Volume not number of metastases: Gamma Knife radiosurgery management of intracranial lesions from an Australian perspective.

BACKGROUND AND PURPOSE: To assess the response of the first cohort of patients treated with Gamma Knife radiosurgery in Australia. MATERIALS AND METHODS: A prospectively collected cohort of 180 patients with intracranial metastases from different primaries was treated between August 2010 and July 2017. Survival was calculated using the Kaplan-Meier's method. Cox regression was used for multivariate analysis. RESULTS: Currently 141 patients (78.3%) have died of their disease. The median survival for the group as a whole was 9.2 months, with observed differences resulting from the volume of tumor burden (11.4 months for volumes <3.2 cm3 to 5.16 months for volume >9.1 cm3). Overall 2-year survival was 20.7%. CONCLUSION: Results from the first Gamma Knife radiosurgery center in Australia showed that the treatment is feasible and effective, consistent with the international experience. For patients with larger numbers of intracranial metastases, the total volume of the intracranial burden may be of more significance in predicting outcomes. While there appeared to be a difference in survival by histologic origin, this could be related to concurrent systemic immunotherapy available for certain tumors.

Current strategies in the surgical management of cerebral metastases: an evidence-based review.

Metastatic tumours are the most common form of cerebral neoplasm, occurring in up to 40% of patients with systemic cancer. Although the presence of metastatic disease portends limited survival, aggressive management of cerebral metastases is vital to preventing death from neurological causes and prolonging functional independence. Due to advancement in neurosurgical techniques and the advent of stereotactic radiosurgery as a non-operative alternative, current decision making for selecting the appropriate local treatment often results in clinical equipoise. In addition, the traditional blanket application of whole brain radiation has come under scrutiny as new evidence regarding the deleterious neurocognitive effects of ionizing radiation emerges. The completion of a series of randomized studies comparing the efficacy of surgery, radiosurgery, whole brain radiotherapy and various combined approaches for cerebral metastases in recent years has shed important light on addressing some of these issues. The focus of this review is to summarize the key findings and outline a practical approach for the management of cerebral metastases.

A cluster of nocardial brain abscesses.

BACKGROUND: Nocardia species are aerobic Gram-positive bacteria that are ubiquitous in the environment. Infection usually occurs through inhalation or direct cutaneous inoculation of the organism. It has been reported that infection is more common in warm, dry climates. Cerebral nocardiosis is an uncommon clinical entity, representing only 2% of all cerebral abscesses. It is an illness associated with significant morbidity and mortality. CASE DESCRIPTIONS: We report 4 cases of nocardial brain abscesses presenting to TCH, Australia, within a 1-year period. All 4 cases occurred in men without any significant underlying immunocompromise. In 3 of the cases, the diagnosis was only established after craniotomy. All cases were given prolonged antimicrobial therapy. After more than 8 months of follow-up, there have been no deaths or treatment failures. There has been only one other case of nocardial brain abscess at TCH over the past 15 years. We review the current literature on cerebral nocardiosis. CONCLUSION: Nocardial brain abscesses are uncommonly encountered at our institution. This cluster of 4 cases over a 1-year period has therefore led us to postulate that the severe drought may be aiding in the transmission of the bacteria. The cases also emphasize the propensity of nocardial infections to mimic other conditions, particularly malignancy, which may lead to delays in appropriate surgical treatment and antimicrobial therapy. The diagnosis requires a high clinical index of suspicion, with early tissue and microbiological diagnosis. Prolonged antimicrobial therapy is required to prevent relapse of the infection.