Radiation Therapy Oncology Group (RTOG) trial 93-05 started slowly,
but is now accruing on target, enrolling three patients per month,
says Dr. Luis Souhami, chair of the study. To date, 40 patients
are enrolled in the study.
RTOG 93-05 is evaluating whether radiosurgery can increase local
control and survival of patients with glioblastoma multiforme.
Toxicity and quality of life issues also are end points of the
The current treatment for patients with glioblastoma multiforme
is surgery (if feasible) followed by external beam radiation therapy
and carmustine (BCNU [BiCNU]).
All patients enrolled in RTOG 93-05 will undergo surgery (if feasible),
conventional radiation therapy, and chemotherapy (BCNU). Conventional
radiation therapy will be given at 2 Gy in 30 fractions for a
total dose of 60 Gy in 6 weeks. BCNU (80 mg/m²) will be given
on days 1, 2, and 3 of radiation therapy, then every 2 months
for a total of six cycles.
Half of the patients will be randomized to also undergo radiosurgery,
says Dr. Souhami. The radiosurgery dose is tumor dependent. Patients
with tumors 20 mm or less will receive 21 Gy; patients with tumors
21 mm to 30 mm will be given 18 Gy; and patients with tumors 31
mm to 40 mm will be treated with 15 Gy. Patients with tumors >
40 mm after surgery are not eligible to participate in the study.
Patients undergo radiosurgery before external-beam radiation treatments
Earlier studies have indicated that higher doses of radiation
therapy can increase median survival of these patients, says Dr.
Souhami. "By adding radiosurgery we can give that higher
dose of radiation to the brain while still sparing normal tissue,"