Is it acceptable to treat patients with limited, asymptomatic brain metastases and EGFR-mutant NSCLC with upfront TKI?

Though some clinicians have been exploring the idea of targeted therapy for EGFR mutant brain metastases, this has been done in the absence of strong evidence. Reasons for pushing this idea are that sometimes the lesions seem to respond, and this has been seen in some single arm studies and anecdotally. However, the response rate of EGFR mutant brain metastases to targeted therapy still pales in comparison to the "response" rates to radiosurgery - arguably in the 95%-99% range. Almost all EGFR mutant brain metastases from lung cancer primaries "respond" to radiotherapy.

We were interested in this comparison and so performed a single institution (Magnuson et al., PMID 27034176) as well as our just-published multi-institutional study (Magnuson...

I would treat patients with limited, asymptomatic brain metastases with SRS followed by EGFR-TKI based upon the studies (particularly the recently published Journal of Clinical Oncology study) cited by @Dr. First Last above.

In full disclosure, I am obviously the first author on both of the manuscripts cited by @Dr. First Last. Nonetheless, the data speaks for itself. I could understand if one were to write off the robust results favoring upfront SRS in our Yale single-institution study because of small sample size (n=50) and perhaps some unknown institutional bias of how we treated our patients. I wanted to know if our results were merely a phenomenon seen in our cohort or if it was representative of what was really occurring in this patien...

In the era of newer generation TKIs with increased CNS activity (e.g., osimertinib for EGFR+; alectinib, lortlatinib, brigatinib for ALK+ NSCLC), the short answer is “yes”, it is acceptable to treat carefully selected patients with limited brain metastases with upfront CNS-active TKIs and close MRI surveillance. It is also acceptable to offer early stereotactic radiosurgery (SRS), either upfront or as consolidation. An important question is, what are the clinical tradeoffs associated with these management options?

Retrospective data from the era of first-generation TKIs with less CNS activity, including erlotinib and crizotinib, reported that clinical outcomes including CNS control and possibly even OS (with all the caveats of retrospective ...

I think the answers to this question above make some great points. However, old data on this topic are now a bit outdated with the recent results of the FLAURA trial which moved the third-generation TKI osimertinib to first-line therapy for EGFR-mutants.

Most of the first and second-line EGFR agents (erlotinib and others) do not cross the blood-brain barrier very well. Osimertinib, however, has good penetration as shown in monkeys in pre-clinical data. FLAURA provides the first strong randomized data in humans that there is activity. In the subset of patients with "known or treated" brain mets (a vague term to me), the rate of any CNS progression after osimertinib was only 19%, as compared to the control arm of 43%, suggesting meaningful act...

I often hold off on RT if lesions small and asymptomatic. But I never stop close surveillance.

New data from a randomized study in EGFR & ALK mutated NSCLC patients with asymptomatic brain mets demonstrate that upfront CNS treatment with either SRS or WB-XRT +/- boost delayed intracranial progression compared to delayed treatment. There was no difference in overall progression or overall survival between the two groups. Median follow-up was just over 2 years, so perhaps a survival benefit will be demonstrated with further follow-up. No information on what triggered CNS treatment in the delayed arm was provided. No information on neurological symptoms in either arm was provided. They did report rates of radiation necrosis in the upfront CNS treatment arm (25% <= grade 2, 6% >= grade 3). This new information supports upfront radiothera...

I would likely proceed with SRS upfront for limited small metastasis and asymptomatic and consider holding off if patient is comfortable with close surveillance.

I would treat with SRS now to prevent problems in future. Besides, I think patients with known brain mets will really worry if not treated.

In my opinion, patients with asymptomatic brain mets from EGFR-mutated NSCLC can initially be treated with erlotinib. I have had a few such cases, and initially the brain mets respond to erlotinib. However, they appear to universally progress in the brain necessitating radiotherapy or SRS. Studies indicate that these patients do worse than EGFR-mutated patients without brain metastasis, which is not surprising. A retrospective Chinese study demonstrated timing of radiotherapy had no difference in overall survival.

Liu et al., PMID 26014133

I would treat if the patient wishes to be on close surveillance with repeat MRI. Most of my patients prefer treatment than getting frequent MRI studies.