CyberKnife® Radiosurgery for Stage I Lung Cancer: Results at 36 Months

Abstract PURPOSE The aims of this study were to determine if image-guided robotic stereotactic radiosurgery by CyberKnife® Radiosurgery System using ablative radiation doses achieves acceptable local control in medically inoperable patients with early non–small-cell lung cancer (NSCLC) and to evaluate disease-free survival, toxicity, and failure. CyberKnife® can deliver the prescribed dose by using many different angles converging on the target, with real-time target tracking through a combined orthogonal radiograph imaging and optic motion tracking system (Synchrony®). MATERIALS AND METHODS A review of treatment details and outcomes for 59 patients, ranging in age from 51 years to 96 years, with 61 tumors with histologically proven cancers treated by image-guided robotic stereotactic radiosurgery at the CyberKnife Center of Miami between March 2004 and March 2007 is presented. Target localization and respiratory movement compensation were accomplished using a single fiducial marker placed within the tumor, and the X-SightTM and Synchrony® systems. Total doses ranged from 15 Gy to 67.5 Gy delivered in 1-5 fractions with an equivalent dose range of 24-110 Gy normalized treatment dose in 2 Gy fractions (α/β = 20 Gy). RESULTS Four patients with stage 1A NSCLC and 2 patients with stage 1B NSCLC had persistent or recurrent disease. All patients tolerated the radiosurgery well, fatigue being the main side effect. Of the 59 patients treated, 51 (86%) were still alive at 1-33–month follow-up. Eight patients have died, 2 of diseases other than cancer progression. CONCLUSION The results indicate that the delivery of precisely targeted ablative radiation doses with surgical precision to limited treatment volumes of lung tumors in a hypofractionated fashion is feasible and safe. Image-guided robotic stereotactic radiosurgery of lung tumors with CyberKnife® achieves excellent rates of local disease control with limited toxicity to surrounding tissues and, in many cases, might be curative for patients for whom surgery is not an option.