Gastrointestinal Cancer Flashcards
What is meant by primary cancer?
arising directly from the cells in an organ
What is meant by secondary cancer?
a metastatic cancer spread to another organ directly or by other means such as blood or lymph
Where does squamous cell carcinoma arise from?
from normal oesophageal squamous epithelium involving the acetaldehyde pathway
Where does adenocarcinoma arise from?
metaplastic columnar epithelium and is related to acid reflux
Outline the progression of reflux to cancer
inflammation from reflux to barretts metaplasia oesophagus to dysplasia to adenocarcinoma
How do we carry out Barretts oesophagus surveillance according to the BSG guidelines?
no dysplasia -> every 2/3 years have endoscopy
with low grade dysplasia -> carry out endoscopy every 6 months
high grade dysplasia -> intervene
What are the clinical signs of oesophageal cancer?
dysphagia and weight loss
How do diagnose gastrointestinal tract cancer?
endoscopy biopsy to determine adenocarcinoma vs squamous cell carcinoma etc
How do we stage gastrointestinal tract cancer?
CT scan
laparoscopy - for metastasises
oesophageal ultrasound
PET scan - to pick up other metastasises
How do we treat adenocarcinoma GI cancer?
neo adjuvant chemotherapy
radical surgery
palliative treatment - chemotherapy, radiotherapy, oesophageal stent
What are the forms of colorectal cancer?
sporadic - no family history
familial - family history of colorectal cancer
hereditary syndrome - family history, younger age of onset, specific gene defects
What are examples of colorectal cancer with a hereditary syndrome?
familial adenomatous polyposis
hereditary non polyposis colorectal cancer
Outline the pathogenesis of colorectal cancer
1 a normal epithelium with an APC mutation
2 leads to a hyperproliferative epithelium with an aberrant cryptic fold resulting in aberrant COX 2 overexpression which results in a small adenoma (polyp)
3 K-ras mutation can lead to the small adenoma forming a large adenoma
4 p53 mutation paired with loss of 18q results in colon carcinoma
How can aspirin, folate and calcium reduce risk of colorectal cancer
- by affecting APC mutation that leads to hyperproliferative endothelium
- aspirin can inhibit COX preventing a small adenoma
- aspirin can inhibit K-ras mutation resulting in reduced risk of large adenoma
What are the risk factors for colorectal cancer?
family history - identified genetic predisposition such as FAP
past history - colorectal cancer, adenoma, ulcerative colitis, radiotherapy
diet/ environmental - ie carcinogenic foods, smoking, obesity, socioeconomic status
How does caecal cancer present clinically?
iron deficiency anaemia
change of bowel habit commonly diarrhoea
distal ileum obstruction
palpable mass
What is the difference between sigmoidscopy and colonoscopy
smaller endoscope only assessing sigmoid colon and rectal cancer
whereas colonscopy assess all of the colon
How does sigmoid carcinoma present?
PR bleeding and more mucus
very thin stool
What are symptoms of rectal carcinoma?
PR bleeding, mucus, anal perineal and sacral pain
tenesmus - feeling that you need to pass stool despite empty bowel
bowel obstruction
What are signs of local invasion?
bladder symptoms
female genital tract symptoms
distal rectal examination
metastasis - liver (jaundice, lung (cough) , regional lymph nodes, sister mary joseph nodule (umbilicus metastatic cancer that is visible)
What are the signs of primary cancer?
abdominal mass
rigid sigmoidscopy
abdominal tenderness and distension
How do we diagnose colorectal cancer?
FBC - showing anaemia and low ferritin
Tumour markers - CEA (but its not diagnostic alone)
guaiac test - to detect fecal occult blood
FIT - faecal immunochemical test which also detects faecal occult blood
How do we investigate colorectal cancer?
colonoscopy under sedation - can visualise lesions less than 5mm
small polyps can be removed to reduce the cancer incidence
or CT colonoscopy/colonography
What is CT colonoscopy/colonography?
less invasive and can visualise lesions greater than 5mm -> if lesions identified patient needs colonoscopy for diagnosis
