Intro to oncology

Question 1

What is the definition of cancer?

Answer 1

Pathological hyperplasia resulting from genetic mutation.

Question 2

What are the key genetic mutations in cancer?

Answer 2

Oncogenes
Tumour suppresser genes

Question 3

What are some causes of cancer?

Answer 3

Chemical damage,
Ionising radiation
Viruses - Eg, EBV or HPV

Question 4

What is the definition of malignancy?

Answer 4

Ability to invade local tissues and metastasis

Question 5

What are the red flag symptoms for cancer?

Answer 5

Difficulty breathing/swallowing,
Appetite loss, persistent bloating, fatigue, unusual lump. new mole, unexplained PV bleeding, haematuria, breast changes, croaky voice, mouth or tongue ulcer that lasts more than 3 weeks, change in bowel habit.

Question 6

What is the WHO Performance status

Answer 6

0 - fully active
1 - physically restricted in strenuous activity
2 - Capable to carry out selfcare but no work activities. Up for more than 50% waking hours
3 - Limited selfcare, confined to bed/chair for >50% waking hours.
4 - Completely disabled
5 - dead

Question 7

What are the main targets of chemotherapy?

Answer 7

Attack cell division (explains why side effects occur in systems with dividing cells, eg, hair, GI, immune system)
They do no reverse differentiation, invasion or metastasis

Question 8

What are the general side effects of chemotherapy?

Answer 8

Bone marrow suppression (anaemia, immune depression and impaired wound healing)
Hair loss,
Damage to GI epithelium,
Damage to liver, heart and kidneys,
Depression of growth in children,
Sterility
Cystitis,
Skin changes,
Cardiotoxicity,
Teratogenic

Question 9

What are the main classes of cancer chemotherapy drugs?

Answer 9

Alkylating agents,
Antimetabolites.
Cytotoxic antibodies,
Microtubule inhibitors,
Steroid hormones and antagonists

Question 10

Name the different types of drugs within the alkylating agent group

Answer 10

Nitrogen mustards: Cyclophosphamide,
Platinum based compounds: Cisplatin
Nitrosoureas: Lomustine (active in CNS because it is Lipid soluble)
Alkylsulphonates: Busulphan (Selective for bone marrow)
Other example is temozolomide

Question 11

Name different classes and examples of antimetabolites

Answer 11

Folate antagonists, eg, Methotrexate.
Pyrimidine analogues eg, fluoro-uracil (prevents thymidine formation and stops DNA synthesis)
Purine analogues, eg, Mercaptopurine, fludarabine,

Question 12

Name some examples of cytotoxic antibiotics and their mechanism of action

Answer 12

Dactinomycin: Isolated from Streptomyces. Inserts itself into minor grove at DNA helix, disrupting RNA polymerase function.
Doxorubicin: Also isolated from Streptomyces. It causes local uncoiling and impairs DNA and RNA synthesis. Very effective

Question 13

Name an example of a plant derivative (microtubule inhibitor) and its mechanism of action

Answer 13

Vinca alkaloids eg, vincristine.
It binds to microtubular proteins, blocking tubulin polymerisation and blocks normal spindle formation. Thus disrupting cell division.

Question 14

Name the different steroid hormone used in cancer treatment and how it works?

Answer 14

Predisone which is converted into prednisolone in the body and supresses lymphocyte growth.

Question 15

What are some tumours which can be cured with radiotherapy?

Answer 15

Lung cancers,
Head and neck,
Gynae,
Prostate cancer,
Oesophageal cancer,
Anal cancer

Question 16

What are the side effects of radiotherapy?

Answer 16

Depends on site:
Early (<3 months): Skin erythema, mucositis, dysphagia, fatigue!! (big one), tumour flare
Late (>3months): dry mouth, osteoradionecrosis, lung fibrosis,

Question 17

Describe features of antimetabolits

Answer 17

Eg, 5 fluorouracil or gemcitabine. These are pyrimidine analogues which induces DNA damage.
Uses: GI, urological, H&N, breast and lung.
Side effects: Myelosupression, GI toxicity, mucositis, palmar-planter erythrodysaethesia and cardiotoxicity

Question 18

Describe features of alkylating agents/platinum

Answer 18

Eg, cisplatin, cyclophosphamide. These covalently bind to DNA and inhibit DNA synthesis by forming cross links
Uses: Broad spectrum
Side effects: Nausea/vomiting, myelosupression, neurotoxicity, ototoxicity, nephrotoxicity, vascular events

Question 19

Describe features of taxanes

Answer 19

Eg, Paclitaxel. Bind to tubulin and inhibit spindle apparatus.
Used: Breast, ovarain, lung and prostate.
Side effects: Myelosupression, allergic reactions, arthralgia, myalgia

Question 20

Why does chemo sometimes fail?

Answer 20

Primary resistance
Secondary resistance - tumour becomes resistant to treatment it was initially responsive to.

Question 21

What are some mechanisms of resistence to chemo?

Answer 21

Efflux pumps,
Gene amplification,
Alterations to cell membrane,
Loss of drug activation,
Change in enzymes

Question 22

How can you prevent resistance to chemo?

Answer 22

Treating the tumour when it’s small,
Use combinations of treatments,
Use effective doses of chemo

Question 23

How do you treat an allergic reaction to chemo?

Answer 23

Stop chem!
Do A-E exam,
Give hydrocortisone, chlorphenamine and adrenaline and IV fluids

Question 24

How can you tell chemo/treatment is working?

Answer 24

Clinical signs or symptoms (nodal mass, QoL)
Tumour markers,
Improvement in organ function,
Radiological response