Article
Comparison of stereotactic interstitial brachytherapy (IBT) using 125iodine seeds with LINAC radiosurgery for the treatment of singular cerebral metastases
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Published: | May 20, 2009 |
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Objective: Radiosurgery is commonly accepted for the treatment of small (<3cm) singular cerebral metastases. Scarce reports suggested interstitial brachytherapy (IBT) by stereotactically guided implantation of 125iodine seeds for treatment of cerebral metastases especially when histology was requested, tumor size exceeded 3 cm and/or microsurgical removal as well as WBRT was no option. In the presented study both methods were compared for the first time with respect to survival and local disease control. Furthermore, possible prognostic factors for survival were evaluated.
Methods: For this retrospective, single centre study we considered all patients treated with either radiosurgery using the linear accelerator (LINAC-RS) or IBT (125iodine, 50Gy surface dose applied over 42 days) for singular cerebral metastasis. Kaplan-Meier curves were used for calculation of survival and Cox regression to investigate local recurrence and prognostic factors (age, gender, RPA classification, KPS, prior treatment, histology, morphology, volume and localization of the metastasis as well as time span between first diagnosis and appearance of cerebral disease less/more than 12 months).
Results: 142 patients treated with LINAC-RS were compared to 77 patients undergoing IBT. Epidemiological and disease related features were distributed almost equally in both groups. Neither median survival (LINAC-RS vs. IBT= 7.1 vs. 8.0 months) nor local disease control rate (91%) showed significant differences. Younger age (<50 years), higher KPS (>70), absence of systemic disease, RPA Class 1, solid morphology and disease history of more than 12 months were correlated (highly) significantly (p<0.05 to p< 0.001) with better survival for the entire population. These prognostic factors did not differ between both treatment modalities.
Conclusions: Comparable outcome results demonstrate that stereotactic interstitial brachytherapy (IBT) can be considered as an alternative procedure to radiosurgery (LINAC) for the treatment of singular cerebral metastasis. However, being more invasive, indications for IBT have to be selected and possible advantages of either method have to be further elucidated.