incidence, prognosis and treatment of cancer

Question 1

What are the 4 most common cancers in the uk?

Answer 1

breast, lung, prostate and bowel

Question 2

What are the most common cancers in children under the age of 14?

Answer 2

• leukaemia’s
• CNS tumours
• lymphomas

Question 3

Which cancers carry a very good 5 yr survival rate?

Answer 3

• testicular
• melanoma
• breast
• prostate

Question 4

Which cancers carry a very bad 5 yr survival rate?

Answer 4

• pancreatic
• lung
• oesophageal

Question 5

What factors must be considered when trying to predict the outcome of a cancer?

Answer 5

• age
• general health
• tumour site
• tumour type
• grade (differentiation)
• stage (size/ spread)
• availability of effective treatments

Question 6

What is the common system for assessing tumour burden?

Answer 6

TNM staging (T= size of primary tumour, N= regional spread via lymph nodes, M= distant metastatic spread via blood)

Question 7

Explain how scored are given for each section of the TNM staging system?

Answer 7

T is by size (1,2,3,4)- but it varies
N0 = no lymph spread, N1= regional spread to one lymph node, N2= spread to many nearby lymph nodes
M0= no distant metastasis, M1= distant metasis present

Question 8

Explain the staging of tumours as I, II, III, IV

Answer 8

I= early local disease
II= advanced local disease (N0, M0) 
III= regional metastasis (N1 or more with M0) 
IV= advanced with distant metastasis (M1)

Question 9

What special system is used to stage non-solid lymphomas?

Answer 9

Ann Arbor staging

Question 10

How does Ann Arbor staging work? (for non-solid lymphomas)

Answer 10

I= single lymph node
II= 2 or more lymph nodes effected but on same side of diaphragm
III=lymph nodes on both sides of diaphragm affected
IV= involvement of one or more extra lymphatic organs such as bone marrow or lung

Question 11

What system is used to stage colorectal carcinoma?

Answer 11

Dukes staging

Question 12

How does Dukes staging work? (for bowel cancer)

Answer 12

A= invasion into but not through bowel 
B= invasion through cell wall
C= involvement of lymph nodes 
D= distant metastasis

Question 13

What is grading? Describe the system used

Answer 13

- how well differentiated the cancer is 
G1= well differentiated 
G2= moderately diff
G3= poorly diff 
G4= anaplastic/undifferentiated

Question 14

What ways can cancer be treated?

Answer 14

1. chemotherapy
2. radiotherapy
3. surgery
4. hormone therapy
5. targeted molecular adaptations

Question 15

What is meant by adjuvant and neoadjuvant therapy?

Answer 15

adjuvant: treatment given after surgery to eliminate subclinical micrometastasis
neoadjuvant: treatment given to reduce the size of the primary tumour prior to surgery

Question 16

Describe how radiotherapy is given and how it works (4)

Answer 16

• given in fractioned doses to allow time for healthy cells to recover/minimise normal tissue damage
• causes direct or free radical damage to DNA
• especially in cells in G2 phase (therefor targets rapidly dividing tissues more)
• DNA damage such as DS breaks induces apoptosis as dose is so high that lots of damage cannot be repaired

Question 17

What types of chemotheraputic agents are there? (4)

Answer 17

• Antimetabolites: analogues of normal substances eg fluorouracil inhibits DNA replication as replaces thymine
• Alkylating agents: cross link DNA (cisplatin)
• Antibiotics: many ways- inhibits DNA synthesis mainly (doxorubicin)
• Plant derived drugs block microtubule assembly and interfere with spindle formation (vincristine)

Question 18

Give an example of a hormone therapy targeting cancers

Answer 18

• tamoxifen (SERM) binds to oestrogen receptors preventing oestrogen binding so treats oestrogen receptor positive breast cancer
• androgen blockades can treat some prostate cancers

Question 19

What is the benefit of hormone therapy?

Answer 19

• non toxic as very selective to cancer cells

Question 20

Give 2 examples of oncogenes being targeted to treat cancer

Answer 20

• Herceptin/ trastuzumab blocks HER2 receptor so no inactivates oncogene
• Gleevac/imantinib prevents fusion of two proteins in chronic myeloid leukaemia which cause creates an oncogene

Question 21

Give an example of a hormone tumour marker

Answer 21

human chorionic gonadotrophin released from testicular tumours - measured for diagnosis

Question 22

How are tumour markers useful?

Answer 22

• can sometimes be used for diagnosis (although not specific or sensitive enough really)
• mainly used for monitoring tumour burden

Question 23

What is the limitations of screening programs

Answer 23

• pick up before would even be a problem (lead time bias) so looks like longer 5 yr survival but really isn’t
• pick up people whos are so slow growing they’d never be a problem (over-diagnosis)
• pick up slow growing ones more commonly than fast growing (length time bias)

Question 24

Who are screening programmes meant for?

Answer 24

Healthy people with no symptoms in order to detect cancers as early as possible when chance of cure is highest.

Question 25

What screening programmes are available in the UK?

Answer 25

1) breast screening - women 47-73 YO
2) Cervical screening - women 25-64 YO
3) Bowel screening - men + women 60-74 YO