Lohr Frank, Heggemann Felix, Papavassiliu Theano, El-Haddad Mostafa, Tomé Oliver, Dinter Dietmar, Dobler Barbara, Kraus-Tiefenbacher Uta, Borggrefe Martin, Wenz Frederik
Klinik für Strahlentherapie und Radioonkologie, Universitätsklinikum Mannheim, Germany.
Strahlenther Onkol. 2009 Apr;185(4):222-30. doi: 10.1007/s00066-009-1892-0. Epub 2009 Apr 16.
Postoperative radiotherapy after breast cancer surgery effectively reduces local relapses. A survival benefit after breast conservation, however, has only been proven recently which was in part due to excessive cardiac mortality of patients who had been treated with radiotherapy in the past.
The literature on postoperative radiotherapy for breast cancer was reviewed with regard to cardiac toxicity as the basis for hypothesis generation.
From numerous publications on cardiac toxicity of breast cancer radiotherapy, the following pattern emerges: in series where a high radiation dose was applied to a significant percentage of the heart (postmastectomy and postlumpectomy series) cardiac toxicity/mortality was increased versus a nonexposed cohort or for left over right disease. If, however, a relevant exposure of cardiac muscle could be more or less excluded based on the technique used (mainly more recent postlumpectomy radiotherapy), no cardiac toxicity was observed. Series for which individual dose exposure varied or could not be clarified also came to varying conclusions. Also due to retrospectively unclear dose distributions, an exact quantification of tolerance doses/effects of different geographic dose distribution patterns could not be performed to date. A particularly difficult question to answer is the threshold volume for clinically relevant cardiotoxicity with tangential radiotherapy at prescription doses. As a consequence, this precludes an estimate in which situations multifield intensity-modulated radiotherapy (IMRT) with its characteristic dose distribution pattern of a larger volume exposed to intermediate doses and higher mean/median heart doses (as shown in Figure 1) might be preferable.
This review updates the database on cardiac toxicity of breast cancer radiotherapy with special emphasis regarding the issues related to the clinical use of IMRT. Multifield IMRT may reduce the cardiac risk for a small subset of patients at excessive risk with conventional tangential radiotherapy due to unfavorable thoracic geometry, for whom partial-breast radiotherapy is not an option. Due to further concern about the effects of intermediate doses to larger heart volumes, potentially increased contralateral cancer risk and the long latency of clinically apparent toxicity, the introduction of breast IMRT should be closely followed. Accompanying functional studies may have the potential to detect cardiac toxicity at an earlier time.
乳腺癌手术后进行术后放疗可有效降低局部复发率。然而，保乳术后的生存获益直到最近才得到证实，部分原因是过去接受放疗的患者心脏死亡率过高。
以心脏毒性为假设生成的基础，对乳腺癌术后放疗的文献进行了综述。
从众多关于乳腺癌放疗心脏毒性的出版物中，出现了以下模式：在对相当比例的心脏施加高辐射剂量的系列研究中（乳房切除术后和乳房肿瘤切除术后系列），与未暴露队列或左乳对右乳疾病相比，心脏毒性/死亡率增加。然而，如果根据所使用的技术（主要是最近的乳房肿瘤切除术后放疗）或多或少可以排除心肌的相关暴露，则未观察到心脏毒性。个体剂量暴露不同或无法明确的系列研究也得出了不同的结论。此外，由于回顾性剂量分布不明确，迄今为止无法对不同地理剂量分布模式的耐受剂量/效应进行精确量化。一个特别难以回答的问题是，在处方剂量下进行切线放疗时，临床相关心脏毒性的阈值体积是多少。因此，这使得无法估计在哪些情况下，具有较大体积暴露于中等剂量和较高平均/中位心脏剂量特征剂量分布模式的多野调强放疗（IMRT）可能更可取（如图1所示）。
本综述更新了乳腺癌放疗心脏毒性的数据库，特别强调了与IMRT临床应用相关的问题。对于因胸部几何形状不利而常规切线放疗风险过高且无法选择部分乳腺放疗的一小部分患者，多野IMRT可能会降低心脏风险。由于对较大心脏体积的中等剂量效应、潜在增加的对侧癌症风险以及临床明显毒性的长潜伏期的进一步关注，应密切关注乳房IMRT的引入。伴随的功能研究可能有潜力更早地检测到心脏毒性。
