Treatment of stage I lung cancer in high-risk and inoperable patients: SBRT vs. RFA vs. sublobar resection.

Abstract

www.annalscts.com Background Although surgical resection for early stage lung cancer is the mainstay of treatment, many patients are inoperable at the time of presentation due to either disseminated disease or medical comorbidities (1). Novel strategies are currently being developed to treat early-stage non-small cell lung cancer (NSCLC) in this expanding population of highrisk and inoperable patients. Stereotactic body radiotherapy (SBRT) modifies traditional radiation techniques to provide a high-dose per fraction of radiation to the tumor which is administered over a few fractions. This allows for effective tumor ablation with preservation of the surrounding tissue due to steep dose gradients. Radiofrequency ablation (RFA) utilizes CT-guided placement of a radiofrequency-emitting probe. As frictional heat energy from the probe is transferred to the tumor, cancer cells undergo coagulation necrosis. In an effort to expand the population of operable patients, many groups are currently exploring the use of sublobar resection to treat early stage tumors. Early evidence suggests that sublobar resection may provide satisfactory oncologic outcomes while avoiding the morbidity of standard lobectomy in patients with poor pulmonary reserve (2). Three major clinical trials have been developed to investigate the use of these different modalities to treat early stage lung cancer in inoperable or high-risk patients. A recently published trial, RTOG 0236, is a North American phase II trial of SBRT in patients with stage I NSCLC deemed inoperable by a surgeon or a pulmonologist. The study showed a local control rate of 90.6% at three years, and disease-free survival and overall survival at three years were 48.3% and 55.8%, respectively (3). ACOSOG Z4032 is a phase III randomized controlled trial that compared sublobar resection to sublobar resection with brachytherapy for the treatment of stage I NSCLC. Thirty- and 90-day outcomes from this study have recently been published (4). In addition, threeyear results were presented at the 2013 American Society of Clinical Oncology (ASCO) meeting, showing a similar rate of local recurrence for those treated with sublobar resection (12.8%) versus sublobar resection with brachytherapy (12.5%) (5). Overall survival was comparable between the groups (sublobar resection =71%, sublobar resection with brachytherapy =72%). Lastly, ACOSOG Z4033 is a phase II prospective nonrandomized study examining high-risk patients with stage I NSCLC treated with RFA. This study has completed accrual, but survival and recurrence data have not yet matured. We conducted a comparison of selection criteria and short-term outcomes for these three studies.