Colonic Carcinoma Flashcards
1
Q
Histology
A
Adenoma (adenoma-carcinoma)
2
Q
AETIOLOGY
Risk factors
A
- Age
- FH
- Familial adenomatous polyposis (FAP)
- Hereditary nonpolyposis colorectal cancer (HNPCC, also called Lynch syndrome)
- Previous history polyps
- IBD
- Diet (high red meat and low fibre)
- Obesity
- Smoking
- Alcohol
3
Q
AETIOLOGY
Pathophysiology
A
- Adenoma-carcinoma sequence
- Usually double hit deactivation of both APC genes in epithelial cell and then further genetic mutations (including K-ras and p53)
- Polyps increasingly become dysplastic and subsequently invasive
4
Q
CLINICAL FEATURES
Presentation
A
- Signs of iron deficiency anaemia
- Altered bowel habit
- Abdominal pain from partial obstruction
- Bowel obstruction symptoms
- Rectal bleeding
- Symptoms form metastasis
- Jaundice and RUQ pain from hepatic metastasis
- Ascitis or pain from peritoneal metastasis
- Weight loss
5
Q
INVESTIGATIONS
First choice
A
- Conoloscopy - first line and gold standard
- CT chest, abdomen and pelvis to stage
- Bloods
- Carcinoembryonic antigen (CEA) - tumour marker
6
Q
MANAGEMENT
General principles
A
- In stage 1 surgical excision
- Stages 2 to 3 surgical excission followed by adjuvant chemotherapy
- If metastatic (stage 4) surgical resection and most likely palliative therapy with chemotherapy and radiotherapy
7
Q
COMPLICATIONS
A
- Metastais
- Obstruction
- Iron deficiency anaemia
- Bleeding
8
Q
PROGNOSIS
5 year mortality
A
- If stage 1 is very good (90%)
- If stage 4 is only 8%
9
Q
Screening
A
- In Scotland, everyone 50-74 screened every 2 years with faecal immunochemical tests (FIT)
- Looks at human haemoglobin in stool
- Follow up colonoscopy
- People with risk factors like FAP, HNPCC or IBD offered colonoscopy at regular intervals
10
Q
Is FAP dominant or resessive and what genes
A
- Autosomal dominant
- Involves malfunctioning of tumour suppresor genes called adenomatous polyposis coli (APC), causing many polyps (adenomas) in large intestine
11
Q
Is HNPCC dominant or ressesive and what genes
A
- Autosomal dominant
- Results from mutations in DNA mismatch repair (MMR) genes
- Unlike FAP, does not cause adenomas and develops in isolation
12
Q
What is NICE guidelines for suspected cancer recognition and referral
A
- 2 week wait urgent cancer referral
- Over 40 years with abdominal pain and unexplained weight loss
- Over 50 with unexplained rectal bleeding
- Over 60 with change in bowel habit or iron deficiency anaemia
13
Q
What classifcation systems are used
A
- Dukes
- TNM
14
Q
Describe DUKES
A
- Not used anymore, been replaced by TNM
- A - confined to mucosa and part of muscle of bowel wall
- B - extending through the muscle of bowel
- C - lymph node involvement
- D - metastatic disease
15
Q
Describe T for TNM classification
A
- TX - unable to assess size
- T1 - submucosal involvement
- T2 - involvement of muscularis propria (muscle layer)
- T3 - involvement of subserosa and serosa (outer layer) but not through the serosa
- T4 - spread through serosa (4a) reaching other tissues or organs (4b)
