Sato Kazuhiko, Mizuno Yoshio, Fuchikami Hiromi, Kato Masahiro, Shimo Takahiro, Kubota Jun, Takeda Naoko, Inoue Yuko, Seto Hiroshi, Okawa Tomohiko
Department of Breast Oncology, Tokyo-West Tokushukai Hospital, Tokyo.
Department of Radiation Oncology, Tokyo-West Tokushukai Hospital, Tokyo.
J Contemp Brachytherapy. 2015 Feb;7(1):23-8. doi: 10.5114/jcb.2014.47891. Epub 2015 Jan 14.
Breast conserving surgery (BCS) followed by whole breast irradiation (WBI) is the standard of care for breast cancer patients. However, there is a risk of coronary events with WBI therapy. In this study, we compared the radiation dose in the left anterior descending artery (LAD) in patients receiving partial breast irradiation (PBI) with WBI.
We evaluated consecutive patients who underwent adjuvant radiotherapy after BCS between October 2008 and July 2014. Whole breast irradiation patients received 50 Gy in fractions of 2 Gy to the entire breast. Partial breast irradiation was performed using multicatheter brachytherapy at a dose of 32 Gy in eight fractions. The mean and maximal cumulative doses to LAD were calculated. The radiotherapeutic biologically effective dose of PBI was adjusted to WBI, and radiation techniques were compared.
Of 379 consecutive patients with 383 lesions receiving radiotherapy (151 WBI and 232 PBI lesions), 82 WBI and 100 PBI patients were analyzed. In WBI patients, the mean and maximal cumulative doses for left-sided breast cancer (2.13 ± 0.11 and 8.19 ± 1.21 Gy, respectively) were significantly higher than those for right-sided (0.37 ± 0.02 and 0.56 ± 0.03 Gy, respectively; p < 0.0001). In PBI patients with left-sided breast cancer, the doses for tumors in inner quadrants or central location (2.54 ± 0.21 and 4.43 ± 0.38 Gy, respectively) were significantly elevated compared to outer quadrants (1.02 ± 0.17 and 2.10 ± 0.29 Gy, respectively; p < 0.0001). After the adjustment, the doses in PBI patients were significantly reduced in patients with tumors only in outer quadrants (1.12 ± 0.20 and 2.43 ± 0.37 Gy, respectively; p = 0.0001).
Tumor control and dose to LAD should be considered during treatment since PBI may reduce the risk of coronary artery disease especially in patients with lateral tumors in the left breast.
保乳手术（BCS）联合全乳照射（WBI）是乳腺癌患者的标准治疗方案。然而，WBI治疗存在发生冠状动脉事件的风险。在本研究中，我们比较了接受部分乳腺照射（PBI）和WBI的患者左前降支动脉（LAD）的辐射剂量。
我们评估了2008年10月至2014年7月期间接受BCS术后辅助放疗的连续患者。全乳照射患者对整个乳房给予50 Gy，每次2 Gy。部分乳腺照射采用多导管近距离放疗，剂量为32 Gy，分8次给予。计算LAD的平均和最大累积剂量。将PBI的放射治疗生物等效剂量调整为WBI，并比较放射技术。
在379例连续接受放疗的383个病灶患者中（151个WBI病灶和232个PBI病灶），分析了82例WBI患者和100例PBI患者。在WBI患者中，左侧乳腺癌的平均和最大累积剂量（分别为2.13±0.11和8.19±1.21 Gy）显著高于右侧（分别为0.37±0.02和0.56±0.03 Gy；p<0.0001）。在左侧乳腺癌的PBI患者中，内象限或中央部位肿瘤的剂量（分别为2.54±0.21和4.43±0.38 Gy）显著高于外象限（分别为1.02±0.17和2.10±0.29 Gy；p<0.0001）。调整后，仅外象限有肿瘤的PBI患者剂量显著降低（分别为1.12±0.20和2.43±0.37 Gy；p = 0.0001）。
治疗期间应考虑肿瘤控制和LAD剂量，因为PBI可能降低冠状动脉疾病的风险，尤其是左乳外侧肿瘤患者。
