The Clinical Study Of Prediction For Radiation Pneumonia

Objective To prospectively study the relation between transforminggrowth factor beta-1(TGF-β₁), V₂₀, lung function(PFTs) and radiationpneumonia(RP).Methods From Jan 2004 to Dec 2005, 121 valid patients withoesophagus tumor or lung cancer were treated with routine thoraxradiotherapy(RT). Serum TGF-β1 was detected by enzyme linkedimmunosorbent assay(ELISA) and PFTs was measured by lung functionapparatus, including FVC, FEV1, Kco, Vcap and DM both before RT and afterRT as well as on day 20th aider RT beginning. All took chest CT scanningbefore RT, then DVH and V20 were gained through 3-dimensional TPS. Thepatients were radiated with 15 MV X-ray, DT60～68Gy, 30～34fractions,within 42～46days. RP was diagnosed based on contrasted CT combined withclinical symptoms. The degree of RP was defined according to the criteria ofRTOG and EORTC. All cases were followed up every 3 months.The data wasanalysed by Logistic regression model or chi-square test with statistical softSPSS version 10.0.Results RP occurred in 32 cases among all 121 patients. Of patientswith TGF-β₁ ratio(after RT/before RT)≧1 had more chances to have RP thanthose TGF-β₁ ratio＜1(p=0.000). To patients with V₂₀≧30%, the cases whoseTGF-β₁ ratio(after RT/before RT) were more than or equal to 1 had morechance to have RP than those TGF-β₁ ratio were less than 1(p=0.000).Moreovere, RP were found more frequently in patients with poor FEV₁ than in patients with normal FEV₁, though they both had high TGF-β₁ ratio. Theresults of Logistic Regression statistic showed that V₂₀ and TGF-β₁ ratio(alterRT/before RT) would influence the incidence of RP significantly. Patientswith V₂₀≧30% would have RP more easier than patients with V₂₀＜30%(OR=8.504). And the cases with TGF-β₁ ratio≧1 would also have morechances to show RP than others(OR=18.932). Patients with poor PFTs had notgained RP more frequently than ones with normal PFTs (p=0.079). Based onthe data of the study, a predictive equation could be founded, viz.PI=2.941×TGF-β₁ ratio+2.141×V₂₀-FEV₁/FVC.With 121 cases, the mediumvalue of PI is 2.89(1.7～6.8) and all patients could be divided into 3 groups,which are better prognosis group(55 cases, PI＜2.8), medium prognosisgroup(37 cases, 2.8≦PI＜4.5) and worse prognosis group(29 cases,PI≧4.5).Conclusion It may be concluded from the data above that theappropriate use of biological factor, TGF-β₁ combined with radiophysicselement, V₂₀ could predict radiation pneumonia. The equation of PI couldascertain patients with high risk of RP, so it could forecast the probability anddegree of RP for a radiotherapeutic plan.