adenocarcinoma: review and considerations for future directions. Ann. Surg. 2005;241 (1): 27-39. Ann. Surg. (link) - Free text at pubmed - Pubmed citation
- 4. Federle MP, Jeffrey RB, Woodward PJ et-al. Diagnostic Imaging: Abdomen, Published by Amirsys®. Lippincott Williams & Wilkins. (2009) ISBN:1931884714. Read it at Google Books - Find it at Amazon
- 5. Roviello F, Rossi S, Marrelli D et-al. Perforated gastric carcinoma: a report of 10 cases and review of the literature. World J Surg Oncol. 2006;4 : 19. doi:10.1186/1477-7819-4-19 - Free text at pubmed - Pubmed citation
- 6. Kotan C, Sumer A, Baser M et-al. An analysis of 13 patients with perforated gastric carcinoma: A surgeon's nightmare? World J Emerg Surg. 2008;3 : 17. doi:10.1186/1749-7922-3-17 - Free text at pubmed - Pubmed citation
- 7. Weissleder R, Wittenberg J, Harisinghani MMGH et-al. Primer of Diagnostic Imaging. Mosby. (2011) ISBN:0323065384. Read it at Google Books - Find it at Amazon
- 8. Filez L, Penninckx F. Surgery for gastric remnant carcinoma following Billroth II gastrectomy. In: Holzheimer RG, Mannick JA, editors. Surgical Treatment: Evidence-Based and Problem-Oriented. Munich: Zuckschwerdt; 2001. Available from: http://www.ncbi.nlm.nih.gov/books/NBK6885/
- 9. Edgren G, Hjalgrim H, Rostgaard K et-al. Risk of gastric cancer and peptic ulcers in relation to ABO blood type: a cohort study. Am. J. Epidemiol. 2010;172 (11): 1280-5. doi:10.1093/aje/kwq299 - Pubmed citation