手术方式对乳腺癌术后内乳淋巴引流区非计划性受照剂量的影响分析

Incidental radiation dose to internal mammary chain in breast cancer affected by surgery method

目的 评估乳腺癌术后放疗患者内乳淋巴引流区(IMC)非计划性照射剂量,明确乳腺癌手术方式对IMC非计划性受照剂量的影响。方法 回顾性分析2012-01-12-2017-01-26山东省肿瘤防治研究院210例保留乳房术(BCS)后及138例改良根治术(MRM)后接受乳腺(胸壁)±锁骨上淋巴引流区(SCF)放疗的患者,其中131例行患侧乳腺(胸壁)+SCF照射,217例仅行患侧乳腺(胸壁)照射,所有患者原治疗计划中均未接受IMC照射。依据肿瘤放射治疗协作组(RTOG)标准勾画患侧IMC,依据手术方式不同分为BCS及MRM组,比较2组患者间IMC非计划性受照剂量、第1~3肋间IMC受照剂量的差异性。结果 IMC非计划性受照剂量中位数为29.69 Gy, MRM组患者IMC及第1、2肋间IMC非计划性受照剂量高于BCS组(32.85 vs 27.10 Gy,Z=-3.327,P=0.001;26.60 vs 12.50 Gy,Z=-6.922,P<0.001;34.63 vs 30.42 Gy,Z=-2.777,P=0.005),而第3肋间2组差异无统计学意义(37.41 vs 36.24 Gy,Z=-1.103,P=0.270)。131例接受侧乳腺(胸壁)+SCF放疗患者IMC(32.87 vs 27.19 Gy)、第1(26.8 vs 13.09 Gy)和2(34.65 vs 30.46 Gy)肋间内乳区非计划性受照剂量高于单纯患侧乳腺(胸壁)放疗组。二分类logistic回归分析结果显示,手术方式及是否行SCF照射均与IMC非计划性受照剂量有关联(OR=1.034,95%CI:1.015~1.054,P=0.001;OR=1.034,95%CI:1.014~1.054,P=0.001)。结论 手术方式和SCF照射野的加入均会影响IMC非计划性受照剂量。相较于MRM患者,BCS患者IMC非计划性受照剂量更低,尤其是第1肋间。

Objective To analyze incidental irradiation doses to the internal mammary nodes chain(IMC) after modified radical mastectomy(MRM) and breast conserving surgery(BCS).Mthods Totally 210 patients who had undergone breast conserving surgery and 138 patients who had undergone modified radical mastectomy(MRM) received breast(chest wall) ± supraclavicular lymphatic drainage area(SCF) radiotherapy from January 12,2012 to January 26,2017 in Shandong Cancer Hospital and Institute.Among them,131patients received breast(chest wall)+ SCF irradiation on the affected side,and 217patients only received breast(chest wall)irradiation on the affected side.All patients did not receive IMC irradiation in the original treatment plan.The IMC of the affected side was contoured according to Radiation Therapy Oncology Group(RTOG)consensus.Patients were divided into BCS group and MRM group according to different surgical methods.IMC incidental exposure dose and difference of doses to IMC between 1st and 3rd intercostal spaces were compared.Results The median incidental radiation dose to IMC was 29.69Gy and the dose delivered to IMC,ICS1,ICS2showed a greater coverage in MRM group compared with BCS group(32.85 vs 27.10Gy,Z=-3.327,P=0.001;26.60 vs 12.50Gy,Z=-6.922,P<0.001;34.63 vs30.42Gy,Z=-2.777,P=0.005).The dose delivered to ICS3showed no difference between MRM and BCS(37.41 vs 36.24Gy,Z=-1.103,P=0.270).Totally 131patients received radiotherapy to the chest wall and ipsilateral supraclavicular fossa(SCF).The Dmean for IMC(32.87 vs 27.19Gy),ICS1(26.8 vs 13.09Gy),ICS2(34.65 vs 30.46Gy)were all greater in chest wall+ SCF radiotherapy group than chest wall(whole breast)radiotherapy group.The results of binary logistic regression analysis showed that both the surgery and SCF irradiation were the parameters affecting the incidental radiation Dmean of the IMC[HR=1.034(95%CI:1.015-1.054),P=0.001;HR=1.034(95%CI:1.014-1.054),P=0.001].Conclusions Both the surgery and SCF irradiation are the affecting factors of IMC incidental dose.Patients underwent BCS are accepted significantly lesser incidental radiation to IMC than those receiving MRM,especially for ICS1.