This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Heist, R. S. Articles by Christiani, D. C. Search for Related Content PubMed Articles by Heist, R. S. Articles by Christiani, D. C. Related Articles Related Correspondence Social Bookmarking                            What's this?

In Reply

Massachusetts General Hospital, Boston, MA

David C. Christiani

Harvard School of Public Health, Boston, MA

We thank Patel et al for their interest in our article.¹ We agree with Patel et al that there are intriguing questions raised by our findings that should be investigated further.

We analyzed overall survival rather than disease-free survival (DFS). We agree that DFS would also be an important end point to study. However, in these patients who had been enrolled since 1992, there had been no predetermined schedule for follow-up of disease progression, and clinical outcomes were collected retrospectively. Therefore, the most stable end point was overall survival, rather than DFS. In our future studies, we are preparing the infrastructure to have a prospective, prespecified data collection regarding outcomes and progression. The ability to identify recurrences and outcomes on a prospective schedule will be a great asset to the current work.

In addition, we did not specifically look at vascular endothelial growth factor (VEGF) plasma levels in relation to polymorphism status in this study. However, in another study, we reported an association of VEGF plasma levels with the VEGF 936C>T polymorphisms, with lower plasma VEGF levels being associated with the variant T allele.² We are investigating plasma and tumor VEGF levels in ongoing studies.

Finally, Patel et al inquire about the P values in Table 4. The P value of .04 is for the log-rank test comparing survival curves among the four subgroups of 0, 1, 2, and 3 variant alleles. The CIs shown in Table 4 for the crude and adjusted hazard ratios are derived from Cox proportional hazard models, which compare the individual subgroups to the reference group of 0 variant alleles, with each subgroup fitted as an indicator variable. The P trend of .006 is reported to show the trend with these subgroups fitted as a continuous variable.

AUTHORS’ DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST

The author(s) indicated no potential conflicts of interest.

REFERENCES

1. Heist RS, Zhai R, Liu G, et al: VEGF polymorphisms and survival in early-stage non-small-cell lung cancer. J Clin Oncol 26:856-862, 2008[Abstract/Free Full Text]

2. Zhai R, Gong MN, Thompson TB, et al: Genotypes and haplotypes of VEGF gene are associated with higher ARDS mortality and lower VEGF plasma levels. Thorax 62:718-722, 2007[Abstract/Free Full Text]

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

Related Correspondence

• Vascular Endothelial Growth Factor Polymorphisms in Early-Stage Non–Small-Cell Lung Cancer
  Mehul Patel, Sikander Ailawadhi, Francisco Hernandez-Ilizaliturri, and Gregory E. Wilding
  JCO 2008 26: 3289-3290 [Full Text]

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Heist, R. S. Articles by Christiani, D. C. Search for Related Content PubMed Articles by Heist, R. S. Articles by Christiani, D. C. Related Articles Related Correspondence Social Bookmarking                            What's this?