Related Experiment Video
Updated: Aug 9, 2026

Voluntary Breath-hold Technique for Reducing Heart Dose in Left Breast Radiotherapy
Published on: July 3, 2014
Simultaneous measurements of KL-6 and SP-D in patients undergoing thoracic radiotherapy
Yosuke Matsuno1, Hiroaki Satoh, Hiroichi Ishikawa
1Division of Respiratory Medicine, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan. c0430518@md.tsukuba.ac.jp
Purpose:
Radiation pneumonitis (RP) is a serious complication in patients undergoing thoracic radiotherapy (TRT). Serum KL-6 and SP-D have been shown to increase in several kinds of interstitial pneumonia. To evaluate their clinical usefulness in detecting RP, we serially measured them in patients receiving TRT.
Materials And Methods:
Thirty-nine patients, who received TRT for lung cancer between July 1999 and April 2004, were prospectively studied. Serum levels of KL-6 and SP-D were measured using enzyme-linked immunosorbent assays. Patients were followed up until August 2004 or their deaths.
Results:
During the period, RP occurred in 19 patients. In five patients with diffuse RP extended outside the radiation field, serum KL-6 levels increased, reaching more than 1,000 U/mL. Serum KL-6 levels at 40 Gy in patients who developed RP were higher than those without it (p = 0.0363, Mann-Whitney U test). In addition, serum KL-6 levels at 40 Gy in patients who developed RP were higher than those of pretreatment (p = 0.0126, Wilcoxon signed rank test). On the other hand, there were no statistical differences between sp-d at 40 Gy and those before TRT (P = 0.1165).
Conclusions:
Increased KL-6 at 40 Gy compared with those before treatment in patients undergoing TRT may be of clinical significance. KL-6 proved to be a useful indicator for estimating RP, while usefulness of SP-D was not confirmed in this study.

