Parenchymal damage in the territory of the anterior choroidal artery following supraophthalmic intracarotid administration of CDDP for treatment of malignant gliomas

Strategies for Improved Intra-arterial Treatments Targeting Brain Tumors: a Systematic Review

Conventional treatments for brain tumors relying on surgery, radiation, and systemic chemotherapy are often associated with high recurrence and poor prognosis. In recent decades, intra-arterial administration of anti-cancer drugs has been considered a suitable alternative drug delivery route to intravenous and oral administration. Intra-arterial administration is believed to offer increasing drug responses by primary and metastatic brain tumors, and to be associated with better median overall survival. By directly injecting therapeutic agents into carotid or vertebral artery, intra-arterial administration rapidly increases intra-tumoral drug concentration but lowers systemic exposure. However, unexpected vascular or neural toxicity has questioned the therapeutic safety of intra-arterial drug administration and limits its widespread clinical application. Therefore, improving targeting and accuracy of intra-arterial administration has become a major research focus. This systematic review categorizes strategies for optimizing intra-arterial administration into five categories: (1) transient blood-brain barrier (BBB)/blood-tumor barrier (BTB) disruption, (2) regional cerebral hypoperfusion for peritumoral hemodynamic changes, (3) superselective endovascular intervention, (4) high-resolution imaging techniques, and (5) others such as cell and gene therapy. We summarize and discuss both preclinical and clinical research, focusing on advantages and disadvantages of different treatment strategies for a variety of cerebral tumor types.

Principles of pharmacotherapy

This chapter will review the challenges in pharmacotherapy in primary brain tumors that include the presence of the blood-brain barrier, a blood-tumor barrier, active drug efflux pumps, and high plasma protein binding of agents. The approaches to improve the delivery of drugs to the brain will be discussed. Often the management of brain tumors involves the use of corticosteroids and enzyme-inducing antiseizure medications that can have significant drug interactions that may impact the efficacy or toxicity of drugs used to treat these patients. Various techniques used to assess drug distribution to the brain will be reviewed.

Is intra-arterial chemotherapy useful in high-grade gliomas?

Low delivery of common chemotherapeutic drugs to the brain is considered to be a major obstacle for obtaining durable disease control in patients with high-grade gliomas. Intra-arterial drug injection after selective catheterization of cerebral arteries has been performed in some small clinical trials in order to achieve higher drug concentration in the tumor while minimizing systemic exposure. We reviewed the results in terms of response and toxicity from studies with intra-arterial administration of nitrosoureas and platinum derivatives, as well as the principal aspects and perspectives of the new strategy of blood-brain barrier disruption with osmotic agents or bradykinin analogs. No superiority of intra-arterial chemotherapy over its intravenous counterpart has been demonstrated so far and although the incidence of serious neurotoxicity is reduced, the risk of untoward acute complication still contraindicates internal carotid or vertebral artery catheterization for chemotherapy administration outside the setting of well-controlled clinical trials.

Intraarterial chemotherapy for brain tumors by using a spatial dose fractionation algorithm and pulsatile delivery

PURPOSE

To evaluate the cause of complications in intraarterial chemotherapy for brain tumors and validate a dosage algorithm based on arterial territory.

MATERIALS AND METHODS

Four hundred sixty-two procedures were performed in 113 patients. Technique included pulsatile infusion of a chemotherapeutic agent. Dosage was calculated per hemisphere and divided per arterial territory according to a spatial dose fractionation algorithm based on the vascular territories of major cerebral arteries: middle cerebral artery, 60%; anterior cerebral artery, 20%; posterior cerebral artery, 15%; and perforator arteries, 5%. Hospital charts of all patients were retrospectively reviewed for complications, with specific attention given to the angiograms to determine a cause. Then, subgroup analysis of the chemotherapy protocol with the largest patient population was performed to evaluate predictors of complications.

RESULTS

Six (1.3%) complications were asymptomatic; 12 (2.6%), transient neurologic; three (0.6%), permanent minor neurologic; three (0.6%), permanent major neurologic; and 32 (7.0%), seizures. In the subgroup analysis, the hemispheric dose administered according to the algorithm was strongly predictive of seizure and neurologic deficit.

CONCLUSION

Neurotoxicity of intraarterial cerebral chemotherapy can be minimized by using pulsatile injection and the described spatial dose fractionation algorithm.

Cytotoxic chemotherapy: advances in delivery, pharmacology, and testing

Adjuvant treatment of malignant gliomas, the most common types of primary brain tumors, with intravenous (iv) chemotherapy has not significantly improved survival for patients with these forms of cancer. A major factor in the failure of iv chemotherapy is the blood-brain barrier (BBB), a physiologic impediment to the delivery of cytotoxic chemotherapeutic drugs to the central nervous system (CNS). Intra-arterial and intrathecal infusion, blood-brain barrier disruption, high-dose chemotherapy, intratumoral administration, and convection-enhanced delivery are methods developed to overcome the BBB. Although some of these methods may increase the local concentration-time profile, improvement in clinical outcomes has yet to be definitively established. New methods for assessment of drug delivery to the brain tumor will assume increasing importance in the study of new cytotoxic chemotherapeutic drugs for these types of cancer. Pharmacokinetic studies are critical components of these clinical trials and allow assessment of drug delivery to the CNS and brain tumor. Additionally, pharmacokinetic studies will remain an important component of early clinical trials, particularly for identifying significant drug interactions involving the various supporting medications that are typically used in this patient population.