[Spinals and paraspinals tumors treated by CyberKnife: feasibility and efficacy]

Stereotactic radiotherapy using the CyberKnife has become a key treatment in the multidisciplinary management of secondary tumours, as well as primary benign or malignant tumours located within or adjacent to vertebral bodies and the spinal cord. The aim of this treatment is to improve local control and clinical response, including previously irradiated cases.

In this study, we present the first patients treated with CyberKnife between December 2006 and December 2007 for spinal or paraspinal tumours. The primary aim was to assess the feasibility and tolerance of stereotactic radiotherapy using the CyberKnife. Secondary aims were to establish the short-term local control, to calculate the local progression-free survival and overall survival. Clinical examination and imaging procedures were performed every three months. Response was assessed according to RECIST criteria.

During that period, 16 patients were treated with CyberKnife. Thirteen patients had been pre-treated, three of whom had received spinal cord doses considered to be maximal. Three patients did not receive previous irradiation. The median age was 59 (36-74). The most frequent symptoms were pain (n = 8) and motor weakness (n = 4). The median dose was 30 Gy (16-50). The median number of fractions was 3 (1-5). No patient developed acute myelitis. Three patients developed acute reaction. Overall survival at 18 months was 72.4%, with a mean survival of 18.2 months (95% CI: 15.4-20.9). Local progression-free survival at 18 months was 58.4%, with a mean value of 16.9 months (95% CI: 13.6-20.2).

The use of stereotactic radiotherapy with CyberKnife represents a major progress in the management of paraspinal tumours. The main advantages are better sparing of the spinal cord and the possibility of increasing the dose to the tumour target volume.