August 17, 2006 -- 一个新研究显示，早期乳癌妇女接受对左胸放射线治疗后20年，比那些对右侧放射线治疗者更可能会发生心脏疾病。
Moffitt
癌症中心暨研究院的Eleanor E. R. Harris医师和她的团队在Pennsylvania大学报告他们的研究发现，研究同时也刊登在8月14日
临床肿瘤期刊线上版。
在伴随而来的评论中，Harvard 医学院的Abram Recht医师表示，Harris医师和她的同事的这篇文章是非常重要的，带来了相当大量的同性质治疗病患的长期资料，以及有关
冠心病的共同存在风险因子，且从回顾个体之医疗纪录而搜集相关事件。
【
高血压增加放射线导致之心脏疾病的风险】
Harris医师向Medscape表示，她的研究检视美国从1970年代末期迄今用在早期乳癌的放射线技术之使用，设计目的在尽量减小放射线对心脏的曝露，一个先前对此主题之研究包括了旧式的放射线技术。
他们设定观察1977年到1994年间、961位高冠状动脉疾病(CAD)比率之病患，比较在对左胸放射线治疗和对右侧放射线治疗后因心脏事件死亡的案例，以及原本就有的任何心脏风险因子是否增加了左胸放射线治疗之CAD风险增加。
治疗后的第20年，左胸放射线治疗者有较高的心脏事件死亡比率，累积风险率是6.4%，而右侧放射线治疗者则是3.6%；左胸放射线治疗者也有显著较高的胸痛比率、CAD、心肌梗塞(MI) (P < .002)；至于原本就有的任何心脏风险因子，只有高血压对左胸放射线治疗者有较高的CAD风险。
【并未纳入Anthracyclines和Trastuzumab】
不过，本研究之限制在于，病患并未如一般接受现今对许多乳癌病患来说是标准治疗的anthracyclines，也没接受用在约30%病患的trastuzumab (Herceptin, Genentech)，这两种药物处方也会导致心脏毒性，尽管Harris医师强调这3种治疗模式的机转是完全不同的。
放射线影响了冠状动脉和导致CAD 及MI，而anthracyclines 导致心脏衰竭，至于Herceptin被认为是和一种心脏抗体产生交互作用；不过，我们对于这些影响心脏的交互作用还需要更多资料，下一个研究要做的是真正进行所谓的art化疗 。
但现在希望听众带回去思考的讯息是，如果你对病患进行左胸放射线治疗，可能会增加CAD风险，特别是那些有高血压者。
对这些病患应确认他们有定期量测血压、胆固醇、和其他风险因子，她自认她不清楚到底应该多久检测这些病患一次才是恰当，不过在这次的追踪研究中有对此加以考量。
她结论指出，人们常在治疗多年后忘记自己有乳癌，我强调长期监测是必要的。
Recht医师在编辑评论中表示，和之前的研究不同之处只有一点，就是抽烟被发现是左胸放射线治疗之后发生冠心病的危险因子，而非高血压，我强烈鼓励病患应该积极治疗他们的高血压和
高血脂，同时，最好戒烟！
【研发中的新技术】
Harris医师解释道，仍有许多工作有待完成，放射肿瘤学仍有许多领域有争议，例如怎样才是降低放射线引起的心脏疾病的最佳方法。
研发中的新技术企图降低心脏的放射线曝露，包括加快局部胸部放射和调节放射线强度。
她总结指出，我们极力希望在放射区域确认没有心脏，但是对某些女性病患来说，难以达到这种目标。
J Clin Oncol。发表于August 14, 2006线上版。
Left-Sided Radiation for Breast Cancer Ups Heart Disease Risk
By Lisa Nainggolan
Medscape Medical News
August 17, 2006 — A new study shows that women with early-stage breast cancer who received radiation therapy to the left side of the chest were more likely to develop heart disease over the course of 2 decades than those who received right-sided radiation.
Eleanor E. R. Harris, MD, from the Moffitt Cancer Center and Research Institute in Tampa, Florida, and her team at the University of Pennsylvania — where she worked when conducting the research — report their findings online August 14 in the Journal of Clinical Oncology.
In an accompanying editorial, Abram Recht, MD, from the Harvard Medical School in Boston, Massachusetts, says the article by Dr. Harris and colleagues "is very important; it brings together long-term data on a relatively large number of fairly homogeneously treated patients with information on coexisting risk factors for coronary heart disease and determination of events gathered by review of individual medical records."
Hypertension Increases Risk of Radiation-Induced Heart Disease
Dr. Harris explained to Medscape that her study examined the use of contemporary radiation techniques for early breast cancer employed in the United States from the late 1970s onward, which were designed to minimize exposure to the heart, as previous research on this subject has involved outdated radiation techniques.
They set out to see whether 961 consecutive patients presenting from 1977 to 1994 had a higher rate of coronary artery disease (CAD) and cardiac death following left-sided radiation compared with right-sided radiation and whether any baseline cardiac risk factors interacted with left-sided radiation to increase the risk of CAD.
In the second decade after treatment, there was a higher rate of cardiac deaths in left-sided patients, with a cumulative risk of 6.4% for left-sided patients compared with 3.6% for right-sided patients at 20 years. There were also statistically higher rates of chest pain, CAD, and myocardial infarction (MI) diagnosed in left-sided patients (P < .002). Of the baseline cardiac risk factors, only hypertension was associated with a higher risk of CAD in left-sided patients.
Anthracyclines and Trastuzumab Were Not Involved
A limitation of the study, however, was that patients did not generally receive anthracyclines, which are now standard therapy for many breast cancer patients, nor did they get trastuzumab (Herceptin, Genentech), which is given to around 30% of patients. Both of these drug regimens can also cause cardiotoxicity, although Dr. Harris stressed that the mechanisms are different for all 3 treatment modalities.
"Radiation affects the coronary arteries and causes CAD and MI, whereas anthracyclines cause heart failure, and we think Herceptin interacts with a cardiac antibody. However, we definitely need more data on how these interact to affect the heart. The next study needs to be done with really state-of-the art chemotherapy," she explained.
"But the take-home message for now is that if you’ve had radiation to the left side of the chest, you have an increased risk of CAD, particularly if you are also hypertensive."
Such patients should make sure they have regular checks of blood pressure, cholesterol, and other risk factors, she noted, although she admitted that she does not know how often patients should get checked but is looking at this issue in a follow-up study.
"People often forget that they have had breast cancer and treatment as the years go on, but I can’t stress strongly enough that surveillance needs to be long-term," she concluded.
In his editorial, Dr. Recht says there is just one discrepancy with a previous study, in which smoking was found to be a risk factor for subsequent development of coronary heart disease following left-sided irradiation, but not hypertension. "I strongly encourage patients to vigorously treat their hypertension and hyperlipidemia — and, for God’s sake, stop smoking!" he says.
Newer Techniques Under Investigation
Dr. Harris explained that there is still much work to be done and there are many areas of debate among radiation oncologists as to how best to reduce the risk of radiation-induced heart disease.
Newer techniques under investigation to further reduce the exposure of the heart include accelerated partial-breast irradiation and intensity-modulated radiation therapy, she said.
"We are endeavoring to make sure there is no heart in the radiation field, but in some women, their anatomy makes this impossible," she concluded.
J Clin Oncol. Published online August 14, 2006.
作者：
Lisa Nainggolan 2007-6-20