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PURPOSE To provide a final update on oncologic and cognitive outcomes of high dose versus low dose radiation for low-grade glioma. METHODS Between 1986 and 1994, 203 patients with supratentorial low grade glioma were randomized to 50.4 Gy in 28 fractions versus 64.8 Gy in 36 fractions after any degree of resection. Histologic subtype was oligodendroglioma (71%) or astrocytoma (29%). Primary outcome was overall survival (OS). Cognitive status was followed using Folstein Mini-Mental State Examination (MMSE). RESULTS For the entire cohort of 203 patients, median OS was 8.4 years (95% CI: 7.2 – 10.8). Median progression-free survival (PFS) was 5.2 years (95% CI: 4.3 – 6.6). Median follow-up is 17.2 years for the 33 patients still alive. High-dose radiation did not improve OS (15-yr OS: 22.4% vs. 24.9%, log rank p=0.978) or PFS (15-yr PFS: 15.2% vs. 9.5%, p=0.7142). OS was significantly better for patients with pre-operative tumor diameter < 5 cm (15-yr OS: 39.4% vs. 15.2%, p< 0.001), baseline MMSE > 27 (15-yr OS: 27.3% vs. 9.8%, p=0.001), and for patients who underwent gross total resection (GTR) (15-yr OS: 39.3% GTR vs. 16.4% subtotal resection vs. 24.5% biopsy only, p=0.0119). PFS was improved for patients with oligodendroglioma versus astrocytoma (15-yr PFS: 13.8% vs. 8.6%, p=0.0221). PFS was also improved for patients with pre-operative tumor diameter < 5 cm, patients who had GTR, and patients with baseline MMSE > 27. For patients who had normal MMSE at baseline, at 7 years only 1 patient (5%) had a clinically significant decrease in MMSE from the previous time point, with the remainder (95%) stable. None had decrease in MMSE at 10, 12, or 15 years. CONCLUSIONS Long-term follow-up indicates no benefit to high-dose over low-dose radiation for low-grade gliomas. Minimal late decline in cognitive function after radiation was seen by MMSE. SUPPORT: U10CA180821,U10CA180882. https://acknowledgments.alliancefound.org

BACKGROUND: WBRT significantly improves tumor control in the brain after SRS, yet the role of adjuvant WBRT remains undefined due to concerns regarding neurocognitive risks. METHODS: Patients with 1-3 brain metastases, each 1 SD from baseline in any of the 6 cognitive tests at 3 months. Time to CP was estimated using cumulative incidence adjusting for survival as a competing risk. RESULTS: 213 patients were enrolled with 2 ineligible and 3 cancels prior to receiving treatment. Baseline characteristics were well-balanced between study arms. The median age was 60 and lung primary the most common (68%). CP at 3 months was more frequent after WBRT + SRS vs. SRS alone (91.7% vs. 63.5% respectively, p = 0.0007). There was more deterioration in the WBRT + SRS arm in immediate recall (30% vs. 8%, p = 0.0043), delayed recall (51% vs. 20%, p = 0.0009), and verbal fluency (19% vs. 2%, p = 0.0098). After WBRT + SRS there was more deterioration in overall QOL (p = 0.001) and functional well-being (p = 0.006) at 3months. Intracranial tumor control at 3 and 6 months were 75.3% and 64.7% with SRS alone vs. 93.7% and 88.4% with SRS + WBRT (p < 0.0001). Median OS was 10.4 for SRS alone vs. 7.4 months for SRS + WBRT respectively (HR = 1.02, p = 0.92). CONCLUSIONS: Decline in QOL and cognitive function, specifically immediate recall, memory and verbal fluency, was more frequent with the addition of WBRT to SRS. Adjuvant WBRT did not improve OS despite better brain control. Initial treatment with SRS and close monitoring is recommended to better preserve cognitive function in patients with newly diagnosed brain metastases that are amenable to SRS.