Follow-up/Toxicity

Question 1

What are potential acute toxicities of WBRT?

Answer 1

Potential WBRT acute toxicities: alopecia, fatigue, HA, n/v, ototoxicity

Question 2

What are potential long-term toxicities of WBRT?

Answer 2

Potential WBRT chronic toxicities: thinned hair, decline in short-term memory, altered executive function, leukoencephalopathy, brain atrophy, normal pressure hydrocephalus, RT necrosis

Question 3

What is the relationship between WBRT-induced brain mets shrinkage and neurocognitive function?

Answer 3

WBRT-induced brain met shrinkage correlates with improved neurocognitive function. This was demonstrated in an analysis of 208 pts with brain mets randomized to WBRT alone on a phase III trial of WBRT +/– motexafin gadolinium. Pts with a good response to WBRT (>45% tumor volume reduction at 2 mos) had a longer time to decline in neurocognitive function. (Li J et al., JCO 2007)

Question 4

What is the reported risk of severe dementia with WBRT?

Answer 4

DeAngelis L et al. reported an 11% (5 pts) risk of radiation-induced dementia in long-term brain mets survivors (>12 mos) based on a retrospective review of 47 pts Tx with WBRT. 3 pts were treated with nonstandard fractionation, 1 pt rcvd concurrent Adr, and 1 pt rcvd 30 Gy in 3 Gy/fx with a radiosensitizer. Of 15 pts Tx with <3 Gy/fx without systemic therapy, 0 developed severe dementia or neurocognitive Sx. (Neurosurgery 1989)

Question 5

What is the most important determinant of neurocognitive function?

Answer 5

The most important determinant is brain tumor control/delay of intracranial progression.

Question 6

What other factors contribute to neurocognitive decline?

Answer 6

Anticonvulsants, benzodiazepines, opioids, chemo, surgical intervention (craniotomy), and systemic progression of Dz

Question 7

What daily fx size in WBRT is associated with RT necrosis?

Answer 7

WBRT administered in fx sizes >3 Gy/day are associated with RT necrosis. (DeAngelis L et al., Neurology 1989)

Question 8

Name the potential acute toxicities of SRS for brain mets.

Answer 8

Potential acute toxicities of SRS for brain mets: HA, nausea, dizziness/vertigo, seizure

Question 9

What is the risk of symptomatic RT necrosis after SRS for brain mets?

Answer 9

There is an ∼5% risk of symptomatic RT necrosis secondary to SRS for brain mets. This is usually treated with steroids but may require Sg or bevacizumab for refractory cases.

Question 10

What are the dose limits to critical structures with SRS?

Answer 10

Brainstem 12.5 Gy, optic chiasm or optic nerves 10 Gy, other cranial nerves 12 Gy