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Helical Tomotherapy for Brain Metastases: Dosimetric Evaluation of Treatment Plans and Early Clinical Results

2008; SAGE Publishing; Volume: 7; Issue: 6 Linguagem: Inglês

10.1177/153303460800700602

1533-0346

Natsuo Tomita, Takeshi Kodaira, Hiroyuki Tachibana, Tatsuya Nakamura, Rie Nakahara, Haruo Inokuchi, Yuta Shibamoto,

Meningioma and schwannoma management

The purpose of this study was to evaluate the feasibility and treatment plans of intensity-modulated radiation therapy using helical tomotherapy (HT) for brain metastases. Twenty-three patients with 1 to 4 brain metastases were treated with H T. In combination with whole-brain radiotherapy ( simultaneous plans), metastatic lesions, and the whole brain were treated with 50 Gy and 30 Gy, respectively, in 10 fractions, with a simultaneous integrated boost technique. In patients treated for brain metastases alone ( focal plans), metastatic lesions were treated with 35 or 37.5 Gy in 5 fractions. The treatment plans were compared regarding the conformation number (CN) and homogeneity index (HI), and differences in these indexes between simultaneous and focal plans were examined by Student's t-test. Seven and 16 patients were treated with simultaneous plans and focal plans, respectively. The mean ± SD of CN and HI values were 0.75 ± 0.13 and 0.063 ± 0.042, respectively, for simultaneous plans, and 0.73 ± 0.12 and 0.052 ± 0.023, respectively, for focal plans. The CN and HI between the two plans were not significantly different. Response rates in 13 patients with follow-up imaging were approximately 90% for both plans and the local control rate at 1 year was 69%. One patient with a huge tumor (34.0 cc) and WHO performance status 3 treated with focal plans experienced severe headache, requiring prolongation of the treatment time, and died at 8 days after completion of treatment. The exact cause of deterioration was uncertain as no radiological investigation was performed in this patient. No late complications were observed during follow-up periods up to 20 months. HT is a viable non-invasive technique for treatment of brain metastases and achieves high accuracy in terms of dose conformity and homogeneity.