非小细胞肺癌术后适形放疗肺损伤相关因素研究

目的 分析非小细胞肺癌(NSCLC)术后接受三维适形放疗(3DCRT)肺损伤的相关因素.方法 对2002年11月至2006年3月符合入组条件的90例患者进行回顾性分析,其中Ⅰ～Ⅱ期12例(切缘阳性),ⅢA期53例,ⅢB期25例.术后均接受了中位剂量60 Gy的3DCRT,38例接受了中位3周期术后化疗.观察指标为CTC 3.0 2级以上放射性肺炎(RP).应用ROC曲线分析健侧、患侧和双肺接受x Gy剂量的相对体积(Vx)和绝对体积与RP的关系.结果 全组共9例患者出现有症状的RP,RP发生率为10%.接受全肺切除的20例患者中无RP发生.RP中位发生时间在放疗开始后101 d,其中2级7例,3级2例.双肺V30、V35在RP组明显高于未发生RP组(19%∶14%,U=-2.16,P=0.030;15%:11%,U=-2.65,P=0.007).以患侧肺接受30 Gy照射的绝对体积作为分界点进行ROC曲线分析结果 显示曲线下面积为0.757,对RP预测的敏感性为88%、特异性为70%.患肺接受30 Gy照射的绝对体积>340 cm3的RP发生率明显高于体积<340 cm3的(29%∶3%,x2=9.75,P=0.003).结论 对于肺叶切除的NSCLC患者接受术后放疗,患肺接受30 Gy照射的绝对体积与RP相关.对全肺切除患者,单肺V20限制在10%以下,接受术后放疗是安全可行的.

Risk factors for radiation pneumonitis in patients with non-small-cell lung cancer treated with postoperative three-dimensional conformal radiotherapy

Objective To evaluate the relation between lung dosimetric parameters and the risk of symptomatic radiation pneumonitis (RP) in patients with non-small cell lung cancer (NSCLC) who had re-ceived postoperative radiotherapy. Methods From November 2002 to March 2006, 90 patients with NSCLC who had received postoperative 3-dimentinal conformal radiotherapy (3DCRT) were retrospectively analyzed, including 53 with stage ⅢA disease, 25 with stafe ⅢB disease and 12 with stage Ⅰ-Ⅱ disease but positive margins. Seventy (78%) patients underwent lobectomy, 20 ( 22% ) underwent pneumonectomy, and 38 ( 46% ) received adjuvant chemotherapy. The median radiation dose was 60 Gy given in 30 fractions of 2 Gy using 6 MV X-ray. The percentage of the whole lung volume ( Vx ) and the ipsilateral absolute lung volume ( Vipsi-dosewhich received more than a certain dose were calculated. The endpoint was grade 2 and above RP based on CTC AE 3.0. The relation between the dosimetric factors and RP was also analyzed with receiver operating characteristic (ROC) curves. Results Nine patients ( 10% ) developed symptomatic RP ( grade 2 in 7 and grade 3 in 2), and all of them were in the lobectomy group. No RP was observed in patients who received pneumonectomy. Both V30 and V35 were higher in patients with RP than those without ( 19% vs 14% ,U= -2.16,P=0.030, and 15% vs 11%,U= -2.65,P =0.007, respectively). The area under curve in receiver operating characteristic curves based on the relation between incidence of RP and the value of Vipsi-dose was 0. 757. Using Vipsi-30 of 340 cm3 as a cut-off to predict RP, the sensitivity and specificity were 88% and 70%, respectively. The incidence of RP was 3% in patients with Vipsi-30< 340 cm3 compared with 29% in those with Vipsi-30>340cm3 ( X2 = 9.75 , P = 0.003 ) . Conclusions More than340 cm3 of the ipsilateral lung receiving 30 Gy is significantly related to the risk of RP in patients undergoing lobectomy. It is safe for patients who undergo pneumonectomy to receive postoperative 3DCRT if lung V20 is less than 10%.