New UW Health Re-irradiation Technique Helps Recurrent Glioma Patients
Patients diagnosed with certain types of brain tumors face an unsettling prognosis. In spite of the continued evolution of surgical and chemotherapeutic approaches to treating patients with low- and high-grade gliomas, most patients suffer a recurrence. Unfortunately, their therapeutic options are limited.
Although radiotherapy is a key component in initially managing glioma patients, up until now repeating radiotherapy is limited by potential toxicities. Re-irradiation using conventional techniques has shown only modest palliative and survival benefits. This emphasizes the crucial importance of assessing neurotoxicity and quality of life when considering possible patients.
Using dose rate modulated radiotherapy, Steven Howard, MD, PhD, radiation oncologist with the UW Carbone Cancer Center, developed a unique re-treatment approach designed to minimize toxicity for patients with recurring gliomas.
"Offering this new radiotherapy technique to patients who have no other treatment options has shown both dramatic radiographic responses and significant clinical improvement, with no apparent acute or late neurologic toxicities."
In conventional radiotherapy, a dose is delivered rapidly, resulting in daily treatment times of only a few minutes. Howard's research showed this time interval was too short for most biological repair processes to be clinically relevant. By lowering the effective dose-rate and increasing the time the daily dose is delivered, Howard and his team showed that repair during irradiation becomes possible.
Delivering the reduced dose-rate in a pulsed manner separated by a fixed time interval resulted in repair of radiotherapy-induced cellular damage in normal neural tissues that was more efficient and greater than that seen in malignant glioma cells.
Howard, an associate professor of Human Oncology in the UW School of Medicine and Public Health, has used this re-irradiation technique, called pulsed reduced dose-rate external beam radiotherapy to re-treat recurrent gliomas in patients who have received prior radiotherapy.
He says, "Although strictly palliative in nature, re-irradiation using pulsed reduced dose-rate radiotherapy potentially prolongs life for our patients and ameliorates neurologic symptoms." "Preliminary results suggest this technique is effective even in glioblastoma patients who have progressed after bevacizumab therapy. This is noteworthy; these are patients who have not responded to any type of chemotherapy in clinical trials. An ongoing clinical protocol at the UW addresses this patient population."
For more information about pulsed reduced dose-rate external beam radiotherapy, or ongoing glioblastoma clinical trials, contact Dr. Howard at the UW Cancer Center at (608) 263-8500, or through Cancer Connect at (800) 622-8922.