编者按：乳腺癌放疗对心脏的辐射可以引起心脏损伤，尤其对于泵出动脉血的左心室，但是由于心脏不大，此前尚无研究深入分析乳腺癌放疗对心脏不同部位的影响。
2018年5月23日，美国临床肿瘤学会《临床肿瘤学杂志》在线发表英国牛津大学、丹麦乳腺癌协作组、哥本哈根大学王国医院、北丹麦地区医院、南丹麦大学欧登塞医院、美国伊利诺伊州诺默尔社区癌症中心、瑞典卡罗林学院、丹德吕德医院、斯德哥尔摩南部综合医院的患者个别数据横断面研究报告，以解剖麻雀的精神，深入分析了乳腺癌放疗后不同辐射剂量对心脏内部不同结构的损伤。
该研究获取了1958～2001年458例女性接受乳腺癌放疗后发生冠状动脉重大事件的放疗方案和心脏损伤部位信息。其中，414例女性记录了左心室损伤部位、左心室5个部位的放疗剂量；133例女性记录了狭窄≥70%的冠状动脉病变部位、冠状动脉6个部位的放疗剂量。对于各个部位，比较左侧和右侧乳腺癌女性的数量。
结果发现，左心室损伤女性414例，其中左侧乳腺癌243例、右侧乳腺癌171例（左右比值：1.42，95%置信区间：1.17～1.73）；左侧与右侧的乳腺癌放疗相比，左心室放射剂量较大（平均剂量：8.3 Gy比0.6 Gy，相差7.7 Gy）。
左侧与右侧的乳腺癌放疗相比，左心室不同部位损伤女性比例如下：
下壁：0.94（95%：0.70～1.25）
侧壁：1.42（95%：1.04～1.95）
间隔：2.09（95%：1.37～3.19）
前壁：1.85（95%：1.39～2.46）
心尖：4.64（95%：2.42～8.90）
左心室上述部位的左侧与右侧乳腺癌放疗剂量相差2.7、4.9、7.2、10.4、21.6 Gy（趋势分析双侧P<0.001）。
左侧与右侧的乳腺癌放疗相比，冠状动脉不同部位病变女性比例如下：
右近端：0.48（0.26～0.91）
右中远端：1.69（0.85～3.36）
左回旋支近端：1.46（0.72～2.96）
左回旋支远端：1.11（0.45～2.73）
左前降支近端：1.89（1.07～3.34）
左前降支中远端：2.33（1.19～4.59）
冠状动脉上述部位的左侧与右侧乳腺癌放疗剂量相差-5.0、-2.5、1.6、3.5、9.5、38.8 Gy（趋势分析双侧P=0.002）。
因此，对于左心室和冠状动脉的不同部位，较大的辐射剂量与较多的损伤密切相关，表明所有部位对辐射敏感，应该将所有部位的剂量减少至最小。
J Clin Oncol. 2018 May 23. [Epub ahead of print]
Cardiac Structure Injury After Radiotherapy for Breast Cancer: Cross-Sectional Study With Individual Patient Data.
Carolyn Taylor, Paul McGale, Dorthe Bronnum, Candace Correa, David Cutter, Frances K. Duane, Bruna Gigante, Maj-Britt Jensen, Ebbe Lorenzen, Kazem Rahimi, Zhe Wang, Sarah C. Darby, Per Hall, Marianne Ewertz.
Nuffield Department of Population Health, University of Oxford; George Institute for Global Health, University of Oxford, Oxford, United Kingdom; North Denmark Regional Hospital, Hjoerring; Danish Breast Cancer Cooperative Group, Rigshospitalet, Copenhagen; Odense University Hospital, Odense, Denmark; Community Cancer Center, Normal, IL; Karolinska Institutet; Danderyd Hospital; South General Hospital, Stockholm, Sweden.
PURPOSE: Incidental cardiac irradiation can cause cardiac injury, but little is known about the effect of radiation on specific cardiac segments.
METHODS: For 456 women who received breast cancer radiotherapy between 1958 and 2001 and then later experienced a major coronary event, information was obtained on the radiotherapy regimen they received and on the location of their cardiac injury. For 414 women, all with documented location of left ventricular (LV) injury, doses to five LV segments were estimated. For 133 women, all with documented location of coronary artery disease with ≥ 70% stenosis, doses to six coronary artery segments were estimated. For each segment, numbers of women with left-sided and right-sided breast cancer were compared.
RESULTS: Of women with LV injury, 243 had left-sided breast cancer and 171 had right-sided breast cancer (ratio of left v right, 1.42; 95% CI, 1.17 to 1.73), reflecting the higher typical LV radiation doses in left-sided cancer (average dose left-sided, 8.3 Gy; average dose right-sided, 0.6 Gy; left minus right dose difference, 7.7 Gy). For individual LV segments, the ratios of women with left- versus right-sided radiotherapy were as follows: inferior, 0.94 (95% CI, 0.70 to 1.25); lateral, 1.42 (95% CI, 1.04 to 1.95); septal, 2.09 (95% CI, 1.37 to 3.19); anterior, 1.85 (95% CI, 1.39 to 2.46); and apex, 4.64 (95% CI, 2.42 to 8.90); corresponding left-minus-right dose differences for these segments were 2.7, 4.9, 7.2, 10.4, and 21.6 Gy, respectively (P trend < .001). For women with coronary artery disease, the ratios of women with left- versus right-radiotherapy for individual coronary artery segments were as follows: right coronary artery proximal, 0.48 (95% CI, 0.26 to 0.91); right coronary artery mid or distal, 1.69 (95% CI, 0.85 to 3.36); circumflex proximal, 1.46 (95% CI, 0.72 to 2.96); circumflex distal, 1.11 (95% CI, 0.45 to 2.73); left anterior descending proximal, 1.89 (95% CI, 1.07 to 3.34); and left anterior descending mid or distal, 2.33 (95% CI, 1.19 to 4.59); corresponding left-minus-right dose differences for these segements were -5.0, -2.5, 1.6, 3.5, 9.5, and 38.8 Gy (P trend = .002).
CONCLUSION: For individual LV and coronary artery segments, higher radiation doses were strongly associated with more frequent injury, suggesting that all segments are sensitive to radiation and that doses to all segments should be minimized.
DOI: 10.1200/JCO.2017.77.6351
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