乳腺癌根治术后三维调强放疗与三维适形放疗剂量学比较及不良反应观察

Dosimety comparison of IMRT and 3D-CRT for breast cancer after radical surgery and adverse reactions observation

目的比较乳腺癌根治术后调强放射治疗(IMRT)与适形放疗(3D-CRT)剂量学分布的优劣及不良反应,为临床乳腺癌根治术后选择放疗计划提供依据。方法选择100例接受乳腺癌根治术的乳腺癌病例,其中左侧乳腺癌患者53例,右侧乳腺癌患者47例;采用IMRT计划50例,采用3D-CRT计划50例,处方剂量均为50 Gy/25次。用剂量体积直方图(DVH)来比较IMRT和3D-CRT在计划靶区(PTV)及危及器官(OAR)的剂量学差异。结果 IMRT和3D-CRT放疗技术靶区剂量V95%的百分比分别为(97.8±1.3)%、(97.9±1.4)%,差异无统计学意义(P>0.05);IMRT的V105%、V110%、V115%与CRT相比明显偏低,差异有统计学意义(P<0.05);IMRT的均匀性指数(HI)为1.06±0.05,3D-CRT的HI为1.27±0.08,差异有统计学意义(P<0.05);IMRT的适形指数(CI)为0.88±0.04,3DCRT的CI为0.69±0.03,差异有统计学意义(P<0.05),表明IMRT的适形性较3D-CRT理想。患侧肺V20、V30、V40、V50分别降低了30.4%、38.6%、84.6%、87.5%,左侧患者心脏V30、V40、V50分别降低了70.8%、92.2%、100%,对侧乳腺平均剂量下降了40.1%,肝脏平均剂量下降了82.6%,均有显著性差异(P<0.05)。IMRT计划在放射性肺损伤、肝炎、心脏病、胸骨后疼痛、骨髓抑制、消化障碍等方面的不良反应发生率明显低于3D-CRT计划。结论乳腺癌根治术IMRT和3D-CRT都有较好的靶区覆盖率,但MIRT在提高靶区的适形度和剂量的均匀性均优于3D-CRT,并能降低OAR的受照剂量与容积,减少心脏、肺、肝等器官的不良反应的发生。

Objective To compare dosimetric distribution of intensity - modulated radiation therapy （IMRT） and three dimensional conformal radiotherapy （3 D - CRT） for breast cancer after radical surgery and adverse reactions, in order to provide the basis for breast cancer radio- therapy. Methods One hundred breast cancer patients were collected ; of them, 53 had cancer in the left breast and 47 had cancer in the right breast. The prescription dose for patients received IMRT （ n = 50） or 3D - CRT （ n = 50） was both 50 Gy/25 times. Dose - volume histogram （DVH） was used to compare dosimetry difference of3D -CRT and IMRT in planning target volume （PTV） and organs at risk （OAR）. Results PTV V95% of IMRT and 3 D - CRT were （97.8 ±1.3 ） % and （97.9 ± 1.4） % respectively, there was no statistically significant difference （ P 〉 0. 05 ） ; V105%, V110% , and V115% of IMRT were significantly lower compared with 3D -CRT, the difference was statistically significant （ P 〈 0.05 ）. Homogeneity index （HI） of IMRT was 1.06 ：1： 0.05, HI of 3D - CRT was 1.27 ± 0.08, the difference was statistically significant （ P 〈 0.05 ）. Conformal index （CI） of IMRT was 0.88 ± 0.04, CI of 3D - CRT was 0.69 ± 0.03 （ P 〈 0.05 ）, indicating that IMRT plan was more conformal than 3D - CRT. Ipsilateral lung V20, V30, V4o, and V5o were reduced by 30.4%, 38.6%, 84.6% and 87.5% respectively, cardiac V30, V40, and V50 were reduced by 70.8%, 92.2% and 100% respectively; the contralateral breast dose fell by an average of 40.1% （ P 〈 0.05 ）, mean dose of liver fell by 82.6% （ all P 〈 0.05 ）. Adverse reactions including radioactive lung injury, hepatitis, heart disease, retrostemal pain, bone marrow suppression and digestive disorders were significantly lower in IMRT plan. Conclusion Both IMRT and 3D - CRT have good target coverage, but MIRT is superior in HI and CI to 3D - CRT, and can reduce the absorbed dose and volume of OAR, and the incidence of adverse reactions in patients with breast cancer.