GIT Tumours Flashcards
What are the types of tumours?
- benign 2. malignant
Describe the benign type?
- Non-neoplastic or neoplastic 2. No significant morbidity or mortality
Describe the malignant type?
- Cause significant morbidity and mortality 2. Some are associated with familial syndromes e.g. colorectal cancer
Name the benign tumours of the stomach?
- non-neoplastic polyps (most common) 2. neoplastic polyps 3. leimyoma 4. schwannoma
Describe non-neoplastic polyps?
- Hyperplastic polyps (75%): Chronic inflammation 2. Fundic gland polyps: associated with FAP and use of proton pump inhibitors 3. Inflammatory fibroid polyps
Describe neoplastic polyps?
–Adenomas with risk of progressing into cancer
Name the malignant tumours of the stomach?
- Gastrointestinal stromal tumours (GIST) 2. Carcinoid tumours (neuroendocrine) 3. Lymphomas 4. Kaposi’s sarcoma(usually in immunosupression eg HIV in our setting)
What is the most common malignant stomach tumour?
gastric adenocarcinoma
Describe the epidemiology of gastric adenocarcinoma?
- Second most common in the world 2. Common in low socio-economic groups 3. Affects males more than females 4. Not among the top five cancers in Malawi, however we see it in clinical practice: usually advanced forms - All GIT tumours: stomach to anus = 1.6%: 2012 cancer registry statistics
What are the environmental factors associated with gastric adenocarcinoma?
- Infection by H.pylori: chronic gastritis > intestinal metaplasia> dysplasia 2. diet 3. cigarette smoking
Describe how diet is associated with gastric adenocarcinoma?
- Nitrites (preserved food) 2. Smoked, salted food, pickles, chillies 3. Lack of fresh fruit and vegetables
Describe the host factors associated with gastric adenocarcinoma?
- chronic gastritis with : Hypochloridria favours H.pylori colonisation and intestinal metaplasia 2. Partial gastrectomy with billious and alkaline intestinal fluid reflux 3. gastric adenomas
Describe the genetic factors associated with gastric cancer?
- Slightly increased risk with blood group A 2. Family history of gastric cancer 3. Mutations in the Wnt signaling pathways (loss of function in APC gene and gain of function in B-catenin 4. Hereditary non polyposis colorectal syndrome (HNPCC) 5. Familial gastric carcinoma syndrome (E-cadherin mutation)
What is the role of H. Pylori in gastric adenocarcinomas?
- chronic inflammation - There is DNA damage and genomic mutations with the chronic inflammatory state 2. atrophy 3. intestinal metaplasia 4. dysplasia - carcinoma : Infection with H.pylori increases risk by 5 to 6 fold
What are the types of gastric adenocarcinomas?
- intestinal type 2. diffuse type
Describe the intestinal type?
- formation of glandular stuctures 2. H.pylori associated
Describe the diffuse type?
- infiltrative growth as sheets of single cells with no gland formation 2. E-cadherin mutation associated
Describe the clinical presentation of gastric adenocarcinoma?
- abdominal pain 2. upper GIT bleeding 3. anaemia 4. weight loss 5. dyspepsia
Describe the diagnosis?
- Endoscopy to examined the stomach lining 2. biopsy
Describe the mestasteses?
- Spread to regional and distant lymph nodes, adjacent and distant organs 2. Virchow’s node: (spread to a supraclavicular lymph node 3. Sister Mary Joseph nodule: Periumbilical subcutaneous nodule 4. Krukenberg tumour: metastases to ovary usually bilateral
Name benign tumours?
- adenomas 2. lipomas 3. leiomyomas
Name malignant tumours?
- adenocarcinoma 2. carcinoid
Name colorectal polyps?
- hyperplastic polyps 2. hamartomatous polyps - Juvenile polyps and Peutz –Jegers polyp syndrome 3. neoplastic polyps
Describe the epidemiology of colorectal carcinomas?
- Not amongst the top five cancers in Malawi in both men and women 2. Disease of older people, peak 60 yrs
Describe the occurrence of colerectal carcinoma?
- can occur sporaddically or associated with familial syndromes 2. The are distinct genetic alterations associated with development of colorectal carcinoma - Common one is the adenoma-carcinoma sequence
What are the risk factors?
- Low intake of unabsorbable vegetable fibre 2. High content of refined carbohydrates 3. Excess diatery caloric intake 4. Intake of red meat and high fat content in diet 5. Decreased intake of protective micronutrients as a result of refined diets 6. smoking 7. Inflammatory bowel disease: ulcerative colitis
What are the 2 molecular pathways of colorectal carcinoma?
- The Adenomatous polyposis coli (APC)/β catenin pathway 2. Microsatellite instability pathway (DNA mismatch repair genes) - Both pathways exhibit stepwise accumulation of mutations
Describe the APC/β-Catenin Pathway?
- Genetic alterations (mutations) involve - The tumour suppressor genes: APC, p53 2. oncogenes - K-RAS activation 3. There is activation of telomerase: Hence no cellular ageing
Describe the microsatellite instability pathway (DNA mismatch repair genes)?
- Microsatellites are fragments of repeat sequences in the genome 2. Microsatellites are prone to malalignment during replication 3. Malalignment repaired by DNA mismatch repair genes 4. Mutations in DNA mismatch repair genes result in accumulation of mutations in cell growth regulatory proteins
Describe the morphology colorectal carcinoma?
- Commonly arise in rectosigmoid, followed by caecum/ascending colon 2. Single tumour or multiple 3. Polypoid, exophytic masses: proximal colon (eg caecum) 4. Annular, circumferential tumours: common in rectosigmoid 5. Colon cancers are adenocarcinomas
What are the clinical features?
- fatigue + weakness 2. iron deficiency anemia 3. abdominal discomfort/pain 4. Frank blood in stool or malema 5. intestinal obstruction 6. metastases through blood vessels and lymphatics
Name colorectal cancer syndromes?
- Familial adenomatous polyposis syndrome (FAP) 2. Hereditary non-polyposis colorectal cancer (HNPCC)
Describe familial adenomatous polyposis syndrome?
- Mutation in APC gene at 5q21 2. Numerous adenomatous polyps with malignant transformation potential in GIT
Describe Hereditary non-polyposis colorectal cancer (HNPCC)?
- DNA mismatch repair with microsatellite instability 2. Extraintestinal cancer eg endometrium 3. Usually multiple cancers
