Radiotherapy and the roles of radiotherapy

Question 1

What percentage of all cured cancer patients are cured via radiotherapy?

Answer 1

40%

Radiotherapy is a significant treatment modality in cancer care.

Question 2

What is the second most important cancer-curing treatment after surgery?

Answer 2

Radiotherapy

This highlights the crucial role of radiotherapy in cancer treatment.

Question 3

Name three curative intent uses of radiotherapy.

Answer 3

• Inoperable disease
• Organ preservation
• Primary or adjunctive treatment

These uses demonstrate the versatility of radiotherapy in managing cancer.

Question 4

What are the palliative uses of radiotherapy?

Answer 4

• Symptom control
• Pain
• Bleeding
• Obstruction

Palliative care aims to improve the quality of life for patients.

Question 5

What is External Radiotherapy (EBRT)?

Answer 5

Delivered in fractions over days/weeks using a Linear Accelerator (Linac)

EBRT is a common method for administering radiotherapy.

Question 6

What machines are used for External Radiotherapy?

Answer 6

• Linear Accelerator (Linac)
• Cyberknife
• Gammaknife

These machines vary in technique and application.

Question 7

True or False: An individual is radioactive after undergoing External Radiotherapy.

Answer 7

False

Patients do not retain radioactivity post-procedure.

Question 8

What is Brachytherapy?

Answer 8

A solid radioactive source placed inside a body cavity

Commonly used for prostate, cervical, and rectal cancers.

Question 9

What is a key characteristic of Radionuclide therapy?

Answer 9

Oral/IV administration and the patient is radioactive afterwards

Examples include Strontium for prostate bone metastases and Iodine for thyroid cancer.

Question 10

Fill in the blank: Radiotherapy is used in cases of _______ disease.

Answer 10

Inoperable

This use underscores the importance of radiotherapy when surgery is not an option.

Question 11

What is the primary purpose of radiotherapy?

Answer 11

Uses tumoricidal doses to kill tumour cells.

Question 12

What is the unit of radiation dose?

Answer 12

Gray (Gy) is the unit of radiation dose.

Question 13

What does radiotherapy target while sparing normal tissue?

Answer 13

Targets tumour while sparing normal tissue (OAR: organs at risk).

Question 14

What is fractionation in radiotherapy?

Answer 14

Small dose delivered daily allows recovery of normal tissues (conventional) or large dose delivered to small target (stereostatic ablative body radiotherapy/SABR).

Question 15

How does radiotherapy damage cancer cells?

Answer 15

Damages DNA during replication leading to cancer cell death.

Question 16

What are radiosensitisation drugs used for?

Answer 16

Drugs used to enhance effect of RT.

Question 17

Give an example of a radiosensitisation drug.

Answer 17

Example: BCON (Bladder Carbogen and Nicotinamide) for bladder cancer.

Question 18

What is hypoxia in relation to tumors?

Answer 18

Hypoxia can cause resistance to radiotherapy.

Question 19

What causes tumor hypoxia?

Answer 19

As tumors grow, they outstrip their blood supply leading to hypoxia.

Question 20

What is BCON?

Answer 20

Bladder carbogen and nicotinamide (BCON) is an alternative to chemo-radiation in the treatment of bladder cancer if chemotherapy is contraindicated.

Question 21

What is carbogen?

Answer 21

Carbogen is a mixture of 98% oxygen and 2% carbon dioxide.

Question 22

How is nicotinamide administered?

Answer 22

Nicotinamide is administered orally.

Question 23

What are the pre-treatment steps in radiotherapy planning?

Answer 23

Histology, staging, assessment, immobilisation, tattoos to mark the area, contouring to mark tumor & OAR, and online imaging to improve accuracy.

Question 24

What are key tools/techniques in radiotherapy planning?

Answer 24

Virtual simulation, CT planning scan, and image guidance for precision.

Question 25

What is the typical process for a CT planning scan?

Answer 25

The majority of patients have a CT planning scan, and patient factors include being able to lie flat, remain still, and safely lie unattended on a high/thin couch.

Question 26

How often are treatments scheduled?

Answer 26

Treatments are scheduled on consecutive days (Monday to Friday) with appointments lasting 10-20 minutes.

Question 27

What do modern planning techniques achieve?

Answer 27

Modern planning techniques reduce dose to normal tissues.

Question 28

How does image guidance impact treatment?

Answer 28

Image guidance improves accuracy and allows for smaller treatment margins.

Question 29

What are common general side effects of radiotherapy?

Answer 29

Fatigue and appetite loss.

Question 30

How are side effects characterized?

Answer 30

Side effects are localized within the irradiated field, dose-dependent, and predictable.

Question 31

What is acute toxicity?

Answer 31

Acute toxicity occurs within 10–14 days and affects rapidly dividing cells (skin, gut, marrow, and mucous membranes), healing within 2–4 weeks.

Question 32

What is late toxicity?

Answer 32

Late toxicity occurs ≥6 months post-radiotherapy, is less common (<5% incidence), dose limiting, predictable but not inevitable, and may include fibrosis and vessel damage.

Question 33

What is the incidence of rare carcinogenesis post-radiotherapy?

Answer 33

The incidence of rare carcinogenesis is approximately 0.1%.

Question 34

What are examples of late toxicity years after radiotherapy?

Answer 34

Examples include sarcoma and breast cancer years after radiotherapy for Hodgkin's lymphoma when chemotherapy was not an option.