肿瘤靶体积对Ⅲ期非小细胞肺癌三维适形放疗长期疗效的影响

Effect on Long-time Survival for Different Tumor Volume in StageⅢNon-small Cell Lung Cancer after Three Dimensional Conformal Radiotherapy

目的分析肿瘤靶体积大小对Ⅲ期非小细胞肺癌（NSCLC）三维适形放疗（3D-CRT）长期疗效的影响。方法收集2000年8月-2004年12月行三维适形放疗的72例Ⅲ期NSCLC患者资料。其中，ⅢA期29例、ⅢB期43例。单纯放疗32例、放疗联合化疗40例；采用前程常规＋后程三维适形放疗者28例、全程三维适形放疗者44例；中位等效生物剂量6625cGy（范围5000-7800cGy）。采用剂量体积直方图（DVH）计算肿瘤靶体积（GTV）、临床靶体积（CTV）、计划靶体积（PTV）。放射性肺炎和放射性食管炎采用RTOG标准评价。结果随访5年，随访率95．8％。放疗后CR14例、PR42例、SD16例，1、3、5年总生存率及中位生存期分别为45．8％、15．3％、10．5％和10．2月。按照GTV中位值155cm^2分为两组，只有GTV〉155cm。组2级以上放射性肺炎发生率高（P〈0．05）；而性别、年龄、T、N、TNM、等效生物剂量、照射方式、化疗、近期疗效和放射性食管炎，两组间分别比较，差异无统计学意义（P〉0．05）。GTV≤155cm^2和〉155cm’放疗后1、3、5年生存率和中位生存期分别为61．1％、19．4％、16．2％、17月和30．6％、11．1％、4．2％、9月（X^2=5．16，P=0．023）。CTV和PTV按照中位值分两组，两组间生存率的比较差异均有统计学意义（P〈0．05）。全组预后单因素分析显示GTV、CTV、PTV、近期疗效（CR＋PR/SD）与预后生存有关（P〈0．05）：多因素分析显示GTV和近期疗效是独立预后因素。结论肿瘤靶体积大小是影响Ⅲ期非小细胞肺癌放疗预后的重要因素，近期疗效也影响预后生存。

Objective To explore the effects of tumor volume on long-time efficacy of stage Ⅲ non-small cell lung cancer （NSCLC） after three dimensional conformal radiotherapy （3D-CRT）. Methods From August 2000 to December 2004, 72 patients, 29 cases were in ⅢA and 43 cases in ⅢB stage. 32 cases were treated with radiotherapy alone, while 40 cases with concurrent or sequential radiotherapy and chemotherapy. 28 cases were treated with conventional radiotherapy （CRT） and later-course 3D-CRT, while 44 cases with 3D-CRT. The median equivalent dose was 6 625 cGy（5 000-7 800 cGy）. DVH was used for assessing GTV, CTV and PTV.Standard of RTOG Radiation was used for evaluating induced esophagitis and pneumonitis. Results 69 cases were followed up for 5 years and rate was 95.8%. After radiotherapy, there were 14 cases of CR, 42 cases of PR, and 16 cases of SD. Overall survival rate and median survival time of 1 year, 3 years, and 5 years was 45.8%, 15.3%, 10.5% and 10.2 months, respectively. All patients were divided into two groups according to GTV median （155 cm^3）. Only the incidence of 〉 grade 2 radiation induced pneumonitis in group of GTV 〉 155 cm3 was higher than that in group of GTV≤ 155 cm3 （P〈0.05）, while there was no significant difference in gender, age, T, N, TNM, biologic equipotent dose, radiation style, chemotherapy and radiation esophagitis between two groups. Overall survival rate and median survival time of 1 year, 3 years and 5 years of patients with GTV≤ 155 cm3 and 〉 155 cm3 were 61.1%, 19.4%, 16.2%, 17 months and 30.6%, 11.1%, 4.2%, 9 months respectively（X^2=5.16, P=0.023）. CTV and PTV were divided into two groups according to median, and there was significant difference in survival rate （P〈0.05）. With univariate analysis of all prognosis, GTV, CTV, PTV, and immediate effect were related with prognostic survival （P〈0.05）. Multivariable analysis indicated GTV and immediate effect were independent prognostic factors. Conclusion GTV was one important prognostic factor for stage III NSCLC after 3D-CRT, and immediate effect was another prognostic factor.