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TOPLINE:

Molecular risk score plus extent of surgical resection predicted outcomes in grade 1 meningiomas, a new analysis found. Postoperative radiotherapy also improved local tumor control in recurrent, high-risk cases following subtotal resection.

METHODOLOGY:

• World Health Organization (WHO) grade 1 meningiomas generally have low recurrence rates after gross total resection but relatively higher rates after subtotal resection. In addition, a significant proportion of clinically low-risk cases harbor high-risk molecular characteristics, suggesting that combining surgical and molecular data could help guide postoperative therapy.
• Researchers conducted a retrospective analysis of 210 patients with WHO grade 1 meningioma (median age at diagnosis, 57 years; 138 women) who had available DNA methylation profiles. Patients underwent gross total (84.3%) or subtotal (15.7%) resection without immediate adjuvant radiotherapy.
• An institutionally established integrated molecular score was calculated for each patient, using DNA methylation, chromosomal losses of 1p, 6q, and/or 14q, and WHO grade. Patients were classified as low (n = 177), intermediate (n = 29), or high (n = 4) risk.
• The primary outcome was local progression-free survival (PFS), measured from surgical resection to tumor progression in patients who underwent surgery alone and from completion of radiotherapy to tumor progression in patients who relapsed and received radiotherapy. The median follow-up duration was 42 months.

TAKEAWAY:

• At 3 years, local PFS was 93.0% after gross total resection and 69.3% after subtotal resection; gross total resection was associated with significant improvement in local PFS (hazard ratio [HR], 0.195; P < .001).
• Among patients in the low-risk group, 3-year PFS was 94.3% after gross total resection and 77.4% after subtotal resection. The 3-year PFS rates were 85.9% after gross total resection and 40.0% after subtotal resection in patients with intermediate/high scores.
• Overall, 34 recurrences occurred (16.2%); 29 patients underwent re-resection (gross total re-resection, n = 8 and subtotal re-resection, n = 21). Among patients with subtotal re-resection, 18 received postoperative radiotherapy at a median 2 months. Local PFS improved to 88.9% after postoperative radiotherapy in 10 patients with intermediate- and high-risk scores, “tentatively” suggesting a benefit of intensified adjuvant treatment, the authors wrote. All toxicities were grade 2 or lower; moderate fatigue and focal alopecia were the most common side effects.
• To rule out the possibility that the findings were specific to the prediction model, tumors were reclassified using the University of California San Francisco molecular grouping: 40% Merlin-intact, 39.5% immune-enriched, and 20.5% hypermitotic. When paired with resection extent, 3-year local PFS was 93.1% after gross total resection vs 73.2% after subtotal resection in the Merlin-intact/immune-enriched group and 92.3% vs 50.0% in the hypermitotic group, confirming that “both molecular models can consistently predict the risk of local recurrence.”

IN PRACTICE:

“Our study suggests that postopera­tive [radiotherapy] should be considered after subtotal resection of recurrent — and may be discussed in newly diagnosed — molecularly higher-risk WHO grade 1 meningiomas,” the authors concluded.

SOURCE:

This study, led by Maximilian Y. Deng, MD, Heidelberg University Hospital, Heidelberg University, Heidelberg, Germany, was published online in Neuro-Oncology.

LIMITATIONS:

Clinical and molecular data were collected retrospectively, and treatment decisions were based on multidisciplinary consensus and patient preferences. In recurrent cases, molecular testing was done on the recurrent tumor tissue, but it is unclear whether molecular alterations during tumor relapse may lead to changes in molecular risk classification.

DISCLOSURES:

Deng reported receiving support from the Medical Faculty of Heidelberg, the Else Kröner Fresenius Foundation, and the German Consortium for Translational Cancer Research. Some authors reported receiving honoraria or speaker fees and having other ties with various sources. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.