Fractionated stereotactic body radiation therapy in the treatment of primary, recurrent, and metastatic lung tumors: The role of positron emission tomography/computed tomography-based treatment planning

Purpose: The aim of this study was to assess the outcomes of patients treated with stereotactic body radiation therapy (SBRT) in patients with primary, recurrent, or metastatic lung lesions, with a focus on positron emission tomography (PET)/computed tomography (CT)-based management. Patients and Methods: Fifty-one patients with primary stage I non-small-cell lung cancer (NSCLC; n = 26), recurrent lung cancer after definitive treatment (n = 12), or solitary lung metastases (n = 13) were treated with SBRT between 2005 and 2007. Patients were treated with the CyberKnife (R) Robotic Radiosurgery System with Synchrony (TM) respiratory tracking. A dose of 60 Gy was delivered in 3 fractions. All patients had CT or PET/CT performed at approximately 3-month intervals after treatment. Results: The median follow-up was 12 months. Local control at median follow-up was 85% in patients with stage I NSCLC, 92% in patients with recurrent lung cancer, and 62% in the patients with solitary lung metastasis. Analysis of the 28 patients with pre- and post-treatment PET/CT scans demonstrated that those with stable disease (n = 4) had a mean standardized uptake value (SUV) decrease of 28%, partial responders (n = 11) had a decrease of 48%, and patients with a complete response (n = 11) had a decrease of 94%. Patients with progressive disease (n = 2) had an SUV decrease of only 0.4%. Only 2 patients (7%) who had reduced fluorodeoxyglucose avidity later progressed locally. No correlations were found between pretreatment SUV and tumor response, disease progression, or survival. Overall 1-year survival rates were 81%, 67%, and 85% among the patients with primary NSCLC, recurrent lung cancer, and solitary lung metastases, respectively. Conclusion: Stereotactic body radiation therapy with CyberKnife (R) is an effective treatment for patients with medically inoperable recurrent or metastatic lung cancer. Positron emission tomography/CT is valuable in staging, planning, and evaluating treatment response and might predict long-term outcome.