Helical tomotherapy for brain metastases: dosimetric evaluation of treatment plans and early clinical results.
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 HT. 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.
Tomita
N
N
Department of Radiation Oncology, Aichi Cancer Center Hospital, Nagoya 464-8681, Japan. ntomita@aichi-cc.jp
Kodaira
T
T
Tachibana
H
H
Nakamura
T
T
Nakahara
R
R
Inokuchi
H
H
Shibamoto
Y
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000528:radiation effects; D001932:Brain Neoplasms / Q000532:radiotherapy* / Q000556:secondary*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D018787:Radiation Oncology / Q000379:methods; D011874:Radiometry / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D016896:Treatment Outcome