According to a recent article published in the British Journal of Cancer, vaccines made in part from a patient’s cancer cells following surgery appear to be an effective approach for some patients with relapsed glioma.
Gliomas are the most common type of cancerous brain tumors in adults. Malignant gliomas refer to a group of cancers that develop in glial cells, which are the most abundant cells of the nervous system. These cells provide many supportive functions that facilitate the majority of processes conducted by neurons (cells that transmit impulses between the brain, spinal column and nerves). There are several types of malignant gliomas, including anaplastic astrocytoma (AA), anaplastic oligodendroglioma (AO) and anaplastic mixed oligoastrocytoma (AOA). Gliomas are differentiated by the cancer cells’ appearance under a microscope, with “high-grade” referring to an aggressive type of glioma and “low-grade” referring to a slower growing glioma. The aggressiveness of gliomas are clinically numbered by grade, with grade I being the most slow-growing and grade IV being the most aggressive. Standard treatment for gliomas often consists of surgery, chemotherapy, radiation therapy and/or biologic therapy.
Although the surgical removal of gliomas remains an important treatment component, patients often experience a cancer recurrence. The rates of recurrence are highly dependent upon the type of glioma and the extent of surgical removal; however, even in cases where it appears that all of the cancer has been removed, recurrence rates remain high. This is because microscopic amounts of cancer cells that are undetectable with current screening methods remain in the body following surgery or have already spread to different places in the body or brain. Therefore, research efforts are focused on treatment after surgery in an attempt to destroy any remaining cancer cells and thus, reduce the rates of recurrence.
Vaccines are emerging into the clinical setting in the treatment of various types of cancers. One type of vaccine utilizes components of cancer cells taken from the cancer once it is surgically removed, which are then mixed with a specific type of immune cell from the patient’s body. The concept behind this type of vaccination is that the immune cell, which normally stimulates the immune system against a specific type of cell (bacteria, virus, fungus, etc.), stimulates the immune system to recognize and destroy any cancer cells that may be in the body.
Researchers from Germany recently conducted a clinical trial to evaluate a vaccine utilizing a mixture of patients’ immune cells and components of their cancer cells following surgery in recurrent glioma. This trial included 12 patients; only 6 of them were able to have their cancer completely surgically removed (complete resection). Vaccines were given at weeks 1 and 3 following surgery, and later every 4 weeks, for an overall average of 5 vaccinations per patient. In the 6 patients who were not able to have their cancer completely removed, one patient had a partial disappearance of cancer following the vaccine and one patient achieved disease stabilization. Of the 6 patients who had a complete resection, 2 of these patients (33%) still have no evidence of cancer at approximately 3 years following treatment. The vaccines were well tolerated, with generally mild side effects.
The researchers concluded that patients with recurrent glioma who are able to have a complete resection appear to benefit from vaccines comprised of immune cells and components of the cancer with minimal side effects. Future clinical trials will further evaluate this treatment approach, including the use of vaccine therapy earlier in the course of the disease. Patients with recurrent glioma may wish to speak with their physician about the risks and benefits of participating in a clinical trial further evaluating vaccine therapy or other promising therapeutic approaches. Sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov).
Reference: Rutkowski S, De Vleeschouwer S, Kaempgen E, et al. Surgery and adjuvant dendritic cell-based tumour vaccination for patients with relapsed malignant glioma, a feasibility study. British Journal of Cancer. 2004;91: 1656-1662.