Background: There is no consensus on the management of incidental meningiomas. The literature on long-term growth dynamics is sparse and the natural history of these tumors remains to be illuminated.
Methods: We prospectively assessed long-term tumor growth dynamics and survival rates during active monitoring of 62 patients (45 female, mean age 63.9 years) harboring 68 tumors. Clinical and radiological data were obtained every 6 months for 2 years, annually until 5 years, then every second year.
Results: The natural progression of incidental meningiomas during 12 years of monitoring was growth (P < .001). However, mean growth decelerated at 1.5 years and became insignificant after 8 years. Self-limiting growth patterns were seen in 43 (63.2%) tumors, non-decelerating in 20 (29.4%) and 5 (7.4%) were inconclusive due to ≤ 2 measurements. Decelerating growth persisted once established. Within 5 years, 38 (97.4%) of 39 interventions were initiated. None developed symptoms prior to intervention. Large tumors (P < .001) involving venous sinuses (P = .039) grew most aggressively. Since inclusion 19 (30.6%) patients have died of unrelated causes and 2 (3%) from grade 2 meningiomas.
Conclusion: Active monitoring seems a safe and appropriate first-line management of incidental meningiomas. Intervention was avoided in > 40% with indolent tumors in this cohort. Treatment was not compromised by tumor growth. Clinical follow-up seems sufficient beyond 5 years if self-limiting growth is established. Steady or accelerating growth warrant monitoring until they reach a stable state or intervention is initiated.
Keywords: asymptomatic meningioma; incidental meningioma; natural history; prospective study; volumetric tumor growth.
© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Neuro-Oncology and the European Association of Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.