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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Alain J. Poncelet Permission Requests Google Scholar Articles by Poncelet, A. J. Articles by Hanin, F.-X. PubMed Articles by Poncelet, A. J. Articles by Hanin, F.-X. Related Collections Lung - cancer Lung - other Mediastinum Trachea and bronchi

Letters to the Editor

Reply to Chong

^a Department of Cardiovascular and Thoracic Surgery, Cliniques universitaires St-Luc-UCL, Brussels, Belgium
^b Department of Nuclear Medicine, Cliniques universitaires St-Luc-UCL, Brussels, Belgium

Received 3 July 2008; accepted 14 July 2008.

^_* Corresponding author. Address: Cardio-Vascular and Thoracic Surgery Unit, U.C.L. Saint Luc Hospital, Université catholique de Louvain, Avenue Hippocrate 10, B-1200 Brussels, Belgium. Tel.: +32 2 7646107; fax: +32 2 7648960. (Email: Poncelet{at}chir.ucl.ac.be).

Key Words: Non-small cell lung cancer • PET-FDG • SUV • Prognosis • Thoracic surgery

We very much appreciated the remarks and comments from Chong [1] on our recently published results on the prognostic significance of PET-FDG SUVmax in early stage non-small cell lung cancer [2].

In his letter to the editor, Chong has underlined several potential faults with data presentation and analysis that we would like to answer for the sake of clarity even though a peer reviewed statistical analysis did validate the current published study.

Chong rightly stated that our article did not provide the results of the univariate analysis of pre-defined prognostic factors for survival.

None of the following variables reached the level of significance and therefore, were not mentioned in the final revised manuscript: grade of differentiation (HR 2.06; 95%CI [0.98–4.3]), histology (HR 0.53; 95%CI [0.27–1.04]), N status (HR 1.6; 95%CI [0.8–3.24]), sex (HR 1.2; 95%CI [0.57–2.4]).

As suggested by Chong, a multivariate analysis including all variables with a level of significance < or =0.10 was conducted. Again, SUVmax greater than 7.8 was the only significant (p = 0.009) variable with an HR 2.6 (95%CI [1.3–5.4]).

The median survival time was chosen for differentiating groups, but obviously, all Kaplan–Meier survival curves were generated at the same time. The overall survival (OS) at five-year for the SUV_low and the SUV_high groups were 82.2% and 50.2% (log-rank p = 0.001).

The disease-free survival (DFS) at five-year for the SUV_low and the SUV_high groups were 77% and 60.7%, respectively (log-rank p = 0.019).

No cancer-related deaths were present in both SUV groups and we thought this would not bias the analysis. However, as suggested, we here have excluded from all analysis the patients who died of a cancer-unrelated death during the follow-up (n = 21). For this selected subgroup, OS at five-year for the SUV_low and the SUV_high groups were 88.3% and 65.7% (log-rank p = 0.001) and DFS at five-year for the SUV_low and the SUV_high groups were 81.7% and 55%, respectively (log-rank p = 0.007).

We further dichotomised our patients based on the median age (65.3 years old) and did not find significant differences in survival (log-rank p = 0.22).

Finally, we can only disagree with Chong's conclusion stating that SUV does not provide additional clinically relevant information compare to pTNM staging alone as several contemporary studies on lung cancers have supported our conclusions [3,4]. In the Sloan-Memorial series [5], Downey et al. included all stage I to stage IV patients for statistical analysis and the subanalysis on early stage tumors was performed with a SUVmax cut-off (4.3) calculated from the entire cohort of patients which might have been misleading or brought different conclusions.

References

1. Chong CF. Re: Prognostic value of FDG uptake in early stage non-small cell lung cancer. Eur J Cardiothorac Surg 2008;34:932.[Free Full Text]
2. Hanin FX, Lonneux M, Cornet J, Noirhomme P, Coulon C, Distexhe J, Poncelet AJ. Prognostic value of FDG uptake in early stage non-small cell lung cancer. Eur J Cardiothorac Surg 2008;33(5):819-823.[Abstract/Free Full Text]
3. Goodgame B, Pillot GA, Yang Z, Shriki J, Meyers BF, Zoole J, Gao F, Dehdashti F, Patterson A, Siegel BA, Govindan R. Prognostic value of preoperative positron emission tomography in resected stage I non-small cell lung cancer. J Thorac Oncol 2008;3(2):130-134.[CrossRef][Medline]
4. de Jong WK, van der Heijden HF, Pruim J, Dalesio O, Oyen WJ, Groen HJ. Prognostic value of different metabolic measurements with fluorine-18 fluorodeoxyglucose positron emission tomography in resectable non-small cell lung cancer: a two-center study. J Thorac Oncol 2007;2(11):1007-1012.[CrossRef][Medline]
5. Downey RJ, Akhurst T, Gonen M, Park B, Rusch V. Fluorine-18 fluorodeoxyglucose positron emission tomographic maximal standardized uptake value predicts survival independent of clinical but not pathologic TNM staging of resected non-small cell lung cancer. J Thorac Cardiovasc Surg 2007;133(6):1419-1427.[Abstract/Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Alain J. Poncelet Permission Requests Google Scholar Articles by Poncelet, A. J. Articles by Hanin, F.-X. PubMed Articles by Poncelet, A. J. Articles by Hanin, F.-X. Related Collections Lung - cancer Lung - other Mediastinum Trachea and bronchi