肺低剂量区体积预测急性放射性肺炎价值探讨

Low dose volume of the lung in prediction of acute radiation pneumonitis

目的 观察胸部肿瘤三维适形放疗患者放射性肺炎发生情况,分析其与各临床、剂量学因素关系,探讨低剂量区体积对放射性肺炎的预测价值.方法 2005-2008年本科收治的中晚期非小细胞肺癌（NSCLC）及食管癌患者共161例接受了三维适形放疗,其中局部晚期NSCLC患者53例,处方剂量60 Gy分30～34次,均行长春瑞滨＋顺铂同期化疗;食管癌患者108例,处方剂量58～70 Gy分29～35次,单纯放疗46例,余62例接受亚叶酸钙＋氟尿嘧啶＋顺铂同期化疗.对急性放射性肺炎进行Spearman等级相关分析、Logistic因素分析及受试者工作特征（ROC）曲线分析.结果 随访率100%.全组急性放射性肺炎总发生率为57.8%（93例）,其中NSCLC组为94%（50例,4、5级各1例）,食管癌组为39.8%（43例,无≥4级病例）.等级相关分析结果显示患者性别（r=0.19,P=0.016）、大体肿瘤体积（r=0.52,P=0.000））、平均肺剂量（r=0.33,P=0.000）、肺正常组织并发症概率（r=0.30,P=0.000）、接受5、10、15、20、25、30 Gy照射的肺体积百分比（肺V5～V30,r=0.21～0.29,P=0.000～0.027）均与放射性肺炎发生相关.Logistic因素分析结果显示肺V5（X2=7.07,P=0.008）、大体肿瘤体积（X2=10.21,P=0.001）是预测≥2级放射性肺炎最有价值指标.ROC曲线分析结果显示曲线下面积为0.684,P=0.000;曲线界值为V5=55%.肺V5≥55%组与〈55%组≥2级放射性肺炎发生率分别为43%（36/84）和18%（14/77）.结论 平均肺剂量、正常组织并发症概率、V5～V30可较好预测放射性肺炎的发生,其中V5可能是最有价值的预测性指标.当V5〉55%时≥2级的急性放射性肺炎的发生率可能会明显增加,制定治疗计划时除平均肺剂量、V20、V30外,还应将低剂量区体积限制在适当范围内.

Objective To observe the incidence of radiation pneumonitis （RP） in patients with non-small cell lung cancer （NSCLC） or esophageal carcinoma treated by three-dimensional conformal radiation therapy （3DCRT）, and investigate the predictive value of low dose volume of the lung on RP.Methods From Mar 2005 to Aug 2008, 161 patients with locally advanced NSCLC or esophageal carcinoma received 3DCRT. Fifty-three patients with NSCLC received radiotherapy of 60 Gy/30 -34 fx and concurrent chemotherapy of navelbine plus cisplatin （NP）. Among the 108 patients with esophageal carcinoma with prescription doses ranging from 58 Gy/29 fx to 70 Gy/35 fx, 46 and 62 received 3DCRT alone or 3DCRT with concurrent chemotherapy of calcium folinate, 5-Fu and cisplatin （LFP）, respectively. Univariate and multivariate analysis and receiver operating characteristics （ROC） curves were performed to assess the correlated factors of RP. Results The follow-up rate was 100%. The rate of RP was 57. 8% （93/161） for all patients, 94% （50/53,including 1 with Grade 4 and 1 with Grade 5） for patients with NSCLC, and 39.8% （43/108, none with Grade 4 and 5） for patients with esophageal carcinoma. The correlative factors included the sex, volume of gross tumor volume （GTV）, mean lung dose （MLD）, V5, V10, V15, V20, V25 and V30 of normal lung according to Spearman correlative analysis. Univariate analysis showed that all the 9 factors could predict RP. Only V5 and the volume of GTV were found independently associated with Grade 2 or more RP in multivariate analysis. ROC analysis indicated that the cut-off point of the curve was 55% with the area under ROC curve of 0. 684 （P = 0. 000）. For the patients with lung V5 ≥ 55% and 〈 55% ,43% （36/84） and 18% （14/77） developed RP of Grade 2 or more, respectively. Conclusions Dosimetric parameters including MLD, normal tissue complication probability, and V5-V30 could predict RP. V5 may be the most valuable predictor. When V5 exceeds 55%, the probability of RP of grade 2 or more may increase notably. Besides the limitation of MLD, V20 and V30, the volume of low dose region should be also limited to a lower range during treatment planning.