A dosimetric comparison between CyberKnife and tomotherapy treatment plans for single brain metastasis.

PURPOSE: Radiosurgery (RS) is a well-established treatment in selected patients with brain metastasis. The aim of this study is to compare the differences between CyberKnife (CK) and TomoTherapy (HT) treatment plans of RS of single brain metastasis (BM) to define when HT should be used in cases beyond Cyberknife-when both systems are readily available for the radiation oncologist. METHODS AND MATERIALS: Nineteen patients with single brain metastasis treated with CK were re-planned for radiosurgery using TomoTherapy Hi-ART system. Two planning approaches have been used for TomoTherapy plans: the classical one (HT) and the improved conformity (icHT) that produces dose distributions more similar to those of RS plans. PTV coverage, Conformity Index (CI), Paddick Conformity Index (nCI), Homogeneity Index (HI), Gradient Index (GI), and beam on time of CK, HT, and icHT plans were evaluated and compared. RESULTS: A good coverage was found for CK, HT, and icHT plans. A difference between mean HI of CK and icHT plans was observed (p = 0.007). Better dose gradients compared to both icHT and HT modalities were observed in CK plans. icHT modality showed improved mean CI respect to HT modality, similar to that obtained in CK plans. CONCLUSIONS: CK plans show higher conformity and lower GI than icHT and HT plans. TomoTherapy demonstrates the advantage of being a device capable to reach different clinical objectives depending on the different planning modality employed. CyberKnife and TomoTherapy are both optimal RS devices, the choice to use one over another has to be clinically guided.

Cyberknife stereotactic radiosurgery for the re-irradiation of brain lesions: a single-centre experience.

PURPOSE: The aim of our study was to retrospectively evaluate the feasibility and clinical benefit of cyberknife stereotactic radiosurgery (CSRS) in patients treated at Florence University for recurrent, pre-irradiated brain lesions. MATERIALS AND METHODS: Thirteen patients were retreated with cyberknife. Mean age was 47.1 years (range 33-77 years). Karnofsky performance status ranged from 60 to 100 (median 80). Eleven (84.6%) out of 13 patients had metastatic lesions: four (36.4%) had primary lung, three (27.2%) had primary breast cancer and four (36.4%) other types of solid malignancies. Two (15.4%) out of 13 patients had recurrent of glioblastoma. RESULTS: In terms of compliance with CSRS, the majority of patients did not develop any acute side effects. However, two (15.4%) out of 13 patients developed acute grade 2 toxicity requiring an increase of steroid medication. At the time of the last follow-up, response rates were as follows: complete response in one case (16.6%), partial response in three (50%) and stable disease in two (33.4%). CONCLUSIONS: Re-irradiation with CSRS is a feasible and effective option for pre-irradiated, recurrent brain lesions to obtain clinical benefit without excessive acute toxicity.

Stereotactic body radiotherapy for cardiac and paracardiac metastases: University of Florence experience.

PURPOSE: This study sought to evaluate acute toxicity and local control in patients who underwent extracranial stereotactic body radiation therapy (SBRT) for paracardiac and cardiac metastatic lesions, defined as such when located at a maximum distance of 1 cm from the heart or inside its parenchyma. MATERIALS AND METHODS: Between January 2009 and May 2011, 16 patients with paracardiac and cardiac lesions were treated with SBRT. For dose specification, in 15 of 16 patients, the prescription dosage was 36 Gy in three fractions (70% isodose). In one patient, the target lesion was inside the heart, and the prescription dosage was 30 Gy in three fractions (70% isodose). RESULTS: Regarding response to stereotactic radiotherapy, we recorded one (6%) complete response (CR), six (37%) partial responses (PR), five (32%) stable disease (SD) and four (25%) local failures. Median interval to local failure was 5.2 (range, 3-12) months. The cause of death was distant progression of disease in all four patients. Compliance to treatment was excellent; no patient developed cardiological symptoms or electrocardiographic abnormalities, even months after SBRT. CONCLUSIONS: Results of our retrospective study indicate that SBRT represents a safe and effective treatment option for patients with cardiac and paracardiac metastases.