Beaton Laura, Bergman Alanah, Nichol Alan, Aparicio Maria, Wong Graham, Gondara Lovedeep, Speers Caroline, Weir Lorna, Davis Margot, Tyldesley Scott
Department of Radiation Oncology, BC Cancer Agency, Vancouver Centre, Vancouver, British Columbia, Canada.
Department of Medical Physics, BC Cancer Agency, Vancouver Centre, Vancouver, British Columbia, Canada.
Clin Transl Radiat Oncol. 2019 Aug 13;19:39-45. doi: 10.1016/j.ctro.2019.08.001. eCollection 2019 Nov.
Breast/chest wall irradiation (RT) increases risk of cardiovascular death. International Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) guidelines state for partial heart irradiation a "V25Gy <10% will be associated with a <1% probability of cardiac mortality" in long-term follow-up after RT. We assessed whether women treated with breast/chest wall RT 10-years ago who died of cardiovascular disease (CVD) violated QUANTEC guidelines.
MATERIALS/METHODS: A population-based database identified all cardiovascular deaths in women with early-stage breast cancer <80 years, treated with adjuvant breast/chest wall RT from 2002 to 2006. Ten-year rate of cardiovascular death was calculated using a Kaplan-Meier method. Patients were matched on a 2:1 basis with controls that did not die of CVD. For left-sided cases, the heart and left anterior descending (LAD) artery were retrospectively delineated. Dose-volume histograms were calculated, and heart V25Gy compared to QUANTEC guidelines.
5249 eligible patients received breast/chest wall RT from 2002 to 2006: 76 (1.4% at 10-years) died of CVD by June 2015. Forty-two patients received left-sided RT (1.7% CVD death at 10-years), 34 right-sided RT (1.3% at 10-years). Heart V25Gy did not exceed 10% in any left-sided cases. No cardiac dosimetry parameter distinguished left-sided cases from controls.
QUANTEC guidelines were not violated in any patient that died of CVD after left-sided RT. The risk of radiation induced cardiac death at 10-years appears to be very low if MHD is <3.3 Gy and maximum LAD dose (EQD2 Gy) is <45.4 Gy. Further studies are needed to evaluate heart and LAD constraints in the CT-planning era.
乳腺/胸壁放疗（RT）会增加心血管死亡风险。国际临床正常组织效应定量分析（QUANTEC）指南指出，对于部分心脏放疗，在放疗后的长期随访中，“V25Gy＜10%将与＜1%的心脏死亡率相关”。我们评估了10年前接受乳腺/胸壁放疗且死于心血管疾病（CVD）的女性是否违反了QUANTEC指南。
材料/方法：一个基于人群的数据库确定了2002年至2006年接受辅助性乳腺/胸壁放疗的80岁以下早期乳腺癌女性中的所有心血管死亡病例。使用Kaplan-Meier方法计算10年心血管死亡率。患者与未死于CVD的对照组按2:1的比例进行匹配。对于左侧病例，对心脏和左前降支（LAD）动脉进行回顾性勾画。计算剂量体积直方图，并将心脏V25Gy与QUANTEC指南进行比较。
2002年至2006年，5249例符合条件的患者接受了乳腺/胸壁放疗：到2015年6月，76例（10年时为1.4%）死于CVD。42例患者接受左侧放疗（10年时CVD死亡率为1.7%），34例接受右侧放疗（10年时为1.3%）。在任何左侧病例中，心脏V25Gy均未超过10%。没有心脏剂量学参数能区分左侧病例和对照组。
左侧放疗后死于CVD的任何患者均未违反QUANTEC指南。如果平均心脏剂量（MHD）＜3.3 Gy且最大LAD剂量（等效剂量2 Gy）＜45.4 Gy，10年时辐射诱发心脏死亡的风险似乎非常低。需要进一步研究以评估CT规划时代的心脏和LAD限制。
