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Gastric cancer: Difference between revisions
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(Created page with "Gastric adenocarcinoma accounts for 95% of gastric cancers. It’s a cancer of elderly, mostly men, and it’s the fifth most common cancer worldwide. It is more common in Asian countries like Japan and Korea, as well as certain regions in Africa and South America. It causes no or only nonspecific symptoms in the early stages. If diagnosed early, the prognosis is excellent, but at the time of diagnosis, 50% of cancers have already spread and are incurable, which leads t...") |
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Gastric adenocarcinoma accounts for 95% of gastric cancers. It’s a cancer of elderly, mostly men, and it’s the fifth most common cancer worldwide. It is more common in Asian countries like Japan and Korea, as well as certain regions in Africa and South America. | '''Gastric adenocarcinoma''' accounts for 95% of '''gastric cancers'''. It’s a cancer of elderly, mostly men, and it’s the fifth most common cancer worldwide. It is more common in Asian countries like Japan and Korea, as well as certain regions in Africa and South America. | ||
It causes no or only nonspecific symptoms in the early stages. If diagnosed early, the prognosis is excellent, but at the time of diagnosis, 50% of cancers have already spread and are incurable, which leads to a poor prognosis overall. | It causes no or only nonspecific symptoms in the early stages. If diagnosed early, the prognosis is excellent, but at the time of diagnosis, 50% of cancers have already spread and are incurable, which leads to a poor prognosis overall. | ||
The mortality of this cancer is higher in the countries with low prevalence because screening is not performed as often as in high-prevalence countries. Therefore, the cancer is often discovered too late. | The mortality of this cancer is higher in the countries with low prevalence because screening is not performed as often as in high-prevalence countries. Therefore, the cancer is often discovered too late. | ||
Other types of gastric cancer are described at the end of the article. | |||
== Etiology == | == Etiology == | ||
* H. pylori gastritis or other atrophic gastritis | * [[Helicobacter pylori gastritis|H. pylori gastritis]] or other [[atrophic gastritis]] | ||
* Diet rich in nitrates or salts | * Diet rich in nitrates or salts | ||
* Alcohol | * [[Alcohol]] | ||
* Nicotine use | * Nicotine use | ||
* Epstein-Barr virus | * [[Epstein-Barr virus]] | ||
* Gastric adenomas | * Gastric adenomas | ||
* Previous partial gastric resection | * Previous partial gastric resection | ||
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== Diagnosis and evaluation == | == Diagnosis and evaluation == | ||
Physical examination may reveal a tumour in the epigastrium, and an enlarged Virchow’s node (left supraclavicular lymph node). DRE may reveal positive Blumer sign. | Physical examination may reveal a tumour in the epigastrium, and an enlarged [[Virchow node|Virchow’s node]] (left supraclavicular lymph node). [[Digital rectal examination|DRE]] may reveal positive [[Blumer sign]]. | ||
Upper endoscopy is the investigation of choice, as it allows for both visualisation and biopsy. After the diagnosis, CT thorax and abdomen are necessary for staging. | [[Upper endoscopy]] is the investigation of choice, as it allows for both visualisation and biopsy. After the diagnosis, [[CT]] thorax and abdomen are necessary for staging. | ||
If peritoneal carcinosis is suspected but not visible on imaging, laparoscopy may be necessary to visualise the peritoneum and diagnose the carcinosis. Cytology may be obtained from the ascitic fluid. | If [[peritoneal carcinosis]] is suspected but not visible on imaging, laparoscopy may be necessary to visualise the peritoneum and diagnose the carcinosis. Cytology may be obtained from the ascitic fluid. | ||
== Pathology and classifications == | == Pathology and classifications == | ||
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The standard curative surgical treatment for “advanced” gastric cancer patients is radical gastric resection with lymphadenectomy. For intestinal type gastric cancer, distal or subtotal gastric resection is performed. For diffuse type gastric cancer, total gastrectomy is necessary. Afterwards, the <abbr>GI</abbr> system must be reconstructed by Roux-en-Y, Billroth I, or Billroth II. | The standard curative surgical treatment for “advanced” gastric cancer patients is radical gastric resection with lymphadenectomy. For intestinal type gastric cancer, distal or subtotal gastric resection is performed. For diffuse type gastric cancer, total gastrectomy is necessary. Afterwards, the <abbr>GI</abbr> system must be reconstructed by Roux-en-Y, Billroth I, or Billroth II. | ||
[[File:Roux-en-Y procedure.png|thumb|443x443px|A picture showing the pre- and postoperative status of Roux-en-Y procedure]] | [[File:Roux-en-Y procedure.png|thumb|443x443px|A picture showing the pre- and postoperative status of Roux-en-Y procedure]] | ||
The Roux-en-Y reconstruction surgery is the most frequently performed reconstructive surgery of the proximal GI tract, as it prevents bile reflux. The stomach is separated from the bile-containing duodenum by a strand of jejunum 50 cm long. It is difficult to explain how this works, so I’ll allow this image to do the explaining. | The [[Roux-en-Y reconstruction surgery]] is the most frequently performed reconstructive surgery of the proximal GI tract, as it prevents bile reflux. The stomach is separated from the bile-containing duodenum by a strand of jejunum 50 cm long. It is difficult to explain how this works, so I’ll allow this image to do the explaining. | ||
''Billroth I refers to the procedure where the distalmost part of the stomach is resected, and an anastomosis is formed between the duodenum and the remaining distalmost part of the stomach in an end-to-end fashion. This can only be performed if the cancer is located distally in the stomach, close to the pylorus. This procedure is rarely performed anymore, and never in the surgical unit of POTE. Billroth II refers to the procedure where a larger resection of the stomach is performed, and an anastomosis is formed between the side of the duodenum and the side of the remaining stomach in a side-to-side fashion. This procedure allows for a larger resection of the stomach than Billroth I. However, Billroth II allows bile to reflux into the stomach, which causes metaplasia and cancer progression in the remaining stomach or oesophagus. As such, Billroth II is rarely performed anymore, and never in the surgical unit of POTE.'' | ''Billroth I refers to the procedure where the distalmost part of the stomach is resected, and an anastomosis is formed between the duodenum and the remaining distalmost part of the stomach in an end-to-end fashion. This can only be performed if the cancer is located distally in the stomach, close to the pylorus. This procedure is rarely performed anymore, and never in the surgical unit of POTE. Billroth II refers to the procedure where a larger resection of the stomach is performed, and an anastomosis is formed between the side of the duodenum and the side of the remaining stomach in a side-to-side fashion. This procedure allows for a larger resection of the stomach than Billroth I. However, Billroth II allows bile to reflux into the stomach, which causes metaplasia and cancer progression in the remaining stomach or oesophagus. As such, Billroth II is rarely performed anymore, and never in the surgical unit of POTE.'' | ||
Surgery may be used palliatively as well, in cases where the tumour obstructs passage of foodstuffs, for example. A stent may be placed, the stomach may be resected, or bypass surgery may be employed. | Surgery may be used [[Palliative care|palliatively]] as well, in cases where the tumour obstructs passage of foodstuffs, for example. A stent may be placed, the stomach may be resected, or bypass surgery may be employed. | ||
Chemotherapy may be used neoadjuvant for downstaging (to allow for surgery with curative intent), as adjuvant therapy, and as palliative therapy. | Chemotherapy may be used [[Neoadjuvant therapy|neoadjuvant]] for downstaging (to allow for surgery with curative intent), as [[adjuvant therapy]], and as palliative therapy. | ||
= Other gastric cancers = | == Other gastric cancers == | ||
== Gastrointestinal stroma tumor (GIST) == | === Gastrointestinal stroma tumor (GIST) === | ||
This type of tumor is the most common mesenchymal tumor from the interstitial Cajal-cells. It can occur anywhere in the <abbr>GI</abbr>-tract, but is most commonly found in the stomach, followed by the duodenum. | This type of tumor is the most common mesenchymal tumor from the interstitial Cajal-cells. It can occur anywhere in the <abbr>GI</abbr>-tract, but is most commonly found in the stomach, followed by the duodenum. | ||
The C-kit gene, which encodes for a tyrosine kinase, is often mutated in the patients with GIST. The mutated tyrosine kinase becomes constitutively activated, causing nonstop activation of the downstream effects and progression to cancer. | The [[C-kit]] gene, which encodes for a [[tyrosine kinase]], is often mutated in the patients with GIST. The mutated tyrosine kinase becomes constitutively activated, causing nonstop activation of the downstream effects and progression to cancer. | ||
Morphologically, the tumor can either be submucous, subserous or intramural. The submucous one is often ulcerated and polypus. | Morphologically, the tumor can either be submucous, subserous or intramural. The submucous one is often ulcerated and polypus. | ||
Treatment is by surgery with or without the addition of tyrosine kinase inhibitor (imatinib), a drug which blocks the mutated tyrosine kinase. | Treatment is by surgery with or without the addition of [[tyrosine kinase inhibitor]] (imatinib), a drug which blocks the mutated tyrosine kinase. | ||
== Gastric lymphomas == | === Gastric lymphomas === | ||
Lymphomas can arise in every tissue, but the stomach is the most common site of extranodal lymphoma. However, it’s still one of the rarest malignancies that you can have there. The lymphomas include: | Lymphomas can arise in every tissue, but the stomach is the most common site of extranodal lymphoma. However, it’s still one of the rarest malignancies that you can have there. The lymphomas include: | ||
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* DLBCL – diffuse large B-cell lymphoma | * DLBCL – diffuse large B-cell lymphoma | ||
=== MALT lymphoma of the stomach === | ==== MALT lymphoma of the stomach ==== | ||
MALT lymphoma is a | MALT lymphoma is a form of [[marginal zone lymphoma]] originating from B-cells in the MALT. It’s caused by [[Helicobacter pylori gastritis|H. pylori gastritis]]. The bacteria secrete the endotoxin CagA that leads to B-cells proliferation and autoreactive B-cells. These events eventually lead to a lymphoma. Treatment is by treating the H. pylori infection, which causes the lymphoma to regress. | ||
=== DLBCL – diffuse large B-cell lymphoma === | ==== DLBCL – diffuse large B-cell lymphoma ==== | ||
DLBCL is more aggressive than MALT lymphoma, and can either be primary (de novo), or secondary following the transformation of a MALT-lymphoma. | [[Diffuse large B-cell lymphoma|DLBCL]] is more aggressive than MALT lymphoma, and can either be primary (de novo), or secondary following the transformation of a MALT-lymphoma. | ||
[[Category:Gastrointestinal surgery]] | [[Category:Gastrointestinal surgery]] | ||
[[Category:Gastroenterology]] | [[Category:Gastroenterology]] | ||