Early results of CyberKnife image-guided robotic stereotactic radiosurgery for treatment of lung tumors

Objective: To determine if image-guided robotic stereotactic radiosurgery (IGR-SRS) by CyberKnife achieves acceptable local control in resectable but medically inoperable patients with non-small cell lung cancer (NSCLC) or pulmonary metastasis, and to evaluate control rates and toxicity. Methods: Treatment details and outcomes were reviewed for 95 patients (age range 33-96 years) with 136 histologically proven cancers treated by IGR-SRS at the CyberKnife Center of Miami between March 2004 and March 2007. Tumor volumes ranged from 1.2 cc to 338 cc. Targeting was accomplished using combined skeletal alignment and real-time tracking via fiducials placed within the tumor. Total doses ranged from 15 to 67.5 Gy delivered in 1 to 5 fractions. Results: Of the 95 patients treated, 78 (82%) are still alive at 1 to 36 months post-treatment. Nineteen patients have died, four from disease other than cancer progression. All patients but one achieved at least partial response to treatment and tolerated radiosurgery well. For the majority of our patients, fatigue had been the main side effect. Conclusions: The delivery of precisely targeted high radiation doses with surgical precision to lung tumors in a hypo-fractionated fashion is feasible and safe. Image-guided robotic stereotactic radiosurgery (IGR-SRS) of lung tumors with the CyberKnife achieves excellent rates of local disease control with limited toxicity to surrounding tissues, and in many cases may be curative for patients for whom surgery is not an option.