PURPOSE: To report pulmonary function test changes one year following robotic radiosurgery for high-risk surgical patients with Stage I non-small cell lung cancer (NSCLC)
METHODS: High-risk surgical patients with biopsy-proven stage I NSCLC measuring 5 cm or less in maximum diameter were evaluated. Three-to-five gold fiducial markers were implanted in or near tumors under CT guidance to serve as targeting references. Gross tumor volumes (GTVs) were contoured using lung windows; the margins were expanded by 5 mm to establish the planning treatment volume (PTV). Treatment plans were designed using hundreds of pencil thin beams. Doses delivered to the PTV 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 the CyberKnife system with tumor tracking. Full pulmonary function tests were completed just prior to treatment and at one year follow-up.
RESULTS: Forty patients (median age 76) with a median maximum tumor diameter of 2.6 cm (range, 1.4-5.0 cm) and a median post-bronchodilator percent predicted FEV1 of 48% (range, 21 - 111%) were treated over a five year period and followed for a minimum of one year. A mean dose of 50 Gy was delivered to the PTV over a 3 to 13 day period (median, 7 days). The 30-Gy isodose contour extended a mean distance of 1.9 cm from the GTV. At median potential follow-up of 44 months, the 3-year Kaplan-Meier locoregional control, overall survival and disease free survival estimate were 91%, 75% and 70%, respectively. At one year, there was a decrease of 6 percent predicted FEV1 and 7 percent predicted DLCO.
CONCLUSIONS: Robotic radiosurgery is an effective treatment for stage I NSCLC. The treatment is well tolerated and results in a minimal decrease in FEV1 and DLCO.
CLINICAL IMPLICATIONS: Robotic radiosurgery allows for effective treatment of patients with stage I NSCLC who otherwise would not tolerate alternative treatment regimens.
DISCLOSURE: Sean Collins: Consultant fee, speaker bureau, advisory committee, etc.: Accuray
Brian Collins: Consultant fee, speaker bureau, advisory committee, etc.: Accuray
The following authors have nothing to disclose: Daniel Casey, Eric Oermann, Viola Chen, Saloomeh Vahdat, Simeng Suy, Xia Yu, Deepa Subramaniam, Filip Banovac, Eric Anderson
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