12 Radiation Therapy

Question 1

Which tumors are responsive to radiation therapy? (6)

Answer 1

Wilms, Ewings, neuroblastoma, leukemia/lymphoma, PNET and high grade glioma

Question 2

Are tumors with rapid cell growth more or less radiosensitive.

Answer 2

More, they respond better to XRT slide 8

Question 3

What is brachytherapy and when to use it?

Answer 3

Brachytherapy is the temporary or permanent implantation of radioactive seeds or pellets directly into a body cavity, tissue, or skin surface. It provides a prescribed dose of radiation to a localized area. This mode of delivery in pediatric cancers has been used for soft-tissue tumors, brain tumors, and retinoblastoma.

Question 4

In radiation, why would you do fractionation (1 dose a day) or hyperfractionation (2 doses a day, at least 6h apart)?

Answer 4

To allow higher doses with less toxicity.

Question 5

XRT works best in which 2 parts of cell cycle?

Answer 5

M, G2

Question 6

What is radiation recall?

Answer 6

A radiation recall reaction is side effects that recur after the administration of some types of chemotherapy.

Question 7

How long can radation related fatigue last?

Answer 7

weeks or even months after XRT is complete. usually starts a few weeks in.

Question 8

When is myelination complete? (aka below which age do you try to avoid radiation due to severe neuro effects)

Answer 8

3 years old.

Question 9

What is hypersomnolence syndrome? When can it occur? How can you treat it?

Answer 9

weeks-months after XRT - headache, fatigue, somnolence, N/V, slow mentation. usually self limiting and resolves in a few weeks. If sevee, you can do a short course of steroids.

Question 10

What is Lhermitte’s sign?

Answer 10

Myelopathy within months of spinal radiation - sensation of electrick shock down the spine when nexk is flexed. usually resolves

Question 11

Why is short stature from spinal radiation a concern? How to keep growth even??

Answer 11

premature closing of growth plates prevents further growth. Irradiate both sides of vertebrae equally or it may result in uneven growth.

Question 12

What chemo does should be lower when used with XRT to decrease likelihood of damage?

Answer 12

anthracyclines

Question 13

XRT can cause fever/dyspnea and pericardial friction rub due to inflammaton and thickening of what

Answer 13

pericardium. Called acute pericarditis. Within 2-30 mo after radiation. Usually self limiting, can treat with steroids.

Question 14

Which med should not be given with XRT due to risk of hemorrhagic cysitis?

Answer 14

cyclophosphamide

Question 15

Why should hgb be 10 or higher for XRT?

Answer 15

to optimize oxygenation. XRT works best on oxygenated cells

Question 16

When do skin reactions to radiation typically occur?

Answer 16

10 days after beginning radiaton

Question 17

What is the purpose of TBI?

Answer 17

The purpose of TBI in HPCT is to cause bone marrow aplasia. By emptying out the bone marrow space, new progenitor cells have room to grow. After TBI, the patient would die of overwhelming infection if stem cells were not given.

Nuclear plant accidents, such as Chernobyl in Russia, in effect delivered TBI to people living close to the accident, and more than 100 people received stem cell therapy in an attempt to repopulate their bone marrow.

Question 18

What is used for skin care during radiation?

Answer 18

water based lotions, no antibac cleaners, clean dry skin, no anti-inflammatory (can thin skin and reduce healing)

Question 19

Most likely initial side effect of posterior fossa radiation?

Answer 19

nausea and vomiting. pretreat.