PURPOSE: Both robotic radiosurgery and wedge resection for peripheral stage I non-small cell lung cancer (NSCLC) are designed to eradicate lung tumors with tight 1 to 2 cm margins in order to preserve functioning lung tissue. A recent study (Grills et al., 2010. J Clin Oncol.;28:928-35) reported superior tumor control with stereotactic body radiation therapy (SBRT), but 3-year overall survival was significantly better for wedge resection at near 80%. Here we report robotic radiosurgery results for inoperable patients with peripheral stage I NSCLC and compare them to contemporary wedge resection outcomes.
METHODS: Thirty-two inoperable patients with biopsy-proven peripheral stage I NSCLC measuring less than 4 cm in maximum diameter were evaluated. PET/CT imaging was completed for staging. Gross tumor volumes (GTVs) were contoured using lung windows; the margins were expanded by 5 mm to establish the planning treatment volume (PTV). Doses delivered to the gross tumor ranged from 42-60 Gy in 3 fractions. The 30-Gy isodose contour extended at least 1 cm from the GTV to eradicate microscopic disease. Treatments were delivered utilizing robotic radiosurgery with tumor tracking. Clinical examination and PET/CT imaging were completed at 6-month intervals following treatment.
RESULTS: Patients (median age 76 years) with a median post-bronchodilator percent predicted FEV1 of 48% (range, 21-111%) were treated over a 5-year period. A mean dose of 50 Gy was delivered. The 30-Gy isodose contour extended an average of 1.8 cm from the GTV. At a median 33.5 months, the 3-year Kaplan-Meier locoregional control and overall survival estimates were 90% and 76%, respectively.
CONCLUSION: Locoregional control and overall survival estimates following robotic radiosurgery are similar to recently published wedge resection results. Randomized trials comparing robotic radiosurgery with wedge resection for high-risk patients with peripheral stage I NSCLC are necessary to confirm equivalence.
CLINICAL IMPLICATIONS: Robotic radiosurgery is an attractive treatment option for high-risk patients with peripheral stage I NSCLC.
DISCLOSURE: Brian Collins, Consultant fee, speaker bureau, advisory committee, etc. Accuray speaker bureau, Dr. Brian Collins and Dr. Eric Anderson; No Product/Research Disclosure Information