Demirci Senem, Nam Jiho, Hubbs Jessica L, Nguyen Thu, Marks Lawrence B
Department of Radiation Oncology, Ege University School of Medicine, Izmir, Turkey.
Int J Radiat Oncol Biol Phys. 2009 Mar 15;73(4):980-7. doi: 10.1016/j.ijrobp.2008.11.016.
Cardiac toxicity after breast radiotherapy (RT) has been widely described in "older" RT trials (i.e., using larger fraction sizes, wide RT fields, and orthovoltage energy). The results from more "modern" RT trials have shown less cardiac toxicity. The comparisons between the "older" and "modern" trials are confounded by the longer follow-up time in the "older" trials. We systematically assessed the effect of treatment era and follow-up duration on the reported rates of cardiac toxicity associated with RT.
The published data were surveyed using PubMed to identify studies using "breast cancer," "irradiation/radiotherapy," "cardiac/heart," and "toxicity/morbidity/mortality" in a keyword search. Relevant data were extracted from the identified trials. The trials were defined as "older" (patient accrual start year before 1980) and "modern" (patient accrual start year in or after 1980) to segregate the trials and assess the treatment era effect. A 10-year follow-up duration was used as a cutoff to segregate and analyze trials with varying lengths of follow-up.
We analyzed 19 published reports of patients treated between 1968 and 2002 (5 randomized controlled trials, 5 single- or multi-institutional studies, and 9 national cancer registry database reviews). In the reviewed trials, all the older trials reported excess cardiac toxicity, typically with a median of >10-15 years of follow-up. However, the vast majority of modern RT trials had shorter median follow-up durations, typically <or=10 years and did not report an excess toxicity risk. The modern studies lacked longer follow-up.
Additional follow-up is needed to ensure that modern methods effectively reduce cardiac toxicity. Continued diligence to minimize cardiac exposure remains prudent.
在“早期”放疗试验（即使用较大分次剂量、宽放疗野和正交电压能量）中，已广泛描述了乳腺癌放疗（RT）后的心脏毒性。更多“现代”放疗试验的结果显示心脏毒性较低。“早期”和“现代”试验之间的比较因“早期”试验较长的随访时间而混淆。我们系统地评估了治疗时代和随访持续时间对报道的与放疗相关的心脏毒性发生率的影响。
使用PubMed对已发表的数据进行检索，以关键词搜索识别使用“乳腺癌”“照射/放疗”“心脏/心脏的”和“毒性/发病率/死亡率”的研究。从识别出的试验中提取相关数据。将试验定义为“早期”（患者入组开始年份在1980年之前）和“现代”（患者入组开始年份在1980年或之后），以区分试验并评估治疗时代的影响。以10年随访持续时间作为截止点，对随访时间长短不同的试验进行区分和分析。
我们分析了1968年至2002年间治疗患者的19篇已发表报告（5项随机对照试验、5项单机构或多机构研究以及9项国家癌症登记数据库综述）。在纳入综述的试验中，所有早期试验均报告了心脏毒性增加，通常中位随访时间>10 - 15年。然而，绝大多数现代放疗试验的中位随访时间较短，通常≤10年，且未报告毒性风险增加。现代研究缺乏更长时间的随访。
需要进一步随访以确保现代方法能有效降低心脏毒性。持续谨慎以尽量减少心脏照射仍是明智之举。
