Colorectal/Bowel Cancer Flashcards
What is colorectal cancer?
Colorectal cancer is a disease in which cells in the colon or rectum grow out of control
- the colon is the large intestine or large bowel
- the rectum is the passageway that connects the colon to the anus.
What are the risk factors for colorectal cancer?
obesity
lifestyle - diet, exercise, smoking and alcohol consumption
type 2 diabetes
age > 50
longstanding inflammatory bowel disease - Crohn’s or ulcerative colitis
family history of bowel cancer
history of non-cancerous growths (polyps) in the bowel
inherited syndromes linked with colorectal cancers - Lynch syndrome and familial adenomatous polyposis
What are preventative measures that can be taken for colorectal cancer?
limit the amount of red meat eaten
- 500g or less per week
avoid processed meat
eat plenty of fibre
- wholegrain, pulses, vegetables and fruit
be a healthy body weight
increasing physical activity, avoiding tobacco and limiting alcohol consumption
takin aspirin
What are the signs and symptoms of colorectal cancer?
changes in bowel habits - diarrhoea, constipation lasting more than a few days
rectal bleeding - bright red blood
blood in stools - stools look dark brown or black
cramping or abdominal pain
weakness and fatigue
unintentional weight loss
feeling that the bowel doesn’t empty all the way during a bowel movement.
How can colorectal cancer be screened for?
home test kit called the faecal immunochemical test (FIT)
- small amount of poo is tested for blood
if positive a colonoscopy is conducted
available to everyone aged 60 to 74 years.
How can colorectal cancer be diagnosed?
medical history and physical examination
faecal immunochemical test (FIT)
blood tests - haematology and biochemistry test, tumour markers
diagnostic colonoscopy
proctoscopy - if rectan cancer is suspected
biopsy which includes gene tests - KRAS, NRAS, BRAF genes
What imaging tests are used to diagnose colorectal cancer?
Computer tomography (CT or CAT scan)
Ultrasound- abdominal, endorectal, intraoperative
Magnetic resonance imaging (MRI) scan
Positron emission tomography (PET) scan
Angiography
What are the stages of colorectal cancer?
Stage 0 - cancer cells on the surface of the rectal lining (mucosa), sometimes within a polyp
Stage 1 - tumour extending below the rectal mucosa, sometimes penetrating into the rectal wall
Stage 2 - tumour extending into or through the rectal wall, sometimes reaching and growing on or sticking to tissues next to the rectum
Stage 3 - tumour invading lymph nodes next to the rectum as well as structures and tissues outside the rectal wall
Stage 4 - tumour spread to a distant organ or lymph nodes distant to the rectum
What are the different treatment options for colorectal cancer?
surgery
radiation
chemotherapy
targeted therapy
What are the most common types of surgery for colorectal cancer?
Right hemicolectomy - removal of the right part of the colon
Sigmoid colectomy - removal of the sigmoid colon (terminal portion prior to the rectum)
Left hemicolectomy - removal of the left part of the colon
Low anterior resection (LAR) - removal of the transverse colon (longest part of the colon)
What are the types of chemotherapy for colorectal cancer?
adjuvant chemo - is given AFTER surgery to kill cancerous cells left after surgery
neoadjuvant chemo - is given BEFORE surgery to try to shrink the cancer and make it easier to remove
What drugs are given for adjuvant treatment of colorectal cancer?
5-fluorouracil (5FU)
capecitabine
oxaliplatin
What is the mechanism of action of 5-fluorouracil (5FU)?
it is an anti-metabolite drug
- inhibits thymidylate synthase (TS) and incorporation of its metabolites into RNA and DNA thereby inhibiting their synthesis
What are the side effects of 5-fluorouracil?
increased risk of infection
bruising and bleeding
anaemia
sore throat and mouth
hair loss
diarrhoea
fatigue
palmar-plantar (hand-foot syndrome) - soreness, redness, and blistering of palms of the hands and soles of feet
heart failure/heart attack (low risk)
What is the mechanism of action of capecitabine?
Capecitabine is a pro-drug of fluorouracil
- it acts as a pyrimidine antimetabolite
- inhibits thymidylate synthase thereby interferes with DNA synthesis
is tumour selective (mainly activated in the liver and tumours)
What are the side effects of capecitabine?
increased risk of infection
bruising and bleeding
anaemia
sore throat and mouth
hair loss
diarrhoea
fatigue
palmar-plantar (hand-foot syndrome) - soreness, redness, and blistering of palms of the hands and soles of feet
heart failure/heart attack (low risk)
What is the mechanism of action of oxaliplatin?
Forms cross-linking-adducts (intra and interstrand cross linking), thus blocking DNA replication and transcription
Combination with leucovorin and 5-FU significantly improves response rates
What are the side effects of oxaliplatin?
myelosuppression - decrease in the ability of the bone marrow to produce blood cells (anaemia, leukopenia or thrombocytopenia)
sensitivity to cold
numbness/tingling in hands and feet
laryngopharyngeal dysesthesia - uncomfortable persistent sensation in the area of the laryngopharynx
hypersensitivity/allergic reactions
nausea and vomiting
What is the mechanism of action of irinotecan?
- used for metastatic colorectal cancer
inhibits topoisomerase I and prevents religation of the DNA strand
- impedes DNA uncoiling leading to double stranded DNA breaks
is administered with capecitabine or 5FU
- CAPIRI OR FOLFIRI regimens
What are the side effects of irinotecan?
Myelosuppression - decrease in the ability of the bone marrow to produce blood cells (anaemia, leukopenia or thrombocytopenia)
Diarrhoea - early and late onset
Hair loss - alopecia
Loss of appetite
Nausea / vomiting
