Stereotactic radiotherapy of histologically proven inoperable stage I non-small cell lung cancer: patterns of failure.

Abstract Background and purpose To report patterns of failure of stereotactic body radiation therapy (SBRT) in inoperable patients with histologically confirmed stage I NSCLC. Materials and methods Ninety-two inoperable patients (median age: 75years) with clinically staged, histologically proven T1 ( n =31) or T2 ( n =61), N0, M0 non-small cell lung cancer (NSCLC) were included in this study. Treatment consisted of 3–5 fractions with 7–15Gy per fraction prescribed to the 60% isodose. Results Freedom from local recurrence at 1, 3 and 5years was 89%, 83% and 83%, respectively. All 10 local failures were observed in patients with T2 tumors. Isolated regional recurrence was observed in 7.6%. The crude rate of distant progression was 20.7%. Overall survival at 1, 3, and 5years was 79%, 38% and 17% with a median survival of 29months. Disease specific survival at 1, 3, and 5years was 93%, 64% and 48%. Karnofsky performance status, T stage, gross tumor volume and tumor location had no significant impact on overall and disease specific survival. SBRT was generally well tolerated and all patients completed therapy as planned. Conclusion SBRT for stage I lung cancer is very well tolerated in this patient cohort with significant cardiopulmonal comorbidity and results in excellent local control rates, although a considerable portion develops regional and distant metastases.