宫颈癌调强放疗中骨髓保护的最佳剂量限制策略。
Optimal dose limitation strategy for bone marrow sparing in intensity-modulated radiotherapy of cervical cancer.
机构信息
Department of Radiation and Medical Oncology, Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Zhongnan Hospital of Wuhan University, Wuhan, China.
Department of Radiation Oncology, William Beaumont Hospital, 3601 W. 13 Mile Rd, Royal Oak, MI, 48073, USA.
出版信息
Radiat Oncol. 2019 Aug 5;14(1):118. doi: 10.1186/s13014-019-1324-y.
BACKGROUND
To quantify the dosimetric parameters of different bone marrow sparing strategies and to determine the optimal strategy for cervical cancer patients undergoing postoperative intensity-modulated radiotherapy (IMRT).
METHODS
Fifteen patients with cervical cancer were selected for analysis. The planning target volume (PTV) and the organs at risks (OAR) including small bowel, bladder, rectum, femoral heads, os coxae (OC), lumbosacral spine (LS) and bone marrow (BM) were contoured. For each patient, four IMRT plans with different strategies were generated, including one plan without BM as the dose-volume constraint, namely IMRT (N) plan, and three bone marrow sparing (BMS-IMRT) plans. The three BMS-IMRT plans used the BM, OC, OC and LS respectively, as the BM OAR, namely as IMRT (BM), IMRT (OC) and IMRT (OC + LS) plans. Dose volumes for the target and the OARs were compared using analysis of variance (ANOVA).
RESULTS
Compared with IMRT (N) plans, the dose to the small bowel, bladder, rectum and femoral heads showed no increase in the three BMS-IMRT plans. However, the irradiated dose to BM, OC and LS significantly decreased. In particular, the mean dose of BM, OC and LS decreased by about 5Gy (p < 0.05) in IMRT (BM) plans while the average volume receiving ≥20, ≥30, ≥40Gy decreased by 7.1-24.2%. The LS volume receiving 40Gy showed the highest decrease (about 31.2%, p < 0.05) in IMRT (OC + LS) plans. On the other hand, in comparison with IMRT (BM), IMRT (OC) reduced the dose volume of to the OC, but increased the dose to LS while IMRT (OC + LS) plans reduced both the OC and the LS volume at all dose levels. Specifically, the V of OC and LS in the IMRT (OC + LS) plan decreased by 11.5 and 11.2%, respectively.
CONCLUSION
By introducing the os coxae and lumbosacral spine as the dose-volume constraints, the IMRT plans exhibited the best sparing of the bone marrow without compromising the dose to surrounding normal structures. Therefore, we recommend adding the os coxae and lumbosacral spine as the BM OAR in such plans.
背景
为了量化不同骨髓保护策略的剂量学参数，并确定宫颈癌患者术后调强放疗（IMRT）的最佳策略。
方法
选择 15 例宫颈癌患者进行分析。勾画计划靶区（PTV）和危及器官（OAR），包括小肠、膀胱、直肠、股骨头、骨盆（OC）、腰骶部脊柱（LS）和骨髓（BM）。对于每位患者，生成了四种不同策略的 IMRT 计划，包括一个不将 BM 作为剂量-体积限制的计划，即 IMRT（N）计划，以及三个骨髓保护（BMS-IMRT）计划。三个 BMS-IMRT 计划分别将 BM、OC、OC 和 LS 用作 BM OAR，即 IMRT（BM）、IMRT（OC）和 IMRT（OC+LS）计划。使用方差分析（ANOVA）比较靶区和 OAR 的剂量体积。
结果
与 IMRT（N）计划相比，三个 BMS-IMRT 计划中小肠、膀胱、直肠和股骨头的剂量没有增加。然而，BM、OC 和 LS 的受照剂量显著降低。特别是，BM、OC 和 LS 的平均剂量降低了约 5Gy（p<0.05），而接受≥20、≥30、≥40Gy 的体积分别降低了 7.1-24.2%。LS 接受 40Gy 的体积在 IMRT（OC+LS）计划中下降幅度最大（约 31.2%，p<0.05）。另一方面，与 IMRT（BM）相比，IMRT（OC）降低了 OC 的剂量体积，但增加了 LS 的剂量，而 IMRT（OC+LS）计划则降低了 OC 和 LS 在所有剂量水平的体积。具体而言，IMRT（OC+LS）计划中 OC 和 LS 的 V 分别减少了 11.5%和 11.2%。
结论
通过将骨盆和腰骶部脊柱作为剂量-体积限制，IMRT 计划在不影响周围正常结构剂量的情况下，最大限度地保护了骨髓。因此，我们建议在这些计划中将骨盆和腰骶部脊柱作为 BM OAR。
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