Response to “Is post-operative radiotherapy of any benefit after R0 resection for N2 disease?”
Letter to the Editor

Response to “Is post-operative radiotherapy of any benefit after R0 resection for N2 disease?”

Cliff G. Robinson1, Aalok P. Patel2, Todd DeWees1, Daniel Morgensztern3, Jeffrey D. Bradley1, Varun Puri2

1Department of Radiation Oncology, 2Department of Surgery, Division of Cardiothoracic Surgery, 3Department of Medicine, Division of Medical Oncology, Washington University School of Medicine, St. Louis, Missouri, USA

Correspondence to: Cliff G. Robinson. Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, Box 8224, St. Louis, MO 63017, USA. Email: crobinson@radonc.wustl.edu.

Submitted Aug 24, 2015. Accepted for publication Aug 25, 2015.

doi: 10.3978/j.issn.2218-6751.2015.08.12


We thank Drs Cerfolio and Estes (1) for their comments in regard to our recently published analysis from the National Cancer Data Base (NCDB) exploring the utility of post-operative radiotherapy (PORT) in completely resected N2 non-small cell lung cancer (NSCLC) treated with adjuvant chemotherapy (2). As they note, while the strength of such a multi-institutional database lies in its numbers (in this case, more than 4,000 patients), there is an expected loss of data fidelity and granularity. For example, in our analysis we had a limited ability to explore questions of lymph node station involvement, number of nodes, or completeness of lymph node sampling due to incomplete or completely missing data. As such, we could not control for these variables in our multivariate modeling. However, with respect to questions of lymph node involvement or sampling, it would be expected that those patients with less favorable features (incomplete dissection, more lymph node involvement, etc.,) would be more likely to receive PORT. It if were possible to account for this likely stacking of less favorable patients in the PORT group, it seems possible that we may have seen an even larger benefit to PORT. Nonetheless, such an imbalance could not reverse the survival curves, and therefore we believe our overall conclusions remain sound. Additionally, we appreciate Dr. Cerfolio and Estes’ kind comments regarding the importance of our analysis in the absence of randomized data, and echo our support for randomized trials such as Lung ART.


Acknowledgements

None.


Footnote

Conflicts of Interest: The authors have no conflicts of interest to declare.


References

  1. Cerfolio RJ, Estes JH. Is post-operative radiotherapy of any benefit after R0 resection for N2 disease? Transl Lung Cancer Res 2015;4:665-6.
  2. Robinson CG, Patel AP, Bradley JD, et al. Postoperative radiotherapy for pathologic N2 non-small-cell lung cancer treated with adjuvant chemotherapy: a review of the National Cancer Data Base. J Clin Oncol 2015;33:870-6. [PubMed]
Cite this article as: Robinson CG, Patel AP, DeWees T, Morgensztern D, Bradley JD, Puri V. Response to “Is post-operative radiotherapy of any benefit after R0 resection for N2 disease?”. Transl Lung Cancer Res 2015;4(5):667. doi: 10.3978/j.issn.2218-6751.2015.08.12