Disease control and ototoxicity using intensity-modulated radiation therapy tumor-bed boost for medulloblastoma.

Abstract

PURPOSE:

We previously reported excellent local control for treating medulloblastoma with a limited boost to the tumor bed. In order to decrease ototoxicity, we subsequently implemented a tumor-bed boost using intensity-modulated radiation therapy (IMRT), the clinical results of which we report here.

PATIENTS AND METHODS:

A total of 33 patients with newly diagnosed medulloblastoma, 25 with standard risk, and 8 with high risk, were treated on an IMRT tumor-bed boost following craniospinal irradiation (CSI). Six standard-risk patients were treated with an institutional protocol with 18 Gy CSI in conjunction with intrathecal iodine-131-labeled monoclonal antibody. The majority of patients received concurrent vincristine and standard adjuvant chemotherapy. Pure-tone audiograms were graded according to National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0.

RESULTS:

Median age was 9 years old (range, 4-46 years old). Median follow-up was 63 months. Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS) rates for standard-risk patients who received 23.4 or 36 Gy CSI (not including those who received 18 Gy CSI with radioimmunotherapy) were 81.4% and 88.4%, respectively, at 5 years; 5-year PFS and OS rates for high-risk patients were both 87.5%. There were no isolated posterior fossa failures outside of the boost volume. Posttreatment audiograms were available for 31 patients, of whom 6%, at a median follow-up of 19 months, had developed Grade 3 hearing loss.

CONCLUSION:

An IMRT tumor-bed boost results in excellent local control while delivering a low mean dose to the cochlea, resulting in a low rate of ototoxicity.

• Authors: William R Polkinghorn, Ira J Dunkel, Mark M Souweidane, Yasmin Khakoo, David C Lyden, Stephen W Gilheeney, Oren J Becher, Amy S Budnick, Suzanne L Wolden
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 81 Issue 3 Pg. e15-20 (Nov 01 2011) ISSN: 1879-355X [Electronic] United States
• PMID: 21481547 (Publication Type: Journal Article)
• Copyright: Copyright © 2011 Elsevier Inc. All rights reserved.

Chemical References

• Antibodies, Monoclonal
• Iodine Radioisotopes

Topics

• Adolescent
• Adult
• Antibodies, Monoclonal (therapeutic use)
• Cerebellar Neoplasms (drug therapy, mortality, radiotherapy)
• Chemotherapy, Adjuvant (methods)
• Child
• Child, Preschool
• Cochlea (radiation effects)
• Cranial Irradiation (methods)
• Disease-Free Survival
• Female
• Follow-Up Studies
• Hearing (physiology, radiation effects)
• Humans
• Iodine Radioisotopes (therapeutic use)
• Male
• Medulloblastoma (drug therapy, mortality, radiotherapy)
• Middle Aged
• New York City
• Radioimmunotherapy (methods)
• Radiotherapy Dosage
• Radiotherapy, Intensity-Modulated (adverse effects, methods)
• Retrospective Studies
• Young Adult