乳腺癌保乳术后全乳加瘤床补量照射不同治疗计划的比较

目的 探讨乳腺癌保乳术后全乳加瘤床照射不同治疗计划靶区剂量适形度、靶区剂量分布均匀性及肺脏、心脏和对侧乳腺受照剂量体积的差异。方法 选择术腔各边界放置银夹且无腋窝淋巴结转移的12 例左侧乳腺癌保乳术后患者, 每例患者分别制定常规放疗(CRT)、无挡肺子野调强放疗(IMRT-F)、挡肺子野调强(IMRT-F-L) 和瘤床同步整合补量调强放疗(SIB-IMRT) 计划。比较不同治疗计划全乳靶区和瘤床靶区的剂量适形度和剂量分布均匀性, 对比不同治疗计划肺脏、心脏和对侧乳腺受照剂量体积。结果 各计划中V_{处方剂量- PTV}1 V_PTV1、V_PTV1 处方剂量 V_PTV2、V_{处方剂量-PTV2 V- 处方剂量、VPTV2-处方剂量 VPTV2组间差异均有统计学意义;CRT 计划中患侧肺V20显著高于不同方式的IMRT 计划, 但不同方式的IMRT 计划之间V20差异无统计学意义;CRT 计划中心脏受照剂量显著高于IMRT 和SIB-I MRT 计划。CRT 计划中对侧乳腺最大照射剂量 Dmax和平均剂量Dmean明显高于不同实现方式的IMRT计划, 但不同实现方式的IMRT 计划中 Dmax和Dmean差异无统计学意义。结论 IMRT-F、IMRT-F-L、SIB-I MRT 计划均显著优于 CRT 计划, 而不同方式I MRT 计划间除个别参数外差异无统计学意义。}

Comparison of different treat ment plannings for whole breast irradiation with tumor bed boost after breast-conservative surgery

Objective To explore the difference of conformity and homogeneity of dose distribution in the whole breast and tumor bedtargets and dose-volume parameters of the irradiated heart, lung and contralateral breast between the different treatment plannings for whole breast irradiation with tumor bed boost after breast-conservative surgery. Methods Twelve left-side breast cancer patients received breast-conservative surgery with negative axillary lymph node and with silver slips set inthe cavity were selected. The different plannings including conventional radiotherapy (CRT), forward intensity-modulated radiotherapy with no lung block segments (IMRT-F), forward intensity-modulated radiotherapy with lung block segments (I MRT-F-L) and si multaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) were completedfor each patient. The difference of conformity and homogeneity of dose distributioninthe whole breast andtumor bed targets, the relatedirradiated dose-volume parameters of the ipsilateral lung, heart and contralateral breast were compared among the different plannings.Results There were statistical differences of the ratios of breast volume contained by the prescribed dose given to PTV1(V_dose-PTV1)to V_PTV1, volume of PTV1 contained by the prescribed dose givento PTV1(V _PTV1-dose) to V_PTV2, conformal index of PTV1(CI_PTV1) and conformal index of PTV2(CI_PTV2) among the different plannings. The volume of the lung which received more than 20 Gy(V₂₀) in CRT planning was statistically higher those that in three I MRT plannings, but there was no significant difference among three types of IMRT. The dose irradiatedto the heart in the CRT planning was significantly higher thanthat in IMRT-F, IMRT-F-L and SIB-I MRT planning. D_max and D_mean in the contralateral breast for CRT plan were significantly higher than those inthree types of I MRT plannings, but with no significant difference of D_max and D_mean among three types of I MRT plannings. Conclusions Comparing the different types of treatment plannings for whole breast irradiation with tumor bed boost for the patients with left breast cancer after breast-conservative surgery, I MRT-F, I MRT-F-L and SIB-IMRT plannings are all statistically superior to CRT planning, but there are no statistical differences among three types of I MRT plannings except some other parameters.