Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.
Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.
Radiat Oncol. 2017 Jun 20;12(1):103. doi: 10.1186/s13014-017-0843-7.
To investigate the patterns of post-lumpectomy seroma volume (SV) change and related clinical factors to determine the benefits of adaptive planning in magnetic resonance imaging (MRI)-guided partial breast irradiation (PBI).
MRI data obtained from 37 women with early breast cancer acquired at simulation and at the 1st, 6th, and 10th fractions were analyzed. The planning target volume (PTV) was defined as unequal margins of 10-15 mm added according to the directional surgical margin status of each seroma. Treatment was performed using a 0.35 T MRI-guided radiotherapy system. Univariate analysis was performed to assess the correlations between SV change rate and clinical factors. Seroma and PTV for adaptive planning were based on the images obtained at the 6th fraction.
The average time intervals between surgery-simulation, simulation-1st, 1st-6th, and 6th-10th fractions were 23.1, 8.5, 7.2, and 5.9 days, respectively. Of the 37 patients, 33 exhibited decreased SV over the treatment period. The mean SV of these 33 patients decreased from 100% at simulation to 60, 48, and 40% at each MRI scan. In most cases (26/33), the logarithm of SV was inversely proportional to the elapsed time from surgery (R > 0.90, Pearson's correlation test). The volume of spared normal tissue from adaptive radiotherapy was proportional to the absolute change in SV (R = 0.89, Pearson's correlation test).
Seromas exhibit exponential shrinkage over the course of PBI. In patients receiving PBI, frequent monitoring of SV could be helpful in decision-making regarding adaptive planning, especially those with a large seroma.
本研究旨在探讨保乳术后血清肿体积（SV）变化的模式及相关临床因素，以评估自适应计划在磁共振成像（MRI）引导下部分乳腺照射（PBI）中的获益。
对 37 例早期乳腺癌患者的 MRI 数据进行分析，这些患者分别在模拟定位、第 1、6 和 10 次分次时进行了 MRI 扫描。计划靶区（PTV）定义为根据每个血清肿的定向手术切缘状态，在 10-15mm 的不等边界上进行扩展。治疗采用 0.35T MRI 引导放疗系统。采用单因素分析评估 SV 变化率与临床因素之间的相关性。自适应计划的血清肿和 PTV 基于第 6 次分次时的图像。
手术-模拟、模拟-第 1 次、第 1 次-第 6 次和第 6 次-第 10 次分次的平均时间间隔分别为 23.1、8.5、7.2 和 5.9 天。37 例患者中，33 例患者在治疗期间 SV 减少。这 33 例患者的 SV 平均值从模拟时的 100%下降到每次 MRI 扫描时的 60%、48%和 40%。在大多数情况下（26/33），SV 的对数与从手术开始的时间呈反比（R>0.90，Pearson 相关检验）。自适应放疗中节省的正常组织体积与 SV 的绝对变化成正比（R=0.89，Pearson 相关检验）。
保乳术后血清肿体积呈指数性缩小。在接受 PBI 的患者中，频繁监测 SV 可能有助于自适应计划的决策，特别是那些血清肿较大的患者。
