Analyse de la toxicité précoce des traitements par Cyberknife® des cancers pulmonaires et résultats préliminaires

Purpose. - High-dose robotic stereotactic irradiation can be achieved with high precision using the Cyberknife (R) M system equipped with the Synchrony (R) respiratory tracking device. Cyberknife (R) irradiation can overcome some limitations of conventional radiotherapy including errors due to breathing motion and patient setup. High dose levels are of interest for tumours that have shown a dose-response relationship including lung tumours. We reviewed the treatments and outcomes for the first French patients with lung tumours treated at the Cyberknife (R) centre of Nice. Patients and methods. - Thirty four patients were treated between November 2006 and November 2007 at the Cyberknife (R) centre of Nice, Centre Lacassagne, France. Thirty had untreated primary lung cancer, 4 had colorectal metastasis to the lung. We evaluated the feasibility and reliability of fiducial placement, toxicity and early outcomes. Objective tumour response was assessed on thoracic CT scan every three months. Results. - There was no grade 3-4 toxicity. Toxicity (11 %) mainly consisted of grade 1-2 asthenia. Crude overall tumour response rate was 96% for all assessable patients and 91% at 3 and 6 months, respectively. The use of one fiducial ensured minimal toxicity (no grade III pneumothorax) while allowing reliable tumour tracking as shown by the low infield failure rate (no geographic miss). Diagnostic procedure was performed during fiducial placement when required. Conclusion. - Early toxicity and tumour control rates from this population suggest that the use of a unique fiducial for a Cyberknife treatment was safe and effective for the treatment of selected primary and secondary lung tumours. This strategy is corroborated by similar control rates in the literature. Longer follow-up are awaited. (C) 2008 Elsevier Masson SAS. Tous droits reserves.