Gastric CA - a story of two diseases Flashcards
What are risk factors for gastric CA?
Risk factors
• H Pylori
• Previous gastric surgery
• Pernicious Anemia/ Adenamatous polyps – hypochloremic state
• Chronic atrophic gastritis – predisposes to metaplasia
• Radiation exposure
Features of early GC
Early is confined to the mucosa without lymph node spread.
• Type 1 – polyp no sub mucosal involvement
• Type 2a, 2b, 2c- elvevated, flat, depressed respectively
• Type 3 Excavated /ulcerated
Features of late GC - Borrman classification
Late/Advanced has progressed beyond the mucosa
Type 1 Fungating
Type 2 Ulcerated - raised everted edges with a necrotic base and surrounding mucosal infiltration
Type 3 Ulceratioon with inf
Type 4 infiltration - no lesion- wall of the stomach is invaded by malignancy and this causes a desmotic reaction where the stomah becomes contracted, shortened and hypoperistaltic, lining is plastica type aka leather bottle
Mechanisms of spread?
Direct - through stomach wall, to adjacent organs eg posteriorly may spread to pancreas, from pyloric region distal spread into the duodenum, and proximally in GE junction /esophagus
Lymphatic - lymphatic spread is along named vessels D1 spread - along the epiploic greater/lesser curve D2 is along the right and left gastric short gastric and right and left gastroepiploic
D3 - preaortic group of nodes - celiac
D4 - paraaortic nodes
Hematogenous - by venous emboli usually through the portal system - usually goes to the liver or lung
Transcelomic - spreads through and into the peritoneal cavity. cells break off and implant onto the peritoneal cavity causeing ascites - or spreads onto a fertile ovary and gives mucinous ovarian tumor (krukenburg tumors)
Presentation of gastric cancer
early gastric are asymptomatic
late gastric presents with indigestion nausea/vomiting postprandial fullness loss of appetite melena hematemesis weight loss dysphagia
Physical signs of GC
- Dehydrated
- cachexic and starved
- ascites
- pleural or peritoneal effusion
- jaundice due to liver involvement due to obstruction of hepatic bile duct
- gastric outlet obstruction
- peristaltic waves of the stomach
- succusion splash - when you shake them around its like youre shaking water in a bottle due to retained fluid in the stomach
what electrolyte derangements does pyloric outlet obstruction syndrome cause
when the pyloric outlet is blocked the vomiting which occurs is with a closed pylorus - this vomiting is usually non bilious
gastric juice contains sodium pottasium choride
Hypomatremia, hypochloremia, hypokalemia occurs and body becomes alkalotic and a metabolic alkalosis occurs
Paradoxical aciduria occurs even though the body is alkalotic. This happens because you have lost so much sodium that the kidney is holding on ot all the sodium in the body it can . it does this by exchanging with intracellular pottasium which you pass out in urine, as you get more and more hypokalemic the body can no longer put out pottassium so it puts out hydrogen ions and thats why urine is acidic
What blood investigations are done in advanced GC
- CBC - anemia
- Electrolytes - especially in outlet obstruction syndrome
- Liver Function tests - secondary mets or jaundice
- Tumor markers CEA, CA 19-9 any genetic predispositions and for follow up of the patient later on
What imaging is done in GC?
- Upper GI endoscopy - GOLD STANDARD
- Chest Radiograph - looking for pleural effusions
- Double contrast GI series
- CT MRI
- Endoscopic ultrasound - ultrasound stomach wall from inside the stomach especially in early cancer detection this is especially important as you can see all layers of the stomach and nodes. It also helps determine spread to nodes and adjacent organs.
normally do upperGI endoscopy with endoscopic ultrasound and CT/MRI
Huge J shaped stomach with retention of barium
Indicative of outlet obstruction syndrome
What is perioperative preparation for GC?
- Correction of electrolytes - rehydrate with IV fluid FIRST - N/S - hold off on K replacement initially until they are passing enough urine as if you don’t you can cause a hyperkalemia and kill them. After they are passing enough urine you can correct K.
Pottasium correction 40-60 meq per day in 70kg person - may need up to 100.
- Transfusion
- Cardiopulmonary assessment and optimization
- Pass nasogastric tube
- Stomach lavage - if vomiting wash stomach out with saline as you need a fairly clean stomach to perform the surgery on. we don’t want to spill the stomach contents into the peritoneum when operating
- Antibiotics
- Anticoagulants - thromboembolic prophylaxis
What operation is done in advanced GC?
We dissect based on the nodes which are affected eg. D1, D2, D3 etc
Patients with early gastric cancer treatment options
endoscopic mucosectomy- gel injected to elevate the mucosa and usind diathermy the polyp is resected.
After
Use Proton pump inhibitors and allow them to heal.
What is chromoendoscopy
chromoendoscopy is used for screening in high risk persons by injecting die to see varying appearance of mucosa in stomach
Most common site of gastric cancer
Pyloric region