乳腺癌锁骨上区不同放疗技术甲状腺剂量学比较及其对生存期和淋巴细胞亚群的影响

目的:比较乳腺癌锁骨上区不同放疗技术甲状腺剂量学特点,并对比其对患者生存期和淋巴细胞亚群的影响。方法:71例乳腺癌患者按照根治术后放疗方案分组,接受调强放疗(IMRT)者纳入IMRT组(n=37),接受三维适形放疗(3D-CRT)者纳入3D-CRT组(n=34)。比较两组患者计划靶区(PTV)剂量、甲状腺受量,放疗前后淋巴细胞亚群变化,以及5年无病生存率、总生存率,比较两种放疗技术甲状腺保护作用及其对患者预后的影响。结果:IMRT组Dmean、CI高于3D-CRT组,Dmax、HI低于3D-CRT组,差异有统计学意义(P<0.05)。IMRT组甲状腺剂量体积V20、V30、V40高于3D-CRT组,Dmin、Dmean也高于3D-CRT组,差异有统计学意义(P<0.05)。两组放疗后1 d淋巴细胞总数、B淋巴细胞百分比均较放疗前下降,CD3+、CD4+均较放疗前升高,3D-CRT组放疗后1 d淋巴细胞总数、B淋巴细胞百分比、CD3+、CD4+均高于IMRT组,差异有统计学意义(P<0.05)。IMRT组失访3例、3D-CRT组失访1例,其余患者均获得有效随访,随访时间≥5年。IMRT组5年无病生存率、总生存率分别为47.06%(16/34)、73.53%(25/34),与3D-CRT组的51.52%(17/33)、78.79%(26/33)比较,差异无统计学意义(P>0.05)。结论:IMRT的靶区剂量均匀性更佳,但甲状腺受量更高且患者放疗后淋巴细胞亚群变化更为明显;IMRT与3D-CRT对乳腺癌患者远期生存的影响无明显差异。

Thyroid dosimetric comparison of different techniques for supraclavicular radiotherapy of breast cancer and their effects on survival time and lymphocyte subsets

Objective To compare the thyroid dosimetric characteristics of different supraclavicular radiotherapy techniques for breast cancer,and to compare their effects on survival time and lymphocyte subsets.Methods According to the radiotherapy plan after radical mastectomy,71 patients with breast cancer were divided into intensity-modulated radiotherapy(IMRT)group(n=37)and three-dimensional conformal radiotherapy(3D-CRT)group(n=34).The dose of planning target volume(PTV),thyroid dose,changes of lymphocyte subsets before and after radiotherapy,5-year disease-free survival rate and overall survival rate were compared between two groups.Moreover,the thyroid-sparing effect of two radiotherapy technologies and their effects on the prognosis of patients were also compared.Results Compared with those in 3D-CRT group,the Dmean and CI of PTV in IMRT group were higher,while the Dmax and HI of PTV were lower,with statistical differences(P<0.05).Some dosimetric parameters(V20,V30,V40,Dmin and Dmean)of the thyroid in IMRT group were higher than those in 3D-CRT group,with statistical differences(P<0.05).After radiotherapy,the total number of lymphocytes and the percentage of B lymphocytes in the two groups were decreased,while CD3+and CD4+were increased.The total number of lymphocytes,the percentage of B lymphocytes,CD3+and CD4+in 3D-CRT group were higher than those in IMRT group on 1 day after radiotherapy,and the differences were statistically significant(P<0.05).Three cases were lost in IMRT group and 1 case in 3D-CRT group.The other patients were followed-up for more than 5 years.The differences between IMRT group and 3D-CRT group in 5-year disease-free survival rate47.06%(16/34)vs 51.52%(17/33)]and overall survival rate73.53%(25/34)vs 78.79%(26/33)]were trivial,without statistical difference(P>0.05).Conclusion IMRT has better target dose uniformity,but leads to higher thyroid dose and more obvious changes of lymphocyte subsets after radiotherapy.There is no significant difference between IMRT and 3D-CRT in the long-term survival of breast cancer patients.