Review
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World J Radiol. Sep 28, 2014; 6(9): 708-715
Published online Sep 28, 2014. doi: 10.4329/wjr.v6.i9.708
Radiation pneumonitis after stereotactic radiation therapy for lung cancer
Hideomi Yamashita, Wataru Takahashi, Akihiro Haga, Keiichi Nakagawa
Hideomi Yamashita, Wataru Takahashi, Akihiro Haga, Keiichi Nakagawa, Department of Radiology, University of Tokyo Hospital, Tokyo 113-8655, Japan
Author contributions: Yamashita H designed the study and performed the majority of work, including literature review and writing the first draft of the manuscript; Takahashi W, Haga A and Nakagawa K provided advice regarding important intellectual content of the topical discussion.
Correspondence to: Hideomi Yamashita, MD, PhD, Department of Radiology, University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. yamachan07291973@yahoo.co.jp
Telephone: +81-3-58008667 Fax: +81-3-58008935
Received: December 7, 2013
Revised: July 1, 2014
Accepted: July 15, 2014
Published online: September 28, 2014
Abstract

Stereotactic body radiation therapy (SBRT) has a local control rate of 95% at 2 years for non-small cell lung cancer (NSCLC) and should improve the prognosis of inoperable patients, elderly patients, and patients with significant comorbidities who have early-stage NSCLC. The safety of SBRT is being confirmed in international, multi-institutional Phase II trials for peripheral lung cancer in both inoperable and operable patients, but reports so far have found that SBRT is a safe and effective treatment for early-stage NSCLC and early metastatic lung cancer. Radiation pneumonitis (RP) is one of the most common toxicities of SBRT. Although most post-treatment RP is Grade 1 or 2 and either asymptomatic or manageable, a few cases are severe, symptomatic, and there is a risk for mortality. The reported rates of symptomatic RP after SBRT range from 9% to 28%. Being able to predict the risk of RP after SBRT is extremely useful in treatment planning. A dose-effect relationship has been demonstrated, but suggested dose-volume factors like mean lung dose, lung V20, and/or lung V2.5 differed among the reports. We found that patients who present with an interstitial pneumonitis shadow on computed tomography scan and high levels of serum Krebs von den Lungen-6 and surfactant protein D have a high rate of severe radiation pneumonitis after SBRT. At our institution, lung cancer patients with these risk factors have not received SBRT since 2006, and our rate of severe RP after SBRT has decreased significantly since then.

Keywords: Radiation pneumonitis, Stereotactic radiation therapy, Dose-volume factors, Krebs von den Lungen-6, Surfactant protein D, Computed tomography changes

Core tip: Radiation pneumonitis (RP) is one of the most common toxicities after stereotactic body radiation therapy (SBRT). Although most RP is Grade 1 or 2 and either asymptomatic or manageable, a few cases are severe and there is a risk for mortality. A dose-effect relationship has been demonstrated that can be used for treatment planning. Other prognostic indicators of severe radiation pneumonitis after SBRT are an interstitial pneumonitis shadow on computed tomography scan and high levels of serum Krebs von den Lungen-6 and surfactant protein D before treatment.