What "normal brain - PTV" dose constraint would you recommend for a large solitary cerebellar metastasis, planning 3 or 5 fraction SRT?
For an elderly man presenting with large solitary cerebellar metastasis from melanoma, is your constraint different for cerebellar vs cerebral metastasis?
1 Answer
Mednet Member
Radiation Oncology · Lynn Cancer Institute - Baptist Health City, Baptist Health South Florida
Answered on · Updated on
There are two relevant studies that I utilize for planning considerations: HyTEC (which examined data from 51 reports for NCTP modeling for 1-, 3-, and 5-fractions) as well as Upadhyay et al. (which examined outcomes from a high-volume single-institution center where 3 fractions is their institutional standard for larger brain metastases/cavities):
HyTEC found the following to be associated with <10% risk of any necrosis or edema, and <4% risk of radionecrosis requiring resection:
- Brain plus target volume V20 (3-fractions) <20 cm3
- Brain plus target volume V24 (5-fractions) <20 cm3
I typically ask to report without target volume as well, given that typically these lesions/cavities are quite large if fractionating.
Upadhyay et al. found both V20 a...
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