Ⅲ期非小细胞肺癌放射治疗射野累及器官的放射损伤研究

Clinical study of irradiation-induced injury of organs at risk in radiotherapy of Stage Ⅲnon-small cell lung cancer

目的：探讨Ⅲ期非小细胞肺癌(nonsmall cell lung cancer，NSCLC)适形放射治疗中累及野照射组(involved—field irradiation，IFI组)提高靶区剂量的同时，放射损伤是否高于预防照射组(elective node irradiation，ENI组)。方法：将200例Ⅲ期NSCLC患者随机分为IFI组和ENI组，IFI组处方量为68～74Gy／34～37次，ENI组为60-64Gy／30-32次，比较两组的近期疗效和放射损伤。结果：IFI组和ENI组的CR率分别是35％和27％，其差异无统计学意义，X^2=1．50，P=0．23；但总有效(CR4-PR)率分别是90％和79％，其差异有统计学意义，X^2=4．62，P=0．03。IFI组骨髓抑制和心脏损伤低于ENI组，但差异无统计学意义，P值分别为0．14和0．52；IFI组和ENI组放射性食管炎发生率相同(1～2级和3级的P值分别为0.59和0．71)；IFI组和ENI组急性放射性肺炎发生率分别为17％和29％，差异有统计学意义，X^2=4．06，P=0．04。根据剂量体积直方图(dose-volume histogram，DVH)分析，全肺接受≥20Gy的体积(V20)与放射性肺炎发生率的关系如下：V20<20％者为10．8％(13／120)，V20为20％～25％者为32．1％(17／53)，V20为25％～30％者为52．3％(11／21)，V20≥30％者为83．3％(5／6)。结论：IFI治疗Ⅲ期NSCLC，患者耐受性好，总有效率高于ENI组，放射损伤发生率并未增加，放射性肺炎的发生率低于ENI组，即IFI提高靶区照射剂量的同时不增加放射损伤，有望提高患者的长期生存率。

OBJECTIVE:To explore the incidence of irradiation-induced injury while the involved-field irradiation (IFI) increased the target doses in stage Ⅲ non-small cell lung cancer (NSCLC). METHODS: From September 1997 to November 2001, 200 patients with stage-Ⅲ NSCLC were randomized into two groups-IFI and ENI (elective node irradiation). The IFI group were irradiated by 68-74 Gy/34-37 f. The ENI group were irradiated by 60-64 Gy/30-32 f. The short-time curative effect and the irradiation-induced injury were compared. RESULTS: The CR rates were 35% and 27% in IFI group and ENI group, respectively, and there was no significance, χ~2=1.50,P=0.23, while the overall response (CR+PR) rates were 90% and 79%, χ~2=4.62,P=0.03. Bone marrow depression and radiation-induced heart damage were lower in IFI group than in ENI group, but there were no significance, P values were 0.14 and 0.52. Radiation esophagitis incidence were the same in IFI and ENI groups (1-2 grade and 3 grade’s P value were 0.59 and 0.71). Radiation-induced pneumonitis occurred in 17% of patients in IFI and 29% in ENI, respectively. The difference were significant, χ~2=4.06,P=0.04. The relation between the lung volume receiving≥20 Gy(V_(20)) and the incidence of radiation-induced pneumonitis as the basis of Dose-volume Histogram(DVH)were as follows: while V_(20)<20%, the radiation-induced pneumonitis incidence was 10.8%(13/120); V_(20) ranged from 20% to 25%, it was 32.1%(17/53); V_(20) between 25% and 30%, 52.3%(11/21); V_(20)≥30%, 83.3%(5/6), respectively. CONCLUSIONS: IFI for the patients of Stage-Ⅲ NSCLC is well tolerated. The overall response rate is higher than in ENI. The incidence of irradiation-induced injury is not increased, while the radiation-induced pneumonitis is lower in IFI than in ENI. That is to say, IFI elevates the target doses but does not increase the irradiation-induced injury, thus would improve the survival.