Colorectal Cancer

Question 1

What is qFIT?

Answer 1

The Quantitative Faecal ImmunochemicalTest(qFIT) is atestto detect hidden or ‘occult’ blood in stool samples.
-qFIT testuses antibodies that specifically recognise human haemoglobin and are consequently more sensitive and specifictestthan the guaiac based FOBtest.

Question 2

Describe a colonoscopy

Answer 2

• Optic fiber= high magnification image
• Up rectum
• Can perform therapeutics

Question 3

Describe the appearance of a polyp

Answer 3

• Polypoid lesion on a stalk, projecting into the lumen of the colon
• Smooth surface
• Well circumscribed
• No obvious ulceration or haemorrhage

Question 4

What could be the microscopic features of a polyp?

Answer 4

• Dysplastic glands forming tubular and villous structures – adenoma
• Abnormal glands invading the wall of the colon with a stromal reaction – adenocarcinoma

Question 5

What are the cytological features of malignancy?

Answer 5

• High nucleus/cytoplasm ratio
• Hyperchromasia
• Pleomorphism

Question 6

What is the clinical implications of adenocarcinoma observation?

Answer 6

• The adenoma has progressed to form an adenocarcinoma, which is invading the base of the polyp.
• The patient should be staged with CT scan or MRI scan and discussed at an appropriate multidisciplinary meeting involving pathologists, radiologists and surgeons to determine the next steps.
• Definitive surgery should be considered.

Question 7

Describe colonic polyps

Answer 7

• Not all colonic polyps progress to adenocarcinoma
• Adenomas have the highest progression potential to adenocarcinoma
• Hyperplastic ( metaplastic) polyps don’t have malignant potential
• A special type of hyperplastic polyp called serrated polyp has some malignant potential.

Question 8

What is the adenoma-carcinoma sequence?

Answer 8

Theadenoma-carcinoma sequencerefers to a stepwise pattern of mutational activation of oncogenes (e.g.K-ras) and inactivation oftumour suppressor genes(e.g.p53) that results in cancer.

Question 9

What is an oncogene?

Answer 9

Anoncogeneis a gene that has the potential to cause cancer. In tumour cells, these are often mutated or expressed at high levels.

Question 10

What is a tumour suppressor gene?

Answer 10

A tumour suppressor gene is a gene that is involved in dampening the cell cycle or promotion of apoptosis or both. Examples include inactivation ofp53.

Question 11

What is the APC protein?

Answer 11

TheAPCprotein ( tumour suppressor) isencoded by theAPC genea negative regulator that controls beta-catenin concentrations and interacts with E-cadherin, whichareinvolved in cell adhesion. Deletion of the APC gene predisposes to cancer.

Question 12

What are the alarm features for colorectal cancer?

Answer 12

• Weight loss
• Rectal bleeding
• Anaemia, thrombocytosis
• Persistent diarrhoea (lack of day-day variability) in R side colon cancers ( ascending colon and caecal tumours)
• Frequent nocturnal symptoms
• New onset over 50 yrs
• FHx bowel cancer/
• PMHx IBD

Question 13

What is the possible diagnosis for rectal bleeding and mild anaemia?

Answer 13

• Haemorrhoids
• Colon polyps
• Colon cancer
• Inflammatory bowel disease (normally diarrhoea, young people)

Question 14

What is the grade of a tumour?

Answer 14

The grade of a cancer is based on how the patterns of cancer cells look under a microscope: normal (or differentiated) or abnormal. Higher grade tumors tend to grow and spread faster than lower grade tumors.

Question 15

What is the stage of a tumour?

Answer 15

The stage of colorectal cancer is a standard way for doctors to sum up how far the cancer has spread.

Question 16

Describe the TNM staging system

Answer 16

• T refers to how far the primary tumor has grown into the wall of the esophagus and into nearby organs.
• N refers to cancer spread to nearby lymph nodes.
• M indicates whether the cancer has metastasized (spread to distant organs).

Question 17

What are the T stages and their relation to the lining?

Answer 17

• T1= mucosa/ submucosa
• T2= muscularis
• T3= serosa
• T4= nearby organs

Question 18

What is the treatment for T2N1 tumour?

Answer 18

• Surgery
• Pathology showed early colonic adenocarcinoma (T2) with 2 lymph nodes involved T2N1
• Alternative classification Dukes staging (A-D) ( now replaced by TNM )
• Following surgery patient received also chemotherapy with good effect.

Question 19

What are the risk factors for colorectal cancer?

Answer 19

• A diet high in redmeatsand processedmeats raises colorectal cancer risk.
• Cookingmeatsat very high temperatures (frying, broiling, or grilling) creates chemicals that might raise cancer risk.
• Diet low in fibre
• Obesity.
• Physical inactivity.
• Smoking.Alcohol excess.
• A family history of colorectalpolypsor colorectal cancer.
• History ofinflammatory bowel disease.
• Older age

Question 20

Describe the distribution of colorectal cancer per anatomical site

Answer 20

-Majority in rectum (32 M/ 23 F)/ rectosigmoid junction
area (sigmoid 23 M/ 20 F)
-Caecum and ascending colon- females more
-Flexible colonoscopy only examines left side= good for screening

Question 21

Describe colorectal cancer screening

Answer 21

• The prevention of death from colorectal cancer by identifying and treating pre-invasive disease (adenoma) and early invasive adenocarcinoma.
• Population over the age of 50 routinely and regularly checked for occult blood (qFIT)
• If positive they get a colonoscopy
• Removal of adenomas is curative.
• Detection of adenocarcinoma before it has spread to lymph nodes, liver or elsewhere increases the chances of surgical cure.
• Patient survival is strongly linked to the extent of spread of adenocarcinoma (stage)