Métastases cérébrales : quelle prise en charge en 2012 ?

[Differential diagnosis of local tumor recurrence or radionecrosis after stereotactic radiosurgery for treatment of brain metastasis]

Magnetic resonance imaging (MRI) is a method of choice for follow-up of irradiated brain metastasis. It is difficult to differentiate local tumour recurrences from radiation induced-changes in case of suspicious contrast enhancement. New advanced MRI techniques (perfusion and spectrometry) and amino acid positron-emission tomography (PET) allow to be more accurate and could avoid a stereotactic biopsy for histological assessment, the only reliable but invasive method. We report the case of a patient who underwent surgery for a single, left frontal brain metastasis of a breast carcinoma, followed by adjuvant stereotactic radiotherapy in the operative bed. Seven months after, she presented a local change in the irradiated area on the perfusion-weighted MRI, for which the differentiation between a local tumour recurrence and radionecrosis was not possible. PET with 2-deoxy-((18)F)-fluoro-D-glucose (FDG) revealed a hypermetabolic lesion. After surgical resection, the histological assessment has mainly recovered radionecrosis with few carcinoma cells. The multimodal MRI has greatly contributed to refine the differential diagnosis between tumour recurrence and radionecrosis, which remains difficult. The FDG PET is helpful, in favour of the diagnosis of local tumour recurrence when a hypermetabolic lesion is found. Others tracers (such as carbon 11 or a fluoride isotope) deserve interest but are not available in all centres. Stereotactic biopsy should be discussed if any doubt remains.

Stereotactic radiotherapy for large solitary brain metastases

PURPOSE

To assess effectiveness and toxicity levels of stereotactic radiation therapy without whole brain radiation therapy in patients with solitary brain metastases larger than 3cm.

PATIENTS AND METHODS

Between June 2007 and March 2009, 12 patients received fractionated stereotactic radiation therapy and 24 patients underwent stereotactic radiosurgery. For the fractionated stereotactic radiation therapy group, 3×7.7Gy were delivered to the planning target volume (PTV); median volume and diameter were 29.4 cm(3) and 4.4cm, respectively. For the stereotactic radiosurgery group, 14Gy were delivered to the PTV; median volume and diameter were 15.6 cm(3) and 3.7cm, respectively.

RESULTS

Median follow-up was 218 days. For the fractionated stereotactic radiation therapy group, local control rates were 100% at 360 days and 64% at 720 days; for the stereotactic radiosurgery group, rates were 58% at 360 days and 48% at 720 days (P=0.06). Median survival time was 504 days for the fractionated stereotactic radiation therapy group and 164 days for the stereotactic radiosurgery group (P=0.049). Two cases of grade 2 toxicity were observed in the fractionated stereotactic radiation therapy group, and 6 cases of grade 1-2 toxicity, in the stereotactic radiosurgery group.

CONCLUSIONS

This study provides data to support that fractionated stereotactic radiation therapy without whole brain radiation therapy with a margin dose of 3 fractions of 7.7Gy for treatment of solitary large brain metastases is efficient and well-tolerated. Because of the significant improvement in overall survival, this schedule should be assessed in a randomized trial.

[Clinical aspects of brain metastases from nasopharyngeal carcinoma]

Metastasis to the central nervous system, either through a hematogenous route or through the cerebrospinal fluid, is extremely rare in nasopharynx cancer. We aim to expose clinical aspects, therapeutic features and prognosis of nasopharyngeal carcinoma with brain metastases. We retrospectively reviewed the medical history of about 420 patients with nasopharyngeal carcinoma treated during 17 years at the university hospital of Sfax (Tunisia). Among them, three patients had brain metastasis. We excluded patients with direct extension to the brain. Tumours of the nasopharynx were locally advanced. The first patient had brain metastases at the initial diagnosis. The two other patients had brain metastases at 10 and 16 months during the follow-up. Ocular signs were the symptoms. Lesions were unique in two patients. Synchronous bone metastases were recorded in the three cases. All patients had whole brain radiation therapy and palliative chemotherapy. All patients had a progression of the disease and died. Brain metastases in nasopharynx cancer represent a rare event. Prognosis is poor, depending on age, surgical excision and synchronous metastases. Survival does not exceed 6 months.

[Brain metastases from breast cancer]

Breast cancer is the second leading cause of brain metastases and account for 15 % of metastatic breast cancer patients. Several patient- and tumor-related characteristics have been identified as risk factors for developing brain metastases. Treatment is based on local and/or systemic therapies, tailored to breast cancer brain metastases-specific prognostic factors. This article is an update on the current knowledge of the incidence, prognosis and prognostic factors, treatment and perspectives in brain metastases from breast cancer.

[Cognitive evaluation during brain radiotherapy in adults: a simple assessment is possible]

Brain irradiation can be used for the treatment of cancers in different protocols: focal radiotherapy, whole brain radiotherapy, with or without additive dose on the tumour. Different modalities (conformational, stereotactic radiosurgery) can be used for curative or prophylactic treatment. Brain radiotherapy leads to cognitive deterioration with subcortical profile. This cognitive deterioration can be associated to radiation-induced leukoencephalopathy on brain MRI. Taking into account radiation induced cognitive troubles is becoming more important with the prolonged survival allowed by treatment improvement. Concerning low-grade gliomas, radiation-induced cognitive troubles appear about 6 years after treatment and occur earlier when the fraction dose is important. Primitive cerebral lymphoma treatment can induce cognitive troubles in 25 to 30% surviving patients. These deficits are more frequent in elderly patients, leading to radiotherapy delay in those patients. Patients treated for brain metastasis often have cognitive impairment before radiotherapy (until 66%), this pretreatment impairment is related to global survival. The use of conformational radiation therapy, particularly with hippocampal sparing is conceptually interesting but has not proved its efficiency for cognitive preservation in clinical trials yet. Stereotactic radiation therapy could be an interesting compromise between metastatic tumoral volume reduction and cognitive preservation. Taking care of radiotherapy induced cognitive troubles is a challenge. Before considering its treatment and prevention, we need to elaborate a way of detecting them using a reliable and easy way. CSCT, a computerized test whose execution needs 90 seconds, could be used before treatment and during the clinical follow-up by the patient's oncologist or radiotherapist. If the patient's performance reduces, he can be oriented to a neurologist in order to perform fuller evaluation of its cognitive capacities and be treated if necessary.