Stomach Cancer: Causes, Symptoms, Staging, Diagnosis and Treatment
Stomach cancer is also known as gastric carcinoma is a disease in which cancerous (malignant) cells form in the lining of the stomach.
There are several predisposing factors to gastric cancer including:
Predisposing factors to stomach cancer
- Helicobacter pylori infection
- Gastric ulcers
- Chronic gastritis-atrophic or pernicious anemia
- Gastric adenomas
- Cigarette smoking and alcohol consumption
- Nitrosamines in the preservation of foods
- Partial gastrectomy-bilious reflux
- Barrets esophagus
- Radiation therapy
- Genetic Factors
Signs and Symptoms of stomach cancer
From history, most gastric cancer patients present at an advanced stage with non-specific symptoms that can be summarized by -5A’s
(Asthenia, Abdominal pain, Anorexia, Anaemia Achlorhydria)
1.Weight loss (asthenia) most common symptom
2. Abdominal pain may be epigastric, substernal, or back. Abdominal pain may mimic that of benign peptic ulcer disease, with a relief of pain obtained by ingesting antacids, H2-blockers, and food. In other patients, pain is worse after eating
3. Anorexia and vomiting are present, especially if distal tumors cause pyloric obstruction. There is also associated dyspepsia and early satiety.
4. Constipation because of reduced dietary intake, this is common.
5. Both acute and chronic upper gastrointestinal bleeding may occur, with hematemesis and melena, though frank hemorrhage occurs infrequently, usually in less than 10% of patients.
6. Anemia is another common finding in these patients. They will present with weakness and fatigue related to anemia and also due to weight loss due to decreased dietary intake. Worsening angina pectoris and dyspnea may be related to progressive anemia.
7. Dysphagia is an important symptom of adenocarcinoma of the fundus of the stomach, which involves the cardio esophageal junction.
Symptoms suggestive of metastasis include:
Jaundice may be present secondary to liver metastasis or extension of cancer into the porta hepatis.
Large bowel involvement by metastasis spreading through the gastrocolic ligament may be mistaken for primary colonic cancer and may cause large intestinal obstruction.
Bone pain or neurologic symptoms of cord compression signal metastatic disease.
Predisposing factors to stomach cancer
- Alcohol intake
- Cigarette smoking
- History of treatment for peptic ulcer disease either a gastric ulcer or H. pylori
- History of GIT cancer
- Familial history
Physical examination may not reveal abnormality except in advanced disease. The findings that can be prominent are;
Jaundice may be present if liver metastases are extensive or positioned at the porta hepatis
Recent weight loss with temporal wasting and loss of muscle mass. The patients may also be dehydrated
Lymph node enlargement, particularly in the left supraclavicular area (or Virchow's signal node) or the left side of the neck. Termed Troisier’s sign
Umbilical nodules indicate the presence of metastatic disease.(Sister Mary Joseph’s sign)
Palpable abdominal mass if the cancer is large or hepatic enlargement related to metastatic disease, gastric dilatation, and a succussion splash.
Malignant ascites can occur with metastatic gastric cancer.
Rectal examination may reveal a rectal "shelf" (Blumer's shelf). Metastases are thought to spread by gravity to the true pelvis and form the shelf noted on rectal examination.
Rarely, acanthosis nigricans may be found on examination of the patient's skin, particularly in the axillae or other body folds.
ovarian metastases (Krukenberg tumor)
Superficial thrombophlebitis on the legs (Trousseau's sign), It is also associated with pancreatic cancer.
Diagnostic Investigations in stomach cancer
1. Gastroscopy, biopsy, and cytology are the gold standard for diagnosis
Upper gastrointestinal endoscopy provides the best overall method of diagnosing gastric cancer. Both biopsy and brush cytologic evaluation should be done because they are complementary.
In general, the more biopsies obtained, the higher the diagnostic yield. At least four to six biopsy specimens should be obtained from each separate lesion for histology.
2.Barium meal with double-contrast(with Air)
In the absence of an upper GI endoscopy, this can be done. Some of the abnormalities noted include
- Lack of distensibility of the stomach
- An ulcerated mass or mass effect surrounding an ulcer
- A mass in any portion of the stomach
- Enlarged gastric folds
- Obstructing lesions at the cardio esophageal junction or at the pylorus.
Endoscopic ultrasonography combines endoscopy and ultrasonography to produce detailed images of the stomach wall allowing an accurate assessment of depth of tumor invasion.
It is more accurate in assessing the depth of cancer invasion and also appears to be more accurate in determining cancer spread to regional lymph nodes.
CT-Scan is used to evaluate gastric wall thickness, a direct extension of tumor into adjacent organs, regional and retroperitoneal lymph node enlargement, ascites, and liver metastases thus stage the tumor.
CT-Scan has been shown to predict with reasonable accuracy which patients can undergo curative surgery and which tumors are unresectable.
Abdominal ultrasound enables one to visualize the seeding of peritoneum and in females, the krunkenburg tumors.
Laparoscopy enables one to;
- Stage of the tumor
- Assess Lymph node involvement
- Perform biopsy for diagnosis
- Perform peritoneal washout for cytology
- Check on the operability of the tumor
7.Chest X-Ray for thoracic involvement
8Positron emission tomography (PET) or PET-CT scan. A PET scan is usually combined with a CT scan, called a PET-CT scan. A PET scan is a way to create pictures of organs and tissues inside the body. A small amount of a radioactive sugar substance is injected into the patient’s body.
This sugar substance is taken up by cells that use the most energy. Because cancer tends to use energy actively, it absorbs more of the radioactive substance. A scanner then detects this substance to produce images of the inside of the body.
1. Full hemogram to aid in the evaluation of the anemia. A microcytic hypochromic picture is present due to chronic blood loss but may also be megaloblastic in pernicious anemia.
2.Liver function tests in jaundiced patients
These tests facilitate the evaluation of the bilirubin, alkaline phosphatase, and 5'-nucleotidase may indicate metastatic liver disease.
3.Carcinoembryonic antigen (CEA)
The concentration of carcinoembryonic antigen may be elevated in patients with gastric cancer, usually with advanced disease. If the CEA level is elevated preoperatively and becomes normal after surgery, it can be used in follow-up evaluations like in colonic cancer.
4. The stool test for occult blood is frequently positive, and melena occurs occasionally.
Staging of stomach cancer TNM
TX: The primary tumor cannot be evaluated.
T0 (T plus zero): There is no evidence of a primary tumor in the stomach.
Tis: This stage describes a condition called carcinoma (cancer) in situ. The cancer is found only in cells on the surface of the inner lining of the stomach called the epithelium and has not spread to any other layers of the stomach.
T1: The tumor has grown into the lamina propria, muscularis mucosae, or the submucosa, which are the inner layers of the wall of the stomach.
- T1a: The tumor has grown into the lamina propria or muscularis mucosae.
- T1b: The tumor has grown into the submucosa.
T2: The tumor has grown into the muscularis propria, the muscle layer of the stomach.
T3: The tumor has grown through all of the layers of the muscle into the connective tissue outside the stomach. It has not grown into the lining of the abdomen, called the peritoneal lining, or into the serosa.
T4: The tumor has grown through all of the layers of the muscle into the connective tissue outside the stomach. It has also grown into the peritoneal lining or serosa or the organs surrounding the stomach.
- T4a: The tumor has grown into the serosa.
- T4b: The tumor has grown into organs surrounding the stomach.
The “N” stands for lymph nodes. Lymph nodes inside the abdomen are called regional lymph nodes.
NX: Regional lymph nodes can't be evaluated.
N0 (N plus zero): cancer has not spread to the regional lymph nodes.
N1: Cancer has spread to 1 to 2 regional lymph nodes.
N2: Cancer has spread to 3 to 6 regional lymph nodes.
N3: Cancer has spread to 7 or more regional lymph nodes.
- N3a: cancer has spread to 7 to 15 regional lymph nodes.
- N3b: cancer has spread to 16 or more regional lymph nodes.
MX: Distant metastasis cannot be evaluated.
M0 (M plus zero): cancer has not spread to other parts of the body.
M1: Cancer has spread to another part or parts of the body.
Management of stomach cancer
Gastrectomy is done in early disease. Mucosal resection at endoscopy use of Lugol's iodine plus wide excision confined to <2cm. It is enhanced by a cold knife which is Lazer tipped knife for resecting tumors.
Also used for invasive tumors confined to the stomach.
The issues are:
a)The extent of gastric resection
b)The extent of lymph node resection.
c)The extent of gastric resection
Adequate gastrectomy implies surgical margins in the stomach free of tumor.
Billroth surgery with Gastrojejunostomy. This is done when a tumour is distal. Adequate resection margins in the stomach are defined as an 8- to 10-cm proximal and distal clearance in the unstretched stomach.
Failure to resect the stomach widely with microscopic clear margins is highly detrimental to survival. If the resection margin is not confirmed to be free of microscopic disease
Proximal tumors-cardia and fundal tumors necessitate total gastrectomy. This carries a lower risk of recurrence or a second gastric cancer in long-term survivors.
Total gastrectomy with a Roux-en-Y esophagojejunostomy to prevent alkaline reflux. The preferred method of reconstruction after total gastrectomy is as a Roux-en-Y with a 60-cm Roux to prevent bile reflux.
Gastric cancer at the cardia the tumor may infiltrate the lower esophagus, and a 10-cm oesophageal clearance is advised to be certain of clear resection margins. Thus surgery involves principles of gastric as well as oesophageal surgery, and in certain respects, it should be regarded as a separate entity.
Extent of lymphadenectomy
R0 gastrectomy does not remove any lymph node group,
R1 gastrectomy removes those nodes in group I (N1), which are predominantly perigastric lymph nodes, but leaves a large portion of the greater omentum. Nodes along the lesser curvature, greater curvature, sub-pyloric nodes,
R2 gastrectomy carries the same criteria for adequate gastric removal but includes lymphadenectomy to remove Group II (N2) nodes en bloc with the stomach.
In general, the entire greater omentum is removed, with the superior leaf of the transverse mesocolon, pancreatic capsule, and lesser omentum.
Lymph node dissection starts by removing the nodes along the gastroduodenal artery to its origin at the hepatic and is continued laterally to the porta hepatitis along the common hepatic artery. The nodes are cleared medially along the common hepatic artery to the coeliac axis which is cleared and continued along the splenic artery to the hilum of the spleen. Supra pancreatic and retropancreatic nodes and nodes along porta-hepatis
R3 gastrectomy attempts to remove nodes in Group III (N3) and involves pancreatic and splenic resection. Nodes involved include those along IVC and Aorta
A palliative operation to relieve gastric outlet obstruction for unresectable tumors.
1. Billroth II -Resection of the distal stomach, closing the transected duodenum and stomach and restoring continuity by a gastrojejunostomy to the posterior wall of the stomach
3.Stents in gastroesophageal junction
Non-operative palliation, including laser therapy and intubation for dysphagia, and interstitial laser therapy for bleeding gastric cancers.
Gastric adenocarcinoma has generally been regarded as radioresistant and, although it is less sensitive than squamous cell carcinoma, useful response and tumor shrinkage has been achieved in patients given palliative radiotherapy for malignant dysphagia.
The major limitation to radiotherapy has been the problem of achieving a dose that will spare adjacent normal tissue, including the liver and the small intestine
Gastrointestinal cancers are generally unresponsive to chemotherapy, but stomach cancer appear to be more sensitive than most and in particular, respond better than colorectal cancer.
Despite evidence to suggest that combined chemotherapy is better, most studies have been performed with single agents. Mitomycin C, doxorubicin, 5-fluorouracil, and nitrosoureas will produce tumor shrinkage in up to 30 percent of patients with advanced disease.
The combination of 5-fluorouracil, doxorubicin, and mitomycin C at present represents the most effective regimen for advanced gastric cancer
1.Carcinoembryonic antigen assay to detect recurrence of the tumour
2. Follow endoscopies if mucosal resection at endoscopy.
Prevention of stomach cancer
1.Tripple therapy to eradicate H.pylori
2. Good nutrition-Vitamins C, E, A intake.
3. Endoscopy in strong family history or patients post-gastrectomy.