Gliadel Wafer is a specialized medical device used in the focused treatment of certain brain cancers. Its general purpose involves delivering medication directly to the site where a tumor has been removed. This approach aims to address remaining cancer cells within the brain cavity.
Understanding Gliadel Wafer
Gliadel Wafer consists of a biodegradable polymer, specifically polifeprosan 20, which acts as a carrier for the chemotherapy drug carmustine (also known as BCNU). Each sterile, off-white to pale yellow wafer measures approximately 1.45 cm in diameter and 1 mm thick, containing 7.7 mg of carmustine. The carmustine is evenly distributed within the polymer matrix.
When implanted, the wafer slowly releases carmustine directly into the brain cavity over a period of about 21 days, with the majority of the drug released within the first 5 to 7 days. This localized delivery targets residual cancer cells that may remain after surgical removal of a brain tumor, minimizing the systemic exposure to the chemotherapy drug that would occur with intravenous administration. The polymer degrades completely over 6 to 8 weeks, with breakdown products eliminated through urine.
When Gliadel Wafer is Used
Gliadel Wafer is indicated for the treatment of specific aggressive brain tumors. It is used in adults with newly diagnosed high-grade malignant glioma, including glioblastoma multiforme (GBM), as an addition to surgery and radiation therapy. The wafer is also applied in cases of recurrent glioblastoma multiforme following surgical removal of the tumor.
The purpose of using Gliadel Wafer in these contexts is to deliver chemotherapy directly to the area where the tumor was, targeting any microscopic cancer cells that might have been left behind after the main surgical resection. This localized approach helps address the infiltrative nature of these tumors, which often recur near the original tumor bed.
The Implantation Procedure
The Gliadel Wafer is implanted during the same surgical procedure in which the brain tumor is removed. After the neurosurgeon resects the tumor, the wafers are placed directly into this resection cavity. Up to eight wafers can be placed along the walls and floor of the resection cavity.
The wafers are designed to dissolve slowly, releasing the chemotherapy drug over a period of about two to three weeks, meaning they do not need to be removed in a subsequent operation. Post-operative monitoring includes assessing the surgical wound for normal healing and signs of infection.
Managing Potential Reactions
Patients receiving Gliadel Wafer may experience potential reactions, some of which are also common after brain surgery itself. Brain swelling, or cerebral edema, is a common reaction that can occur, sometimes requiring corticosteroids for management. In some cases, persistent brain swelling may even necessitate another surgical procedure to remove the wafers or their remnants.
Seizures are also a possible reaction, with a notable percentage of patients experiencing new or worsening seizures, often within the first five days after surgery. Other potential issues include infections within the brain, such as meningitis, and challenges with wound healing at the surgical site.
Gliadel Wafer’s Role in Treatment Plans
Gliadel Wafer is generally used as part of a broader, multi-modal treatment strategy for brain cancer. It typically supplements other therapies, including surgical removal of the tumor, radiation therapy, and systemic chemotherapy. This integrated approach aims to provide comprehensive management of the disease.
The local delivery of carmustine from the wafer directly into the resection cavity contributes to improving local control of the disease by targeting residual cancer cells. This direct application allows for higher concentrations of chemotherapy at the tumor site than systemic administration. Its use, often in conjunction with radiation and systemic chemotherapy, helps prolong progression-free survival and overall survival for selected patients with high-grade gliomas.