When imaging is ambiguous between radiation necrosis and tumor progression in the brain, a short course of high-dose dexamethasone can serve as a diagnostic tool. Imaging improvement after steroids strongly suggests radionecrosis, potentially avoiding an invasive biopsy.
A blinded central radiology review is not the absolute gold standard for assessing patient progression. Expert clinicians argue their holistic assessment, incorporating the patient's clinical status and other biomarkers alongside scans, provides critical context that a disconnected reviewer lacks.
In cases of suspected glioma recurrence post-radiation, FET PET imaging can provide a more accurate diagnosis than MRI perfusion, even when MRI findings suggest tumor growth. This allows clinicians to avoid unnecessary changes in therapy based on potentially misleading MRI data.
With new CNS-active drugs dramatically improving survival after a brain metastasis diagnosis, some experts are now advocating for routine screening brain MRIs in high-risk patients. The goal is to detect asymptomatic lesions early, potentially preventing catastrophic neurologic events like seizures.
Retrospective data reveals a four-fold increase in radiation necrosis when antibody-drug conjugates (ADCs) like TDXD or TDM-1 are given within weeks of stereotactic radiosurgery (SRS). Clinicians should pause ADC treatment for at least one cycle around SRS to mitigate this serious complication.
For patients with otherwise well-controlled disease who develop isolated oligoprogression in the brain, evidence suggests a better survival outcome from adding local therapy (like SRS) and continuing the current effective systemic therapy, rather than switching the systemic regimen entirely.
After immunotherapy, many colorectal cancer patients have residual nodules on scans that appear to be partial responses. However, ctDNA testing can confirm these are often just scar tissue, not active disease. This provides the confidence to stop therapy at the two-year mark and avoid unnecessary surgeries for what are effectively complete responses.
A practical method to monitor radioligand therapy is a post-treatment SPECT scan. Since the therapeutic agent is radioactive, a simple planar scan about 24 hours after injection can visually confirm where the drug was delivered. This provides real-time feedback, beyond PSA levels, to potentially adapt treatment.
In low-grade gliomas, FET PET can pinpoint metabolically active regions within larger, non-specific areas of flare signal abnormality. This helps neurosurgeons target biopsies or resections to the most aggressive parts of the tumor, potentially identifying transformation to a higher grade.
The intensity and volume of FET PET activity serve as a powerful prognostic marker in glioma patients. Even when imaging suggests treatment-related changes rather than active tumor, elevated PET signals still correlate with a worse overall outcome, providing an additional layer of risk stratification.
Regularly scheduled FET PET scans over extended periods help clinicians confidently monitor fluctuating lesions. This longitudinal data provides the reassurance needed to be patient and avoid prematurely escalating treatment for what may ultimately prove to be benign, treatment-related changes.