medwireNews: Patients with small-cell lung cancer (SCLC) and brain metastases may benefit from first-line treatment with stereotactic radiosurgery (SRS), suggest findings from the FIRE-SCLC study.
Lead investigator Chad Rusthoven (University of Colorado School of Medicine, Aurora, USA) and colleagues explain that while SRS “is preferred for limited brain metastases from most histologies, whole-brain radiotherapy (WBRT) has remained the standard of care for patients with small cell lung cancer,” with limited data available on SRS outcomes.
In this cohort study, the researchers analyzed data pertaining to 710 SCLC patients with brain metastases who received SRS, but no WBRT or prophylactic canal irradiation, at one of the 28 participating centers or as part of a single-arm trial of SRS.
As reported in JAMA Oncology, the median overall survival (OS) with SRS was 8.5 months and among the 456 patients with data on central nervous system (CNS) control, the median time to CNS progression was 8.1 months and the median CNS progression-free survival (PFS) was 5.0 months.
CNS progression was more likely to occur in the form of new lesions rather than local failures, with estimated rates of distant CNS failure of 28.0% and 41.6% at 6 and 12 months, respectively, versus corresponding rates of 4.1% and 7.0% for local failures, a pattern similar to that seen with SRS in other settings according to the researchers.
They postulate that a consequence of omitting WBRT may be high rates of leptomeningeal progression and neurologic mortality, but both were deemed “uncommon,” with respective incidence rates of 10.8% and 12.4%.
Furthermore, no treatment-related deaths were reported and the rate of any-grade radiation necrosis was 5%.
These survival benefits associated with SRS were “particularly impressive” among those with a single brain metastasis, say Rusthoven and team, who report a significantly higher median OS of 11.0 months in these patients versus 8.7, 8.0, and 5.5 months for those with 2–4, 5–10, and 11 or more lesions, respectively. The findings were similar for time to CNS progression.
The researchers also performed a propensity score-matched analysis comparing 187 patients from the aforementioned SRS cohort with 187 participants of a previously published cohort who instead received first-line WBRT.
They found that SRS was associated with a significantly better median OS than WBRT (6.5 vs 5.2 months), despite a significantly shorter median time to CNS progression (9.0 months vs not reached) and a comparable median CNS PFS (4.0 vs 3.8 months).
“Although these retrospective data should not be used to conclude that overall survival is superior with SRS, the findings of this study suggest that the primary trade-offs associated with SRS without WBRT, including a shorter [time to CNS progression], are similar to other settings in which SRS alone is well established by multiple randomized clinical trials,” say Rusthoven et al.
And they conclude: “This study provides a benchmark for stereotactic radiosurgery outcomes and suggests that this treatment alone is a potential option for select patients with small cell lung cancer.”
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JAMA Oncol 2020; doi:10.1001/jamaoncol.2020.1271