GI - Gastric cancer, Esophageal cancer, GIST Flashcards
Gastric Cancer
- Most common histological subtypes
- Distribution in location
- Mode of spread
Histology:
- Adenocarcinoma (95%) - Lauren’s classification into Intestinal, Diffuse, Mixed subtypes
- Gastric neuroendocrine tumours from ECL cells
- Gastric MALT lymphoma
- GIST
- Linitis Plastica
Distribution in location:
Proximal (30%), Middle (30%), Distal (40%)
Recent proximal migration of tumours
Mode of spread:
- Haematogenous: Liver, lung
- Direct: Upper GI organs, Colon, Kidneys and adrenals, Diaphragm
- Lymphatic spread: Peri-gastric - Celiac axis - Para-aortic LN
- Trancoelomic spread: Peritoneal carcinomatosis, Sister Mary Joseph Nodule, Krukenberg’s tumor, Blumer’s shelf
Linitis plastica
- Pathology
- Diagnosis
- Prognosis
Poorly-differentiated diffuse type gastric cancer
Diagnosis:
- Difficult insufflation on OGD (sign)
- Strip and bite biopsy technique (not superficial mucosal biopsy) on OGD
- Cross-sectional imaging by CT abdomen
Prognosis:
- Poor, presents late
- 1/3 with early metastasis to peritoneum/ malignant ascites
- Microscopic disease at surgical margins
Gastric cancer risk factors
Non-modifiable:
- Old age, Male sex, Asian ethnicity
Disease:
- Gastric ulcers
- Atrophic gastritis
- Adenomatous polyps
- Biliary reflux causing intestinal metaplasia
- Menetrier’s disease (protein-losing hypertrophic gastropathy)
Family history:
- Gastric cancer
- Hereditary diffuse gastric cancer (E-cadherin mutation)
- FAP, HNPCC (Lynch syndrome)
Modifiable risk factors:
- Diet: nitrates, nitrosamine in pickled food, smoked and salted food, Low selenium/ Vit C/ fruits and vegetables
- Social: Smoking, Alcoholism, Low socio-economic status, obesity
- Surgical: previous partial gastrectomy or GJ causing long-term biliary reflux and chronic gastritis
Blood and nerve supply of stomach
Arterial:
- Greater curvature: Short gastric a., Left and right gastro-omental/ gastro-epiploic a.
- Lesser curvature: Left and right gastric a.
Venous: SMV
Nerve:
- Sympathetic: Greater splanchnic nerve from T5-9
- Parasympathetic: Anterior Vagus for stomach, pylorus and liver; Posterior Vagus for Stomach, Foregut and midgut down to splenic flexure of colon
Gastric Polyps
- Types
- Respective malignant potential
- Management
Types:
- Adenomatous (premalignant): >2cm correlate with 24% incidence of malignancy. Associated with FAP correlate with 10x incidence of malignancy
- Fundic gland polyp (not pre-malignant/ no malignant potential): a/w long-term PPI use
- Hyperplastic polyp(Minimal malignant potential): Most common type, large polyp >2cm correlates with dysplasia, CIS and gastric cancer development
- Inflammatory polyp (no malignant potential)
- Hamartomatous polyp (no malignant potential)
Management:
- ALL polyps >1cm removed by polypectomy via OGD
- Polyp sample sent to confirm histological diagnosis
- Surgical resection with 2-3cm margin performed laparoscopically or endoscopically if excision by OGD is impossible
Gastric cancer
TNM staging
Tumour may penetrate muscularis propria with extension into the gastrocolic or gastrohepatic ligaments, or into the greater or lesser omentum, without perforation of the visceral peritoneum covering these structures = Classified as T3
Tumour that has perforation of visceral peritoneum covering the gastric ligaments or the omentum = Classified as T4
Adjacent structures of stomach include the spleen, transverse colon, liver, diaphragm, pancreas, abdominal wall, adrenal gland, kidney, small intestine and retroperitoneum
Intramural extension to duodenum or esophagus is NOT considered invasion of adjacent structure but is classified using the depth of the greatest invasion in any of these sites
Classification system for EGJ and gastric cardia cancers
AJCC/ UICC TNM staging
* Tumors involving the EGJ with the tumor epicenter no more than 2 cm into the proximal
stomach are staged as esophageal cancer
* EGJ tumors with their epicenter located more than 2 cm into the proximal stomach are staged as stomach cancer
Siewert classification:
Type I = Located between 5 and 1 cm proximal to anatomical Z-line
- Adenocarcinoma of distal esophagus/ Barrett’s esophagus infiltrating EGJ
- Treatment = Transthoracic en bloc esophagectomy + Partial gastrectomy + 2-
field lymphadenectomy
Type II = Located between 1 cm proximal and 2 cm distal to the anatomical Z-line
- True gastic cardia cancer
- Treatment = Transabdominal/ Transhiatal resection of the distal esophagus + Total gastrectomy + Lymphadenectomy of the lower mediastinum and the abdominal D2 nodal compartment
Type III = Located between 2 and 5 cm distal to anatomical Z-line
- Subcardial gastric cancer infiltrates EGJ
- Treatment = Transabdominal/ Transhiatal resection of the distal esophagus + Total gastrectomy + Lymphadenectomy of the lower mediastinum and the abdominal D2 nodal compartment
Gastric cancer
Macroscopic classification
Borrmann’s classification:
- Type 1 polypoid
- Type 2 fungating
- Type 3 ulcerated
- Type 4 diffusely infiltrative
Japanese Society for Gastroenterological Endoscopu (JSGE)
- Type 1 Polypoid: Pedunculated, Subpendunculated, Sessile
- Type 2 flat: superficial elevated, flat, flat depressed
- Type 3 ulcerated
- Type 4 lateral spreading tumour
Gastric cancer
Histological classification
Adenocarcinoma - Lauren classification
1. Intestinal type: Well-differentiated, less aggressive, predeliction to haematogenous spread, sequalae of H. pylori induced atrophic gastritis and intestinal metaplasia
2. Diffuse type: Undifferentiated, aggressive with poor prognosis, transmural and lympatic spread likely, Signet ring cells with intracellular mucin
Non-AD gastric cancer:
- Carcinoid tumours (ECL cells): Zollinger-Ellison syndrome; MEN1 syndrome
- Gastric MALT lymphoma: H. pylori chronic gastritis
- GIST: c-KIT (most) or PDGFRA gene mutation
Gastric cancer
Clinical features
S/S:
- Epigastric pain
- Dysphagia: proximal gastric cancer
- Early satiety: proximal gastric cancer, GOO
- Nausea/ Vomiting + Succussion splash: GOO from distal gastric cancer
- Haematemesis or tarry stool +/- anaemia: Chronic GIB with IDA
- Constitutional symptoms: anorexia and weight loss, cachexia
- Malignant gastrocolic fistula: colonic obstruction, feculent emesis, passage of undigested food in stool
Metastatic S/S:
- Dyspnea: Lymphangitis carcinomatosis
- Jaundice, hepatomegaly: Liver met
- Abdominal distension: Malignant ascites
- Lymphadenopathy: Left supraclavicular adenopathy (Virchow’s node), Left axillary node (Irish node), Periumbilical node (Sister Mary Joseph’s node)
- Blumer’s shelf, Krukenberg tumour
Gastric cancer
Compare early, intermediate and late symptoms
Paraneoplastic syndromes
Seborrheic keratosis (Leser-Trelat sign)
Acanthosis nigricans
* Hyperpigmentation of axilla and groin
Hypercoagulability
* Migratory superficial thrombophlebitis (Trousseau’s syndrome)
* Deep vein thrombosis (DVT)
Gastric cancer
Investigations
Biochemical:
- CBC with differential: McHc anaemia from IDA
- Clotting profile
- RFT with electrolytes: Membranous nephropathy (paraneoplastic nephrotic syndrome) + assess metabolic alkalosis if severe vomiting due to GOO
- LFT: liver met, biliary obstruction, nutritional status
- Tumour marker: treatment response and prognostic marker only
Imaging:
- Oesophago-gastro-duodenoscopy (OGD) + Biopsy: Histological diagnosis
- (Double-contrast barium meal: for linitis plastica/ infiltrating lesion only)
T/N staging:
- Endoscopic ultrasound (EUS): T/N staging for depth of invasion, perigastric and celiac LN staging
M staging:
- CT throax, abdomen, pelvis (CT T+A+P): M staging for distant metastasis, distal nodal spread and malignant ascites
- PET-CT scan: M staging and confirm CT-detected lymphadenopathy
- Staging laparoscopy + peritoneal cytology: M staging for EUS stage T3/4, detection of small volume liver and peritoneal metastasis
- CXR: M staging for Pleural effusion, Lymphagitis carcinomatosis
Gastric cancer
Treatment options
Palliation:
Bleeding:
- Transcatheter embolization
- External beam radiotherapy (EBRT)
- Palliative gastrectomy
Gastric outlet obstruction
- Endoscopic laser ablation
- Endoscopic self-expanding metallic stent placement
- Palliative gastrectomy
- Palliative bypass with gastrojejunostomy
Medical:
Neoadjuvant chemotherapy: 5-Fluorouracil (5-FU) + Epirubicin + Cisplatin
- Indicated in T3 (transmural) tumours or N1 tumours (LN involvement)
Adjuvant chemotherapy: 5-Fluorouracil (5-FU)/ Leucovorin + Radiation therapy
- Indicated for ALL patients EXCEPT T1-2, N0,M0
Endoscopic treatment:
- Endoscopic mucosal resection (EMR) / Endoscopic submucosal dissection (ESD en bloc resection)
- Indicated for tumour <2cm, LN negative, confined to mucosa on EUS exam
Surgery:
- Gastrectomy + Lymphadenectomy + reconstruction
- Indicated for M0, No major vascular invasion
Gastric cancer surgical treatment
Indicators of unresectability
Extent of gastrectomy
Extent of lymphadenectomy
Unresectable:
- Presence of distant metastasis
- Invasion of major vascular structure including aorta
- Encasement or occlusion of hepatic artery, celiac axis or proximal splenic artery
Extent of gastrectomy:
- Gross negative margin ≥ 5 cm
- En bloc resection of adjacent involved organs such as distal pancreas, transverse colon or spleen is indicated in T4 tumours
Different extent of lymphadenectomy
- D1 lymphadenectomy = Perigastric LNs dissection
- D2 lymphadenectomy (STANDARD) = D1 + Removal of LNs along celiac trunk, common hepatic, splenic, left gastric arteries and those LNs in splenic hilum
- D3 lymphadenectomy = D2 + Removal of LNs in porta hepatis and periaortic regions
STANDARD D2 lymphadenectomy: removes 15 LNs: improves disease-specific survival, accurate N staging, minimize stage migration
Gastric Cancer
Types of gastrectomy and indications
Components resected
Advantages
Proximal tumours (e.g. EGJ/ Cardia tumour) = Total gastrectomy
Midbody tumours = Total gastrectomy
Distal tumours = Subtotal gastrectomy (decreased surigcal complication, improve nutritional and QoL)
Gastric cancer
Gastrointestinal reconstruction
- Types
- Indications
- Specific side effects
Billroth I:
- End-to-end gastroduodenostomy
- Indication: Proximal gastric remnant and duodenal stump can be joined without tension after antrectomy
- Preserve duodenum and jejunum
- S/E: Bile reflux gastritis/ Alkaline gastritis, Dumping syndrome
Billroth II:
- End-to-side gastrojejunostomy
- Indication: Billroth I not possible, like extended distal gastrectomy
- Preserve jejunum
- S/E: Malabsorption, Bile reflux gastritis, Dumping syndrome, Afferent/ Efferent loop syndrome
Roux-en-Y:
- Esophagojejunostomy/ Gastrojejunostomy
+ Jejunojejunostomy
- Indication: Billroth I not possible, like very extended distal gastrectomy; or better QoL
- No structure preserved
- S/E: Malabsorption, (NO bile reflux because of diversion), Dumping syndrome, Roux Stasis Syndrome
GIST
TNM staging
GIST
Treatment options
Targeted therapy
- Tyrosine kinase inhibitor (TKI): Imatinib/ Sunitinib
- Neoadjuvant imatinib: upper GIT or distal rectal GIST; increase resectability
- Adjuvant imatinib: high risk relapse/ GIST > 3cm in size
- Palliative imatinib: metastatic GIST
Surgical resection:
- Exploration by laparatomy
- Indicated for all GIST ≥ 2 cm
- GIST < 1 cm can be follow-up conservatively
- No need for LN dissection
Esophagus
Anatomical divisions
Characteristics of esophagus
* Esophagus is a muscular tube that is 25 cm in length
* Begins at cricoid cartilage (at level C6) to stomach (at level T10)
* Upper esophageal sphincter (UES) is formed by cricopharyngeus muscle
* Lower esophageal sphincter (LES) is NOT an anatomical sphincter but physiological
Histological features of esophagus
* Outer longitudinal and inner circular layer
* Lined by non-keratinizing stratified squamous epithelium
Neurovascular supply of esophagus
Esophageal cancer
TNM staging
Esophageal cancer
Anatomical classification for OGJ/ proximal stomach cancer
AJCC/ UICC TNM staging
* Tumors involving the EGJ with the tumor epicenter no more than 2 cm into the proximal
stomach are staged as esophageal cancer
* EGJ tumors with their epicenter located more than 2 cm into the proximal stomach are staged as stomach cancer
Siewert classification:
Type I = Located between 5 and 1 cm proximal to anatomical Z-line
- Adenocarcinoma of distal esophagus/ Barrett’s esophagus infiltrating EGJ
- Treatment = Transthoracic en bloc esophagectomy + Partial gastrectomy + 2-
field lymphadenectomy
Type II = Located between 1 cm proximal and 2 cm distal to the anatomical Z-line
- True gastic cardia cancer
- Treatment = Transabdominal/ Transhiatal resection of the distal esophagus + Total gastrectomy + Lymphadenectomy of the lower mediastinum and the abdominal D2 nodal compartment
Type III = Located between 2 and 5 cm distal to anatomical Z-line
- Subcardial gastric cancer infiltrates EGJ
- Treatment = Transabdominal/ Transhiatal resection of the distal esophagus + Total gastrectomy + Lymphadenectomy of the lower mediastinum and the abdominal D2 nodal compartment
Esophagectomy
Post-op prevention of complications
