Intensity-modulated radiotherapy in high-grade gliomas: Clinical and dosimetric results

Journal Article · Wed Mar 01 04:00:00 EST 2006 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2005.0· OSTI ID:20793361

Narayana, Ashwatha ^[1]; Yamada, Josh ^[1]; Berry, Sean ^[2]; Shah, Priti B.S. ^[1]; Hunt, Margie ^[2]; Gutin, Philip H ^[3]; Leibel, Steven A ^[4]

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1. Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
2. Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
3. Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)
4. Stanford University Cancer Center, Stanford, CA (United States)

Purpose: To report preliminary clinical and dosimetric data from intensity-modulated radiotherapy (IMRT) for malignant gliomas. Methods and Materials: Fifty-eight consecutive high-grade gliomas were treated between January 2001 and December 2003 with dynamic multileaf collimator IMRT, planned with the inverse approach. A dose of 59.4-60 Gy at 1.8-2.0 Gy per fraction was delivered. A total of three to five noncoplanar beams were used to cover at least 95% of the target volume with the prescription isodose line. Glioblastoma accounted for 70% of the cases, and anaplastic oligodendroglioma histology (pure or mixed) was seen in 15% of the cases. Surgery consisted of biopsy only in 26% of the patients, and 80% received adjuvant chemotherapy. Results: With a median follow-up of 24 months, 85% of the patients have relapsed. The median progression-free survival time for anaplastic astrocytoma and glioblastoma histology was 5.6 and 2.5 months, respectively. The overall survival time for anaplastic glioma and glioblastoma was 36 and 9 months, respectively. Ninety-six percent of the recurrences were local. No Grade IV/V late neurologic toxicities were noted. A comparative dosimetric analysis revealed that regardless of tumor location, IMRT did not significantly improve target coverage compared with three-dimensional planning. However, IMRT resulted in a decreased maximum dose to the spinal cord, optic nerves, and eye by 16%, 7%, and 15%, respectively, owing to its improved dose conformality. The mean brainstem dose also decreased by 7%. Intensity-modulated radiotherapy delivered with a limited number of beams did not result in an increased dose to the normal brain. Conclusions: It is unlikely that IMRT will improve local control in high-grade gliomas without further dose escalation compared with conventional radiotherapy. However, it might result in decreased late toxicities associated with radiotherapy.

• OSTI ID: 20793361
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 64; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BIOPSY
BRAIN
CHEMOTHERAPY
COLLIMATORS
GLIOMAS
HISTOLOGY
NERVES
PATIENTS
RADIATION DOSES
RADIOTHERAPY
SPINAL CORD
SURGERY
SURVIVAL TIME
TOXICITY