GI cancer: Large bowel cancer

Question 1

Colorectal polyps + cancer precursor

Answer 1

ADENOMA (or POLYP)
- mostly spontaneous and benign
- common with age but can progress to cancers

Question 2

Risk factors

Answer 2

Family history of bowel cancer
Familial adenomatous polyposis (FAP)
Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome
Inflammatory bowel disease (Crohn’s or ulcerative colitis)
Increased age
Diet (high in red and processed meat and low in fibre)
Obesity and sedentary lifestyle
Smoking
Alcohol

Question 3

2 inherited conditions which MASSIVELY increases risk of polyps AUTO DOM

Answer 3

Familial adenomatous polyposis (FAP)
Hereditary nonpolyposis colorectal cancer (HNPCC)

Question 4

Familial adenomatous polyposis (FAP)

Answer 4

Autosomal dominant
malfunctioning of the tumour suppressor genes called adenomatous polyposis coli (APC)
= many polyps
Eventually become cancer (usually before 40)
Preventative = panproctocolectomy

Question 5

Hereditary nonpolyposis colorectal cancer (HNPCC)

Answer 5

Also known as Lynch syndrome
Autosomal dominant = MSH-1 mutation
Mutation in DNA mismatch repair (MMR) genes
Does not cause adenomas and tumours develop in isolation

Question 6

Common metastasis locations

Answer 6

Liver
Lungs

Question 7

Red flag symptoms

Answer 7

Change in bowel habits
Unexplained weight loss
Rectal bleeding
Unexplained abdominal pain
Iron def anaemia
Abdo/rectal mass

Question 8

Symptoms

Answer 8

Distal colon = LLQ pain
Bloody mucusy stools (fresh blood, distal colon close to anus)
Tenesmus (if rectal involvement)

Question 9

Screening

Answer 9

Faecal immunochemical test FIT test (faecal occult) = screening test to see amount of human haemoglobin in stool = 60-74 years old
- People with risk factors such as FAP, HNPCC or inflammatory bowel disease are offered a colonoscopy at regular intervals to screen for bowel cancer.

Question 10

Suspected cancer diagnosis

Answer 10

Suspected cancer pathway referral = 2 week wait
= positive fit test referred to colonoscopy within 2 weeks
GOLD STANDARD = Colonoscopy + biopsy
Staging = CT

Question 11

Classification

Answer 11

TNM classification
TX – unable to assess size
T1 – submucosa involvement
T2 – involvement of muscularis propria (muscle layer)
T3 – involvement of the subserosa and serosa (outer layer), but not through the serosa
T4 – spread through the serosa (4a) reaching other tissues or organs (4b)
N for Nodes:

NX – unable to assess nodes
N0 – no nodal spread
N1 – spread to 1-3 nodes
N2 – spread to more than 3 nodes

M for Metastasis:

M0 – no metastasis
M1 – metastasis

Question 12

Management

Answer 12

Laparoscopic surgery + chemo