[Role of radiotherapy in the treatment of cerebral meningiomas]

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.

Surveillance, Epidemiology, and End Results database and propensity score matching analysis of postoperative radiotherapy for non-malignant meningioma: A retrospective cohort study

BACKGROUND

The clinical effect of postoperative radiotherapy (PORT) in non-malignant meningioma (NMM) has not been well explored.

METHODS

A total of 8629 patients with NMM (surgery alone group: n = 7716, postoperative radiotherapy group: n = 913) were obtained from the Surveillance, Epidemiology, and End Results database. Patient profiles were matched by 1:1 propensity score matching (PSM). Logistic regression analysis was performed to identify factors associated with PORT versus surgery alone (SA). Univariate and multivariate Cox regression analyses determined prognostic variables with overall survival (OS) in NMM. Subgroup analyses were performed with Cox proportional hazards regression models.

RESULTS

All the SA (n = 7716) and PORT (n = 913) groups were included. Women with PORT (66.3%) and SA (70.9%) were almost twice as likely as men, and tumors with benign behaviors in the SA group were almost seven times more frequent than those with malignant characteristics. We explored the demographic, clinical characteristics, and prognostic factors in NMM. Laterality, surgery, tumor size, diagnosis year, age, and tumor behavior were associated with PORT versus SA. Patients treated with PORT had better OS than those treated with SA (p = 0.03). After PSM, PORT remained comparable to SA (hazard ratio 0.56, 95% confidence interval 0.35-0.88, p = 0.013). In the subgroup analysis of PORT treatment, borderline malignant behavior increased the death risk by 23%, while other variables did not have a significant clinical benefit (p > 0.05).

CONCLUSIONS

Borderline malignant behavior should be considered seriously, and the PORT regimen should be actively implemented for patients with benign meningiomas.

Case of a WHO Grade II Atypical Meningioma in a 16-Year-Old Female

Meningiomas have a high frequency of occurrence as primary intracranial tumors. We report the case of a 16-year-old female who presented with a three-week history of persistent headache, vomiting, and photophobia. Imaging studies revealed the presence of a meningioma in the right occipital lobe of the brain. The patient underwent surgical resection, and histopathological analysis confirmed the diagnosis of an atypical WHO grade 2 meningioma. The patient experienced a significant improvement in her symptoms postoperatively and had no evidence of recurrence on follow-up imaging. This case highlights the importance of considering meningioma in the differential diagnosis of relatively young patients presenting with chronic headaches, and the favorable prognosis associated with atypical WHO grade 2 meningiomas following complete surgical resection.

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

Purpose

The purpose of this study was to evaluate the efficacy and tolerance of normofractionated stereotactic radiation therapy (RT) and intensity modulated RT with helical tomotherapy for skull base meningioma.

Methods and Materials

Between January 2009 and 2014, 46 patients with skull base meningioma were treated with normofractionated intensity modulated RT in stereotactic conditions (50%) or with helical tomotherapy (50%). Most of the lesions were localized in the cavernous sinus (59%). The mean planning target volume was 47.2 mL (range, 1.1-223 mL).

Results

After treatment, 5 lesions exhibited a partial response radiologically and 39 lesions were stable. At the time of treatment, 35 patients were symptomatic with a mean of 2 symptoms per patient. The most frequent symptoms were visual impairment (41%), cranial nerve dysfunction (20%), and headache (16%). The median follow-up time was 42 months (range, 10-76 months). After RT, 71% of patients exhibited an improvement of at least 1 symptom with a median interval of 15.6 months (range, 5.3-30.5 months). The most frequent improved symptoms were cranial nerve deficits (47%), visual impairment (45%), and headache (42%).The clinical response was correlated with the clinical target volume (CTV) margin (P = .06), extended clinical follow-up time (P = .004), and larger planning target volume (P = .05) by univariate analysis. Taking in account correlation factors, in the multivariate analysis, only CTV was a favorable significant factor of clinical improvement (P = .049; hazard ratio: 5 95%; confidence interval, 1.1-28). We observed 3 cases of trigeminal nerve dysfunction at 4.2, 5.7, and 24.6 months; 2 cases of visual disturbance at 10.1 and 24 months; 2 cases of neurocognitive disorders at 12.9 and 35.2 months; and 1 case of stroke at 20.3 months.

Conclusions

RT for skull base meningiomas is an effective and safe treatment, leading in most cases to clinical improvement. The addition of a CTV margin to meningioma volume improved the symptoms of patients.

[Skull base meningioma: Clinical and radiological efficacy based on a quantitative volumetric analysis]

PURPOSE

To date, no correlation has been found between clinical and radiological efficacy after irradiation of skull base meningiomas. However, the evaluation of the radiological response was most often made by questionable methods that may have underestimated the radiological effectiveness of radiotherapy. The objective of this work is to verify this hypothesis by quantitative volumetric analysis.

MATERIAL AND METHODS

Data from 35 patients treated with either helical tomotherapy (45.7%) or fractionated stereotactic radiotherapy (54.3%) were retrospectively analysed. These were mainly women (94%) aged 59 (43-81) with lesions mainly of the cavernous sinus (60%). There was a median of 2 (1-4) symptoms and the main symptoms were visual impairment (39%), cranial nerve deficits (23.4%) and headaches (17.2%).

RESULTS

Median tumour volume decreased significantly (P<0.05) from 9.6mL (0.3-36.6) to 6.8mL (0.1-26.5) after median follow-up of 44 months (24-77). Sixty-three percent of patients had an improvement of at least one symptom. In univariate analysis, clinical efficacy (P<0.05), radiotherapy technique (P<0.05), tumor topography (P<0.05) and initial tumor volume (P<0.05) were predictive factors for radiological response. In multivariate analysis, only the inverse correlation between radiological response and initial tumor volume remained significant (ρ: -0.47 95% CI -3.2 to 5.7; P<0.05).

CONCLUSION

The quantitative volumetric monitoring demonstrates a major radiological efficiency of radiotherapy. However, no clear correlation between clinical and radiological efficacy was found.

Multimodal Management of Metastatic Malignant Meningiomas: The Role of Radiosurgery in Long-Term Local Control

BACKGROUND

Metastatic meningiomas (MMs) are rare (0.1 of 100 cases). Their treatment requires a multimodal approach, with surgery, radiotherapy, chemotherapy, and radiosurgery, which allows a long-term local control (LC) and an extension of free survival. In this study, the authors performed a review of the literature and reported 2 cases of patients affected by extracranial MMs, with long-term follow-up.

CASE DESCRIPTION

Case 1: A 48-year-old woman was admitted for resection of an extra-axial falx lesion (meningioma G1). After 2 years, the lesion got a local recurrence, resected with a histologic diagnosis of meningioma G3. During the next 9 years, the patient underwent 5 Gamma Knife radiosurgery (GKRS) procedures for local recurrence. At 56 years, she was readmitted for a surgical local recurrence (histologic definition: anaplastic meningioma G3). At the age of 62, the patient underwent a right lobectomy for a lung mass (histologic diagnosis: anaplastic meningioma G3). After that, multiple lesions at soma L5 and adrenal gland were discovered and then monitored. Case 2: A 48-year-old woman was operated for a lesion involving torcular herophili (meningioma G2). After 3 years, a local recurrence requires GKRS combined with tamoxifen. In the next 7 years, she underwent 5 GKRS procedures for local recurrence. The patient also underwent chemotherapy with octreotide. At the age of 61, she discovered multiple lesions in both lungs, liver, and kidney. A hepatic biopsy showed anaplastic meningioma G3. Also this patient does not suffer from any neurologic or clinical deficits.

CONCLUSIONS

LC in malignant meningioma is achievable through a multimodal approach; GKRS makes possible LC, but a novel aspect of these lesions is opened to discussion: the metastases. These reports show that multimodal treatment for MMs is an effective approach with good LC and improvement of overall survival. However, a long survival may allow systemic diffusion of the disease, in particular, when sagittal sinus is involved.

[Base of the skull meningioma: Efficacy, clinical tolerance and radiological evaluation after radiotherapy]

Skull base meningioma leads to functional disturbances, which can significantly alter the quality of life. The optimal management of these lesions, whose goals are neurological preservation and tumour local control, is not yet clearly established. It is widely recognized that the goal of a radical excision should be abandoned despite the advances in the field of microsurgery of skull base lesions. Although less morbid, partial tumour excision would be associated with increased risk of local tumour recurrence. Although discussed both exclusive and adjuvant have proven to be highly successful in terms of clinical improvement and local control. Various radiation techniques have demonstrated their efficacy in the management of this pathology. However, high rates of clinical improvement are in contrast with low rates of radiological improvement. The notion of clinical and radiological dissociation appeared. However, in most of these studies, the analysis of the radiological response could be subject of legitimate criticism. This work proposes to review the local control, the efficacy and the clinical tolerance and the radiological response of the various radiation techniques for the meningioma of the base of the skull and to demonstrate the interest of quantitative volumetric analyses in the follow-up of meningioma after radiotherapy.

[Dosimetry comparison of irradiation with conformal radiotherapy, intensity modulated radiotherapy, conformal radiotherapy in stereotactic conditions and robotic stereotactic radiotherapy for benign brain tumours]

PURPOSE

To compare several techniques in order to determine the best treatment for benign brain tumours.

METHODS AND PATIENTS

A retrospective study was performed for five patients who received 3D-conformal radiotherapy, intensity modulated radiotherapy or CyberKnife(®). These patients had a meningioma, a pituitary tumour, a craniopharyngioma or a neurinoma. In each case, these treatment plans were optimised and compared with the three other dosimetries. Radiobiological or positioning parameters were evaluated, as well as dosimetric parameters, in order to compare treatments with different characteristics.

RESULTS

The dosimetric parameters showed that the choice of treatment seemed to be determined mostly by tumour size, shape and proximity with organs at risk (not tumour localisation). Whereas the results showed no significant deviations with regards to the radiobiological parameters. Therefore, with these parameters, it was difficult to give priority to a treatment.

CONCLUSIONS

With regards to benign brain tumours of medium or large size, intensity modulated radiotherapy seemed the recommended treatment. It enabled to obtain a good ratio between efficacy and toxicity for tumours that are really close to organs at risk. Concerning small benign brain tumours, the CyberKnife(®) was probably the best treatment.

Chondromyxoid fibroma of the skull base: differential diagnosis and radiotherapy: two case reports and a review of the literature

Chondromyxoid fibromas are uncommon tumours mostly arising in long bones of young males. Involvement of the skull base is extremely rare. We describe two new cases of base of the skull chondromyxoid fibromas. The tumours were incompletely excised and irradiated with protons because of the high risk of complications of another surgical procedure. The rationale for proton therapy was based on the intimate relations between the tumour and the organs at risk. Skull base chondromyxoid fibroma is a very rare, slowly growing benign tumour that can cause severe disabilities due to tumour compression of critical structures. Only surgical resection has been shown to be relatively effective. We report two cases of incompletely excised lesions treated by postoperative high-dose radiation including proton therapy with no active disease and complication. Our review of the literature allows us to conclude that histological diagnosis of lesions in this site is a trap for pathologists and that radiotherapy is not contraindicated.

Spot-scanning proton radiation therapy for recurrent, residual or untreated intracranial meningiomas

BACKGROUND AND PURPOSE

To assess the safety and efficacy of spot scanning proton beam radiation therapy (PRT) in the treatment of intracranial meningiomas.

PATIENTS AND METHODS

Sixteen patients with intracranial meningioma (histopathologically proven in 13/16 cases) were treated with PRT between July 1997 and July 2002. Eight patients had skull base lesions. Thirteen patients received PRT after surgery either as adjuvant therapy for incomplete resection (eight patients) or for recurrence (five patients). Three patients received radical PRT after presumptive diagnosis based on imaging. The median prescribed dose was 56 CGE (range, 52.2-64, CGE=proton Gy X 1.1) at 1.8-2.0 CGE (median, 2.0) per fraction. Gross tumor volume and planning target volume ranged from 0.8 to 87.6 cc (median, 17.5) and 4.6-208.1 cc (median 107.7), respectively. Late ophthalmologic and non-ophthalmologic toxicity was assessed using the Subjective, Objective, Management and Analytic scale (SOMA) of the Late Effects of Normal Tissue scoring system and National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE, v3.0) grading system, respectively. The median follow-up time was 34.1 months (range, 6.5-67.8).

RESULTS

Cumulative 3-year local control, progression-free survival and overall survival were 91.7, 91.7 and 92.7%, respectively. No patient died from recurrent meningioma. One patient progressed locally after PRT. Radiographic follow-up (median, 34 months) revealed an objective response in three patients and stable disease in 12 patients. Cumulative 3-year toxicity free survival was 76.2%. One patient presented with radiation induced optic neuropathy (SOMA Grade 3) and retinopathy (SOMA Grade 2) 8.8 and 30.4 months after treatment, respectively. These patients with ophthalmologic toxicity received doses higher than those allowed for the optic/ocular structures. Another patient developed a symptomatic brain necrosis (CTCAE Grade 4) 7.2 months after treatment. No radiation-induced hypothalamic/pituitary dysfunction was observed.

CONCLUSIONS

Spot-scanning PRT is an effective treatment for patient with untreated, recurrent or incompletely resected intracranial meningiomas. It offers highly conformal irradiation for complex-shaped intracranial meningiomas, while delivering minimal non-target dose. Observed ophthalmologic toxicity is dose-related.

Brachytherapy for intracranial meningioma using a permanently implanted iodine-125 seed

PURPOSE

To investigate the response and complications of iodine-125 brachytherapy for the treatment of recurrent and newly diagnosed meningiomas. Clinical cases of 2 patients treated with this method are presented.

MATERIALS AND METHODS

Thirteen patients with primary and recurrent intracranial meningioma were treated by frameless stereotactic implantation of iodine-125 seeds from January 1996 to June 1998. The total dose to decay ranged from 7,000 to 17,000 cGy, with a dose rate of 5-10 cGy/h.

RESULTS

All 11 evaluable patients had a decrease or stabilization in the size of their lesions as detected by MRI during follow-up. There were no acute complications. All patients who received a total dose greater than 10,000 cGy had postoperative radiation necrosis and/or vasogenic edema while only 20% of the patients who received doses of 10,000 cGy or less had radiation changes (p = 0.002).

CONCLUSIONS

MRI-guided stereotactically assisted permanent implantation of iodine-125 seeds seems to be a safe, effective and noncomplicated method for the treatment of primary and recurrent meningiomas for selected patients, when doses are limited to 10,000 cGy.