Cancer: Chemotherapy and Radiotherapy

Question 1

What is chemotherapy?

Answer 1

Cytotoxic drugs used to destroy rapidly proliferating cells by interfering with cell division and is used in the treatment of cancer because it can travel via the bloodstream to treat cancer anywhere in the body. It generally has a low target-specificity.

Question 2

How does chemotherapy work?

Answer 2

Binds to DNA, inhibits enzymes or disrupts the mitotic spindle and mimicks DNA building blocks.

Question 3

In which circumstances can chemotherapy be targeted?

Answer 3

A key feature of cancer cells is the inability to repair DNA damage.

Question 4

What are the drawbacks of chemotherapy?

Answer 4

Does not discriminate and targets cells with a high proliferative ability, especially the cells of the intestinal lining with a high replacement rate.

Question 5

Which cells are affected in chemotherapy?

Answer 5

Bone marrow: leads to anaemia, thrombocytopenia
Intestinal cells: leads to vomiting and GI upset
Hair root cells: causing alopecia
Skin cells: leads to photosensitivity or rashes or pigmentation

Question 6

What are the types of chemotherapy side effects?

Answer 6

Acute and long-term

Question 7

What is a vesicant?

Answer 7

Chemical drug that can cause severe chemical burns and tissue damage. Chemotherapy is a vesicant which causes toxicitiy of the heart, lungs, CNS and endocrine system

Question 8

What are the common side effects of chemotherapy?

Answer 8

Acute toxicity which is self limiting due to normal cells ability to repair
Long term toxicity which is incurable and leads to end organ damage

Question 9

What are the types of acute toxicity in chemotherapy?

Answer 9

Myelosuppression, alopecia and GI toxicities with vomiting and headaches. Cognitive impairments such as confusion and memory loss

Question 10

What are the long term toxicities of chemotherapy?

Answer 10

Infertility, early menopause, fatigue, hearing loss, heart failure

Question 11

What is radical treatment?

Answer 11

Curative treatment

Question 12

What is SACT?

Answer 12

Drug treatment to control or treat cancer which includes surgery, radiotherapy and chemotherapy and targeted treatment.

Question 13

What effects does chemotherapy have on the organs?

Answer 13

Injection of the cytotoxic drug can contain high calcium levels such as anthracyclines which result in heart failure long term
May be lung damage,
Liver steatosis because chemo drugs are lipophilic and taken up
Kidney damage due to the breakdown of the cytotoxic drugs

Question 14

What are the common side effects of chemotherapy?

Answer 14

Extravasation of the drug, alopecia, stomatitis, stimulation of vomiting centre in CNS. C

Question 15

What is the primary cancer treatments?

Answer 15

Surgery to remove tumour only in a specific location
Radiotherapy to kill cancer cells only in the area that it is aimed at
Chemotherapy has systemic cytotoxic effects on cancer cells and travels throughout the body via the bloodstream

Question 16

What is multimodality treatment?

Answer 16

Using more than one type of treatment to treat cancer.

Question 17

What are the types of chemotherapy?

Answer 17

Curative
Adjuvant
Neoadjuvant
Palliative

Question 18

What is curative chemotherapy?

Answer 18

Chemotherapy administered to obtain full cancer remission in the patient, typically used in the treatment of acute lymphocytic leukemia. Typically has an induction phase to destroy any cancer cells and later a consolidation phase to remove any remaining cancer cells.

Question 19

What is adjuvant chemotherapy?

Answer 19

Given after a primary treatment such as surgery or radiotherapy to increase the length of cancer remission. This is beneficial because following removal of a tumour, information about the cancer spread and characteristics can make adjuvant treatment highly tailored to the patient. This is typically done for breast cancer.

Question 20

What is neoadjuvant chemotherapy?

Answer 20

Treatment given to reduce the size of the tumour prior to the primary treatment to increase the likelihood of surgery success and assess the effect of cancer therapy on the disease for bladder cancer and breast cancer.

Question 21

What is palliative chemotherapy?

Answer 21

Intent is to improve quality of patient life, such as pain relief, stress from the illness regardless of diagnosis which is common in solid tumours. Used for pancreatic cancer, breast cancer and non-small cell lung cancer

Question 22

What is radiotherapy?

Answer 22

The use of localised ionising radiation to cause DNA damage to cells as a treatment of cancer via direct or indirect methods.

Question 23

What are the types of radiotherapy?

Answer 23

External radiotherapy and internal radiotherapy

Question 24

What is external radiotherapy?

Answer 24

Machine called external beam directs ionising radiation to the body.

Question 25

What are the types of external beam?

Answer 25

Conventional external beam
Stereotactic radiation
Particle radiation
3D Conformal radiotherapy

Question 26

How does radiation damage occur?

Answer 26

Via rexoygenation where radiation causes loss of electrons from cell which reacts with oxygen to form a superoxide radical that causes DNA damage.

Question 27

What is conventional external beam?

Answer 27

2D beams deliver high energy X rays using medical linear accelerator to tumour but high dose is limited by effect on healthy tissue.

Question 28

What is Stereotatic radiation?

Answer 28

Focused angles of different beams of radiation localised to the tumour in a short amount of time with a lower dose so less effect on surrounding tissue. Only ideal for smaller tumours.

Question 29

What is particle radiation?

Answer 29

Consists of a beam of protons, neutrons and electrons directed to tumour which reduces energy deposited to surrounding tissue

Question 30

What is 3D Conformal radiotherapy?

Answer 30

Multiple radiation beams are directed to conform to tumour shape using a multileaf collimator/

Question 31

What is indirect radiotherapy?

Answer 31

Ionising radiotherapy is targeted to the water surrounding cancer cells and causes free radicals to form which react with oxygen to form superoxide radicals that cause DNA damage.

Question 32

What is direct radiotherapy?

Answer 32

Ionising radiotherapy is targeted directly to cancer cells and causes double stranded DNA break, ideally during the end of the M phase of cancer cells when it is most susceptible to DNA damage. This is done in segments via fractionation.

Question 33

What is fractionation?

Answer 33

Providing radiotherapy over the course of many days because cancer cells are in different stages of division. This ensures normal cells that are damaged have enough time to repair and that most cancer cells are damaged enough to prevent repopulation by non-damaged cells.

Question 34

What is brachytherapy?

Answer 34

Internal radiotherapy which inserts radiation source inside or close to tumour site to deliver higher dose treatments. This requires high tumour accessibility and clear demarcation.

Question 35

What is pre-operative XRT?

Answer 35

Radiotherapy given before surgery which decreases extensiveness of surgery and distant metasasis due to surgery, makes microscopic cancers more radiosensitive. Also creates a smaller treatment portal (extent in bloodstream). It can make previously unsecetable tumours become resectable.

Question 36

What are the drawbacks of pre-operative XRT?

Answer 36

Reduces wound healing rate and lower safe dose.

Question 37

What is post-operative XRT?

Answer 37

Providing radiotherapy after surgery which means a greater dose can be given dependent on the residual tumour burden, allows surgical staging (tumour can be assessed post-surgery) and improves healing and make surgical resection easier.

Question 38

What are the drawbacks of post-operative XRT?

Answer 38

Delay in providing post-operative treaments if there are healing problems and potential distant metastasis due to manipulation

Question 39

What are the acute side effects of radiotherapy?

Answer 39

Occurs during treatment depending on area treated:
Damage to epithelial surfaces causing skin to become pink and sore
Mouth, throat and stomach sores
INfertility due to sensitivity of gonads to radiation
Intestinal discomfort

Question 40

What are the late side effects of radiotherapy?

Answer 40

Occurs weeks-> months after treatment
Tissue fibrosis
Dry eyes and mouth
Hair loss
Lymphaedema

Question 41

How can cancer cells become resistant to chemo drugs?

Answer 41

Contain the MDR-1 gene, which codes for P-glycoprotein for increased efflux of drugs to protect the brain. Increases resistance to alkaloids, anthracyclines and epipodophyllotoxins.

Question 42

What is the role of topoisomerase?

Answer 42

Relaxing of DNA supercoils to break and reattach for DNA replication for the topology of DNA

Question 43

What is anthracycline?

Answer 43

Anti-tumour drug which inhibits topoisomerase
Inihibits DNA helicase activity by intercalating between the DNA bases
Induces ROS production to induce apoptosis

Question 44

What is the action of anti-metabolites?

Answer 44

Inhibits DNA and RNA synthesis by targeting thymidylate synthase which catalyses dUMP -> dTMP and Methylene THF -> DHF.

Question 45

Which nucleotide is most affected by action of anti-metabolite?

Answer 45

Thymine nucleotide which is produced from the methylene THF donated a methyl group to uracil -> thymine

Question 46

What are the methods of cancer resistance to drugs?

Answer 46

Primary drug resistance
Secondary drug resistance

Question 47

What is stage?

Answer 47

Extent of cancer spread. This is commonly in the

Question 48

What are the invasive diagnostic procedures for cancer?

Answer 48

Colonoscopy, bronchoscopy and laparoscopy.

Question 49

What are the biochemical investigations?

Answer 49

Protein and electrolytes
Liver enzymes
Tumour markers such as PSA (prostate specific antigen) and HCG