Can a second course of SRS be used to treat a brain met that initially responded to SRS and then progressed?
If progression is proven by imaging modality (MRI spectroscopy, perfusion and PET/CT), is there evidence for retreatment with a second course of SRS? If so, should a lower dose be used than would be typically used for the same size lesion?
Answer from: Radiation Oncologist at Community Practice
One should use caution in interpreting imaging as a definitive sign of progression, as sometimes radiation necrosis can mimic those findings. if asymptomatic, the patient can be considered for close observation with imaging and if symptomatic, one should consider a surgical option also.
Answer from: Radiation Oncologist at Academic Institution
If there is compelling evidence for recurrence, there are a few small case series that demonstrate feasibility of repeat SRS. We recently presented our own series at ASTRO (http://www.redjournal.org/article/S0360-3016(14)01740-4/fulltext) demonstrating a 1y LRFS of 62.4% with 17% risk (4 pts) of gra...
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Radiation Oncologist at Radiant Oncology If it were biopsy proven vs surgically resected, w...
Answer from: Radiation Oncologist at Community Practice
I agree with caution in interpreting the results of PET and MRI spectroscopy. The specificity of PET, MRI, and MR spectroscopy vary from 50-80%. We have had a number of cases in which PET and MR spec were consistent with progressive disease and surgical pathology on the whole lesion showed radionecr...