Radiation pneumonitis after stereotactic radiation therapy for lung cancer

Stereotactic body radiation therapy(SBRT)has a locacontrol rate of 95%at 2 years for non-small cell lungcancer(NSCLC)and should improve the prognosis oinoperable patients,elderly patients,and patients withsignificant comorbidities who have early-stage NSCLCThe safety of SBRT is being confirmed in internationalmulti-institutional PhaseⅡtrials for peripheral lungcancer in both inoperable and operable patients,bureports 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 oneof the most common toxicities of SBRT.Although mospost-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 reportedrates of symptomatic RP after SBRT range from 9%to28%.Being able to predict the risk of RP after SBRT isextremely useful in treatment planning.A dose-effecrelationship has been demonstrated,but suggesteddose-volume factors like mean lung dose,lung V20and/or lung V2.5 differed among the reports.We foundthat patients who present with an interstitial pneumo-nitis 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 pneumo-nitis 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 de-creased significantly since then.