What is the current status of Stereotactic body radiotherapy for stage I non-small cell lung cancer?

Non-small cell lung cancer, if detected at early stage, is a disease with high probability for cure. However, the treatment in clinical practice is highly dependent on the co-morbidities of the patient, the performance status and age. A relevant proportion especially of the elderly patient population remains untreated despite the dismal prognosis of untreated stage I NSCLC with 5 year cancer specific survival (CSS) of only 16% (1,2). Conventionally fractionated radiotherapy has been the treatment of choice for medically inoperable patients: however, outcome is suboptimal with 5 year CSS ranging between 13% and 39% (3); most importantly, local disease recurrence is the most frequent site of failure, not systemic metastases (4). CSS is excellent after lobectomy ranging between 100% and 57.6% depending on the size of the primary tumor (5). Despite a randomized trial demonstrated inferior outcome of sublobar resection compared to lobectomy (6), sublobar resection is practiced especially in high-risk patients aiming at preservation of pulmonary function (7). Wedge resection seems to be insufficient even for small tumors whereas segmentectomy results in promising CSS if the tumor size is below 3cm (5,8).