Treatment fundamentals

Question 1

Treatment intent

Answer 1

radical, palliative or to enhance local control in the non curative patient

Question 2

Why do we fractionise doses

Answer 2

o 10 Gy to the whole body can cause major biological harm
o Can deliver high dose if not delivering to the whole body, but instead the specific tumour (avoiding bone marrow, OAR)
o Cells may be able to turn over faster during radiation treatment
o 2 Gy is the standard fractionation size

Question 3

What is therapeutic ratio

Answer 3

o Sublethal damage repair
Comparison between NTCP and TCP

o relationship between the probability of tumor control and the likelihood of normal tissue damage

Question 4

NTCP

Answer 4

Normal tissue complication probability

Question 5

TCP

Answer 5

Tumour control probability

Question 6

Radical treatments and chances of success

Answer 6

• Cervical high probability of curative (>90%)
• Breast (>90% chance of cure)
• Seminoma (very radiosensitive, can use low doses)
• Prostate (very radioresistant. >90% chance of cure)
• Lung (treat with radical dose, however survivability is quite low – 5 to 10% after 5 to 10 years)
• Sarcoma (treated with radical, low survivability)

Question 7

Radiocurable Tumours

Answer 7

• Non-melanoma skin cancer
• Epithelial cancers of the head and neck
• Carcinoma of the uterine cervix
• Carcinoma of the prostate
• Hodgkin’s and non-Hodgkin’s lymphoma
• Seminoma of the testicle and dysgerminoma of the ovary
• Medulloblastoma, pineal germinoma ependymoma
• Retinoblastoma

Question 8

What is palliative treatment

Answer 8

• An approach that improves the quality of life of patients and their families facing the problems associated with life-threatening illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems, physical, psychosocial, and spiritual

Question 9

Local control

Answer 9

• May be a bleeding lung tumour that causes haemoptysis (coughing blood) for the patient
o Cells can become necrotic, which can trigger other reactions that eventually lead to bleeding
o Uncontrolled bleeding is severe, as the blood will not clot

• May be related to SVC compression
o Head may swell, venous pathways may swell as pressure within vessels build
o Patient cannot lie down – have to sit in a chair

Question 10

Treatment of a Patient requirements

Answer 10

• The optimal use of radiation therapy requires meticulous planning, preparation and implementation
• Designing treatment starts with the recognition of the known and potential extent of the disease

Question 11

Normal tissue complication

Answer 11

o Damage to the normal tissue

o Aim is to have minimal complication with the desirable tumour cell control