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BioMed Research International
Volume 2013 (2013), Article ID 731346, 11 pages
http://dx.doi.org/10.1155/2013/731346
Research Article

Immune Responses following Stereotactic Body Radiotherapy for Stage I Primary Lung Cancer

1Department of Radiation Oncology, Kofu Municipal Hospital, 366 Masutsubo, Kofu, Yamanashi 4000832, Japan
2Department of Radiation Oncology and Radiology, University of Yamanashi, School of Medicine, 1110 Shimokato, Chu-o, Yamanashi 4093898, Japan

Received 30 April 2013; Revised 15 September 2013; Accepted 20 September 2013

Academic Editor: Ruxana T. Sadikot

Copyright © 2013 Yoshiyasu Maehata et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. Immune responses following stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer (NSCLC) were examined from the point of view of lymphocyte subset counts and natural killer cell activity (NKA). Patients and Methods. Peripheral blood samples were collected from 62 patients at 4 time points between pretreatment and 4 weeks post-treatment for analysis of the change of total lymphocyte counts (TLC) and lymphocyte subset counts of CD3+, CD4+, CD8+, CD19+, CD56+, and NKA. In addition, the changes of lymphocyte subset counts were compared between patients with or without relapse. Further, the correlations between SBRT-related parameters and immune response were analyzed for the purpose of revealing the mechanisms of the immune response. Results. All lymphocyte subset counts and NKA at post-treatment and 1 week post-treatment were significantly lower than pre-treatment ( ). No significant differences in the changes of lymphocyte subset counts were observed among patients with or without relapse. The volume of the vertebral body receiving radiation doses of 3 Gy or more (VV3) significantly correlated with the changes of nearly all lymphocyte subset counts. Conclusions. SBRT for stage I NSCLC induced significant immune suppression, and the decrease of lymphocyte subset counts may be associated with exposure of the vertebral bone marrow.