Dr Rimas Lukas discusses four practice-relevant advances across brain metastases and glioma presented at ASCO 2026
At the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, several neuro-oncology presentations focused less on introducing entirely new paradigms and more on defining where existing and emerging therapies may best fit. Across brain metastases and glioma, phase 3 data addressed longstanding practical questions around radiation delivery, chemotherapy duration, and local therapies, while updated targeted therapy data in IDH-mutant glioma continued to mature. In this piece, Dr Rimas Lukas (Vice Chair of Neurology, Northwestern University, Chicago, IL, USA) highlights four main abstracts from ASCO 2026, discussing their take-aways and considering their potential relevance for clinical practice.
touchONCOLOGY coverage of ASCO 2026
ROADS
→ Abstract LBA2000: Weinberg JS, Lin HY, McAleer MF, et al. Final results of a randomized, controlled, phase 3 trial comparing resection and post-operative stereotactic radiation versus resection and cesium-131 tile-based radiation for treatment of newly diagnosed brain metastases. Presented at: ASCO, Chicago, IL, USA. May 29 to June 2, 2026.
In the phase 3 ROADS study (NCT04365374), investigators compared standard post-operative stereotactic radiation (SRT) with cesium-131 tile-based radiation therapy (TBRT) in patients undergoing resection for newly diagnosed brain metastases. The study randomized 230 patients across 32 USA centers, with 204 included in the modified intention-to-treat population. After a median follow-up of 12.9 months, surgical bed recurrence occurred in 11.9% of patients receiving SRT versus 1.0% with TBRT. Median time to recurrence was 17.4 months with SRT and was not reached with TBRT (HR 0.06; 95% CI 0.01–0.46; p=0.007). Surgical bed recurrence-free survival was also improved (HR 0.48; 95% CI 0.30–0.76; p=0.002). Overall survival favored TBRT (HR 0.59; 95% CI 0.37–0.96; p=0.032), with estimated 24-month survival rates of 35.7% versus 61.7%. Radiation necrosis rates were similar between arms (6.9% vs 7.8%), and grade ≥3 treatment-related adverse events were comparable.
Key clinical takeaways
With superior outcomes in patients treated with implantable Cesium-131 tiles compared to post-operative SRS, there is the potential for substantial changes in standard clinical practice. It will be interesting to see the full study results in the form of a peer reviewed manuscript. Potential factors which drove these differences in outcome include immediate delivery of radiation (as opposed to variable delay with SRS) as well as higher doses of radiation delivered to a small field (an aspect which was not substantially highlighted in the presentation). The radiobiology of this treatment approach may explain differences in outcome when compared to external bean delivery of post-operative radiation.
MAGMA
→ Abstract 2004: Gedye C, Cuff KE, Lau PK, et al. MAGMA: Multi-arm glioblastoma Australasia phase 3 trial. Presented at: ASCO, Chicago, IL, USA. May 29 to June 2, 2026.
The multi-arm phase 3 MAGMA trial (ACTRN12620000048987; COGNO cooperative trials group) addressed two practical questions in newly diagnosed glioblastoma: whether starting temozolomide earlier after surgery improves outcomes, and whether extending adjuvant treatment beyond six cycles is beneficial.
Among 259 patients randomized in the early temozolomide comparison, starting temozolomide at a median of 21 days post-surgery did not improve outcomes. Median overall survival was 16 months versus 20 months for standard timing (HR 1.18; 95% CI 0.89–1.56; p=0.24), and median progression-free survival was 8 versus 9 months (HR 1.15; p=0.31).
For the extended adjuvant question (n=291), median overall survival was 20 months with prolonged treatment versus 18 months with standard six cycles (HR 0.82; 95% CI 0.63–1.06; p=0.13). Notably, multivariable analysis yielded an HR of 0.73 (0.56–0.95), although this was not the prespecified primary analysis.
Key clinical takeaways
MAGMA provides randomized evidence against routine use of ‘early’ pre-radiotherapy temozolomide. This helps settle a question previously informed mainly by smaller phase 2 datasets. For extended adjuvant temozolomide, the data remain more nuanced. While the primary endpoint was not met, the possibility of a modest benefit cannot be excluded. However, the fact that fewer than half of patients remained progression-free long enough to receive extended treatment highlights a practical limitation of this strategy.
JCOG1703 (MACS study)
→ Abstract 2001: Saito R, Kumabe T, Mizusawa J, et al. A multicenter randomized phase III study for newly diagnosed, maximally resected glioblastoma comparing carmustine wafer implantation followed by chemoradiotherapy with temozolomide versus chemoradiotherapy alone: Japan Clinical Oncology Group study JCOG1703 (MACS study). Presented at: ASCO, Chicago, IL, USA. May 29 to June 2, 2026.
In the JCOG1703 (MACS) study, presented by Ryuta Saito, investigators evaluated whether adding carmustine wafers at surgery improves outcomes when combined with standard temozolomide-based chemoradiotherapy. This randomized phase 3 study enrolled 221 patients with newly diagnosed glioblastoma after at least 90% resection. Patients received either carmustine wafer implantation followed by chemoradiotherapy or chemoradiotherapy alone. Median overall survival was 21.7 months in the control arm and 27.7 months in the carmustine wafer arm, but this difference was not statistically significant (HR 0.907; 91.5% CI 0.691–1.192; one-sided p=0.269). There were also no significant differences in progression-free survival (9.5 vs 10.4 months) or loco-regional progression-free survival (10.6 vs 12.7 months). Toxicity and postoperative complication rates were similar.
Key clinical takeaways
This study addresses an important unanswered question and suggests that carmustine wafers do not add meaningful benefit when standard chemoradiotherapy is feasible after maximal resection. These findings may further limit the role of wafer implantation in routine practice, particularly given its surgical complexity and cost. The study also reinforces the prognostic significance of MGMT promoter methylation, which remained strongly associated with improved outcomes.
This study has some analogies to the MAGMA trial, in that the immediate use of alkylating chemotherapy (in this case implantable BCNU wafers and in MAGMA early initiation of oral temozolomide) does not improve survival. In turn, with the results of these and other studies, we have landed back on the original phase 3 EORTC/NCIC ‘Stupp’ regimen (first published in NEJM 2005) as our standard dosing schedule.
INDIGO
→ Abstract 2010: Cloughesy TF, van den Bent MJ, Blumenthal DT, et al. A global, randomized, double-blinded, phase 3 trial of vorasidenib vs placebo in patients with grade 2 glioma with an IDH1/2 mutation (INDIGO): Updated efficacy and safety. Presented at: ASCO, Chicago, IL, USA. May 29 to June 2, 2026
Updated phase 3 data from the INDIGO trial (NCT04164901) provided longer-term follow-up for vorasidenib in patients with grade 2 IDH1/2-mutant glioma. The trial randomized 331 patients to vorasidenib or placebo after surgery alone. With a median follow-up of 41.6 months, median progression-free survival among patients randomized to vorasidenib was 49.9 months (95% CI 39.6–NE). At 42 months, 59.2% of patients remained progression-free, and 75.1% had not required chemoradiotherapy or further surgery. The objective response rate was 31.5%. No new safety signals emerged, and the safety profile remained consistent with prior analyses. Median overall survival was not reached.
Key clinical takeaways
The updated data strengthen the original INDIGO findings and support the durability of vorasidenib’s benefit in delaying disease progression and deferring more intensive interventions such as radiotherapy or chemotherapy. In lower-grade glioma, where preserving long-term cognitive function and quality of life is a central goal, delaying chemoradiotherapy may be clinically meaningful. The data continue to support vorasidenib’s role as an important treatment option following surgery in appropriately selected patients with IDH-mutant disease.
This content has been developed independently by Touch Medical Media for touchONCOLOGY in collaboration with Dr Rimas Lukas. Views expressed are the speaker’s own and do not necessarily reflect the views of Touch Medical Media.
Disclosure: Rimas Lukas is a consultant for Merck and Novocure. He has received grant/research support from BMS and is a member of the advisory board for Merck and Novocure. He has received honoraria/honorarium from EBSCO, Elsevier and Medlink Neurology. He is a Speaker’s Bureau participant with Merck and Novocure.
Cite: Neuro-oncology at ASCO 2026: What did we learn? touchONCOLOGY. 14th June 2026.
Editor: Sophie Nickelson, Editorial Director
