From the Guidelines
The majority of coincidental meningiomas, approximately 60-70%, remain stable over many years of follow-up, with only a small percentage showing significant growth. When managing coincidental meningiomas, the approach typically involves observation with regular imaging surveillance rather than immediate intervention, as outlined in guidelines such as those from the Journal of the National Comprehensive Cancer Network 1. Key considerations in the management of these tumors include:
- Tumor size: Small meningiomas (< 30 mm) are often observed, especially if asymptomatic, while larger ones (≥ 30 mm) may require surgery if accessible, followed by radiation therapy (RT) if they are WHO grade 3c or if there's incomplete resection for WHO grade 1/2 tumors 1.
- Symptomatology: Symptomatic meningiomas, regardless of size, usually require surgical intervention if accessible, followed by RT for WHO grade 3c tumors or consideration of RT for incomplete resection of WHO grade 1/2 tumors 1.
- Growth rate: The median growth rate for meningiomas is about 4 mm per annum, but significant growth (>1 cm/year) can prompt a reevaluation of the management plan. Given the slow growth rate of many meningiomas and the risks associated with surgical intervention, a conservative approach with regular monitoring is often preferred for asymptomatic, incidentally discovered meningiomas. This approach allows for the identification of tumors that may require more aggressive management due to growth or the development of symptoms, while minimizing unnecessary interventions and their associated risks for patients with stable, asymptomatic lesions.
From the Research
Management Approach for Coincidental Meningiomas
The management approach for coincidental meningiomas involves several factors, including the risk of complications from surgery, the possibility of malignancies, and the age and medical condition of the patient 2.
Growth Patterns of Incidental Meningiomas
Incidental meningiomas can fall into one of three main growth patterns: no growth, linear growth, or exponential growth 2.
Percentage of Coincidental Meningiomas that Enlarge on Follow-up
- Approximately 35.4% of incidental meningiomas were found to grow during follow-up, resulting in a 75% 15-year growth rate by life-table statistics 3.
- The growth rates were similar in smaller (<2 cm) and larger tumors, while calcified tumors grew at a lower rate, although this difference was not statistically significant 3.
Treatment Options
Treatment options for meningiomas include surgical intervention, stereotactic radiosurgery (SRS), and fractionated stereotactic radiotherapy (SRT) 4, 5, 6.
- SRS is typically used for smaller meningiomas that are considered inoperable or for patients who prefer not to undergo surgery 4.
- SRT is useful for larger meningiomas or those closely approximating critical structures, such as the optic chiasm and brainstem 5.
- A systematic review and meta-analysis found that SRT carries a better radiographic tumor control rate and a lower incidence of post-treatment symptomatic worsening and symptomatic edema compared to SRS 6.