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Long term survival with stereotactic ablative radiotherapy (SABR) versus thoracoscopic sublobar lung resection in elderly people: national population based study with propensity matched comparative analysis

BMJ 2016; 354 doi: https://doi.org/10.1136/bmj.i3570 (Published 08 July 2016) Cite this as: BMJ 2016;354:i3570
  1. Subroto Paul, director of thoracic surgery1,
  2. Paul C Lee, chief of thoracic surgery2,
  3. Jialin Mao, research associate3,
  4. Abby J Isaacs, senior research analyst3,
  5. Art Sedrakyan, professor and director3
  1. 1Department of Cardiothoracic Surgery, RWJ Barnabas Health System, West Orange, NJ, USA
  2. 2Department of Thoracic Surgery, New York Presbyterian Hospital/Queens, NY, USA
  3. 3Department of Healthcare Policy and Research, Weill Cornell Medical College and New York Presbyterian Hospital/New York, 402 E 67th Street, New York, NY, 10065, USA
  1. Correspondence to: A Sedrakyan ars2013{at}med.cornell.edu
  • Accepted 24 June 2016

Abstract

Objectives To compare cancer specific survival after thoracoscopic sublobar lung resection and stereotactic ablative radiotherapy (SABR) for tumors ≤2 cm in size and thoracoscopic resection (sublobar resection or lobectomy) and SABR for tumors ≤5 cm in size.

Design National population based retrospective cohort study with propensity matched comparative analysis.

Setting Surveillance, Epidemiology, and End Results (SEER) registry linked with Medicare database in the United States.

Participants Patients aged ≥66 with lung cancer undergoing SABR or thoracoscopic lobectomy or sublobar resection from 1 Oct 2007 to 31 June 2012 and followed up to 31 December 2013.

Main outcome measures Cancer specific survival after SABR or thoracoscopic surgery for lung cancer.

Results 690 (275 (39.9%) SABR and 415 (60.1%) thoracoscopic sublobar lung resection) and 2967 (714 (24.1%) SABR and 2253 (75.9%) thoracoscopic resection) patients were included in primary and secondary analyses. The average age of the entire cohort was 76. Follow-up of the entire cohort ranged from 0 to 6.25 years, with an average of three years. In the primary analysis of patients with tumors sized ≤2 cm, 37 (13.5%) undergoing SABR and 44 (10.6%) undergoing thoracoscopic sublobar resection died from lung cancer, respectively. The cancer specific survival diverged after one year, but in the matched analysis (201 matched patients in each group) there was no significant difference between the groups (SABR v sublobar lung resection mortality: hazard ratio 1.32, 95% confidence interval 0.77 to 2.26; P=0.32). Estimated cancer specific survival at three years after SABR and thoracoscopic sublobar lung resection was 82.6% and 86.4%, respectively. The secondary analysis (643 matched patients in each group) showed that thoracoscopic resection was associated with improved cancer specific survival over SABR in patients with tumors sized ≤5 cm (SABR v resection mortality: hazard ratio 2.10, 1.52 to 2.89; P<0.001). Estimated cancer specific survival at three years was 80.0% and 90.3%, respectively.

Conclusions This propensity matched analysis suggests that patients undergoing thoracoscopic surgical resection, particularly for larger tumors, might have improved cancer specific survival compared with patients undergoing SABR. Despite strategies used in study design and propensity matching analysis, there are inherent limitations to this observational analysis related to confounding, similar to most studies in healthcare of non-surgical technologies compared with surgery. As the adoption of SABR for the treatment of early stage operable lung cancer would be a paradigm shift in lung cancer care, it warrants further thorough evaluation before widespread adoption in practice.

Footnotes

  • Contributors: SP was responsible for the study concept and design and was assisted by PL and AS. AS, JM, and AJI acquired the data. All authors analyzed and interpreted the data. SP, PCL, and AS drafted the manuscript. All authors critically revised the manuscript for important intellectual content. AJI, JM, and AS were responsible for the statistical analysis. AS supervised the study and is guarantor.

  • Funding: AS received funding from the US FDA for establishing the MDEpiNet Science and Infrastructure Centre that enables device and surgery outcomes investigations.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organization for the submitted work; no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: The study was approved by the Weill Cornell Medical College institutional review board (protocol No 1308014193).

  • Data sharing: Technical appendix and statistical code available from the corresponding author; dataset available from National Cancer Institution http://healthcaredelivery.cancer.gov/seermedicare/obtain/.

  • Transparency: The lead authors (study guarantors) affirm that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained

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