CyberKnife high-dose fractionated stereotactic radiosurgery with tumor tracking: An effective non-surgical treatment alternative for single small peripheral lung tumors

Abstract

18125 Background: We report preliminary outcomes using CyberKnife radiosurgery with tumor tracking to treat small (<4 cm) peripheral inoperable stage I lung cancers and single pulmonary metastases. Methods: Enrollment of eligible pts began in July 2004. Prior conventional thoracic irradiation and the incorporation of systemic therapy were permitted. Fiducials (3–5) were placed near tumors under CT guidance. Pts received 45–60 Gy in 3 equal 1–2 hour fractions delivered over a 5–9 day period. Results: The median follow-up period of survivors was 12 months (range = 3–24 months). A total of 24 lesions were treated, 15 clinical stage I lung cancers and 9 single lung metastases. Four patients had prior conventional thoracic radiation (17%) and 6 patients received systemic therapy in conjunction with radiosurgery (25%). Two received systemic doses of platinum based doublet chemotherapy, 3 received gefitinib and 1 received sunitinib. Pneumothorax was a complication of fiducial placement in 7 pts, requiring tube thoracostomy in 4. All pts completed treatment with few acute side effects. No unexpected additional toxicities were noted with systemic therapy except for one pt who developed Grade III radiation pneumonitis while receiving gefitinib. A second pt with Grade III radiation pneumonitis had prior extensive conventional thoracic radiation. All tumors responded to treatment at 3 months as seen by a decrease in gross tumor volume. At 12 months 14 CT scans were evaluable. Four lesions responded completely (33%), 2 exhibited a partial response and the remaining 8 were obscured by radiation fibrosis corresponding to the high-dose irradiated volume (57%). Local progression was seen in only 2 single lung metastases at 10 and 12 months. There have been no regional lymph node failures. Four patients have died, 1 of progressive metastatic disease and 3 of comorbid illnesses. Conclusion: CyberKnife high-dose fractionated stereotactic radiosurgery with tumor tracking is an effective well-tolerated treatment option for small peripheral lung tumors, both primary and metastatic. The integration of systemic therapy appears feasible but needs to be further evaluated in clinical trials. No significant financial relationships to disclose.