Efficacy and Tolerance of Intensity Modulated Radiation Therapy for Skull Base Meningioma

Target volume delineation for radiotherapy of meningiomas: an ANOCEF consensus guideline

PURPOSE

Radiotherapy is, with surgery, one of the main therapeutic treatment strategies for meningiomas. No prospective study has defined a consensus for the delineation of target volumes for meningioma radiotherapy. Therefore, target volume definition is mainly based on information from retrospective studies that include heterogeneous patient populations. The aim is to describe delineation guidelines for meningioma radiotherapy as an adjuvant or definitive treatment with intensity-modulated radiation therapy and stereotactic radiation therapy techniques. This guideline is based on a consensus endorsed by a multidisciplinary group of brain tumor experts, members of the Association of French-speaking Neuro-oncologists (ANOCEF).

MATERIALS AND METHODS

A 3-step procedure was used. First, the steering group carried out a comprehensive review to identify divergent issues on meningiomas target volume delineation. Second, an 84-item web-questionnaire has been developed to precisely define meningioma target volume delineation in the most common clinical situations. Third, experts members of the ANOCEF were requested to answer. The first two rounds were completed online. A third round was carried out by videoconference to allow experts to debate and discuss the remaining uncertain questions. All questions remained in a consensus.

RESULTS

Limits of the target volume were defined using visible landmarks on computed tomography and magnetic resonance imaging, considering the pathways of tumor extension. The purpose was to develop clear and precise recommendations on meningiomas target volumes.

CONCLUSION

New recommendations for meningiomas delineation based on simple anatomic boundaries are proposed by the ANOCEF. Improvement in uniformity in target volume definition is expected.

Multimodal therapy of cavernous sinus meningioma: Impact of surgery and 68Ga-DOTATATE PET-guided radiation therapy on tumor control and functional outcome

BACKGROUND

Functional preservation in patients with WHO grade I meningioma involving the cavernous sinus (CSM) is crucial for long-term tumor control. Concise data on the functional outcome of an interdisciplinary, multimodal treatment are scarce. We analyzed functional outcome and tumor control in CSM patients following maximal safe resection (MSR), fractionated stereotactic radiotherapy (FSRT), or combination of them, retrospectively.

METHODS

Patients with WHO grade I CSM treated between 2003 and 2017 were included. Prior to FSRT, a 68Ga-DOTATATE PET/CT was performed for radiation planning. Progression-free survival (PFS) was analyzed using Kaplan-Meier method and log-rank test was performed to test differences between groups. Visual function was analyzed at baseline and follow-up.

RESULTS

Eighty-five patients were included. MSR alone was performed in 48 patients (group A), MSR followed by FSRT in 25 patients (group B), and FSRT alone in 12 patients (group C). Intracranial tumor volumes were higher in A and B compared to C (median 9.2/10.8/4.3 ccm for A/B/C, P = .023). Median follow-up was 47/46/45 months and PFS at 5 years 55.7%, 100%, and 100% in A/B/C, respectively (P < .001). Optic nerve compression was more common in A (91.7%) and B (84.0%) than C (16.7%), P < .001. Post-therapeutic new onset or deterioration of double vision was observed in 29% (A), 17% (B), and 0% (C).

CONCLUSION

Personalized treatment strategies for CSM are essential to control space-occupying or functionally compromising lesions. The additional potential side effect of radiotherapy seems to be justified under the aspect of longer tumor control with low functional risk. Without space-occupying effect of CSM, FSRT alone is reasonably possible.