Thomsen Mette S, Alsner Jan, Nielsen Hanne M, Jakobsen Erik H, Nielsen Mette H, Møller Mette, Pedersen Anders N, Yates Esben, Berg Martin, Lorenzen Ebbe, Jensen Ingelise, Josipovic Mirjana, Overgaard Jens, Offersen Birgitte V
Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark.
Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark.
Radiother Oncol. 2022 Dec;177:231-235. doi: 10.1016/j.radonc.2022.09.024. Epub 2022 Oct 17.
The relation between breast induration grade 2-3 at 3 years after radiation therapy and irradiated breast volume was investigated for patients in the Danish Breast Cancer Group (DBCG) Partial Breast Irradiation (PBI) trial. METHODS Treatment plan data was obtained from the Danish radiotherapy plan database. Dosimetric parameters for breast and organs at risk were determined. Breast induration data was obtained from the DBCG database. The volume of the whole breast (CTVp_breast) treated to various dose levels was determined for treatment plans in both arms. Logistic regression was used to assess the frequency of induration on breast volume irradiated to ≥40 Gy. RESULTS PBI and WBI was given to 433 and 432 patients, respectively. Median and interquartile ranges (IQR) for CTVp_breast were 710 mL (467-963 mL; PBI) and 666 mL (443-1012 mL; WBI) (p = 0.98). Median and IQR for CTVp_breast treated to ≥40 Gy was 24.9% (18.6-32.6%; PBI) and 59.8% (53.6-68.5%; WBI). Grade 2-3 induration was observed in 5% (PBI) and 10% (WBI) of the patients. A dose-response relationship was established between irradiated breast volume and frequency of breast induration. From the model, 5% and 10% risks of breast induration were observed for ≥40 Gy delivered to CTVp_breast volumes of 177 mL (95%CI, 94-260 mL) and 426 mL (95%CI, 286-567 mL), respectively. CONCLUSION The frequency of breast induration increased significantly with increasing irradiated breast volume, strongly favouring small volumes and PBI. Thus, treated breast volume - not the breast size itself - is the risk factor for induration. This is the first report directly linking the 40 Gy irradiated breast volume to breast induration.
在丹麦乳腺癌协作组（DBCG）部分乳腺照射（PBI）试验中，研究了放疗3年后2 - 3级乳腺硬结与照射乳腺体积之间的关系。方法从丹麦放射治疗计划数据库中获取治疗计划数据。确定乳腺及危及器官的剂量学参数。从DBCG数据库中获取乳腺硬结数据。确定双臂治疗计划中接受不同剂量水平照射的全乳（CTVp_breast）体积。采用逻辑回归评估照射至≥40 Gy的乳腺体积上硬结的发生频率。结果分别对433例和432例患者进行了PBI和全乳照射（WBI）。CTVp_breast的中位数和四分位数间距（IQR）分别为710 mL（467 - 963 mL；PBI）和666 mL（443 - 1012 mL；WBI）（p = 0.98）。接受≥40 Gy照射的CTVp_breast的中位数和IQR分别为24.9%（18.6 - 32.6%；PBI）和59.8%（53.6 - 68.5%；WBI）。5%（PBI）和10%（WBI）的患者出现2 - 3级硬结。在照射乳腺体积与乳腺硬结发生频率之间建立了剂量反应关系。根据该模型，当CTVp_breast体积分别为177 mL（95%CI，94 - 260 mL）和426 mL（95%CI，286 - 567 mL）时，接受≥40 Gy照射，乳腺硬结的风险分别为5%和10%。结论乳腺硬结的发生频率随照射乳腺体积的增加而显著增加，强烈支持小体积照射和PBI。因此，接受治疗的乳腺体积而非乳腺本身大小是硬结的危险因素。这是首次直接将40 Gy照射乳腺体积与乳腺硬结联系起来的报告。
