Department of Radiation Oncology, The Arthur G. James Cancer Hospital and Solove Research Institute, Ohio State University Comprehensive Cancer Center, Columbus, Ohio.
Department of Radiation Oncology, The Arthur G. James Cancer Hospital and Solove Research Institute, Ohio State University Comprehensive Cancer Center, Columbus, Ohio.
Int J Radiat Oncol Biol Phys. 2020 Dec 1;108(5):1159-1171. doi: 10.1016/j.ijrobp.2020.07.027. Epub 2020 Jul 22.
Clinical trials support adjuvant regional nodal irradiation (RNI) after breast-conserving surgery or mastectomy for patients with lymph node-positive breast cancer. Advanced treatment planning techniques (eg, intensity modulated radiation therapy [IMRT]) can reduce dose to organs at risk (OARs) in this situation. However, uncertainty persists about when IMRT is clinically indicated (vs 3-dimensional conformal radiation therapy [3DCRT]) for RNI. We hypothesized that an adaptive treatment planning algorithm (TPA) for IMRT adoption would allow OAR constraints for RNI to be met when 3DCRT could not without significantly changing toxicity and locoregional recurrence (LRR) patterns.
Since 2013, all RNI patients also underwent an adaptive TPA that began with 3DCRT and then changed to IMRT when OAR constraints (mean heart dose ≤500 cGy; ipsilateral lung V20 ≤35%) could not be met. Patients received 2 Gy/d to the prospectively contoured target volumes (including internal mammary nodes). We retrospectively evaluated the dosimetry and clinical outcomes of the treatment groups (IMRT vs 3DCRT). The primary endpoint was the cumulative incidence of LRR as the site of first recurrence, and we specifically address patterns of failure based on dose to the posterior supraclavicular nodal region (SCL-post).
Two hundred forty patients (60% stage III; mean 4.0 + nodes) underwent an adaptive-TPA for RNI after mastectomy (74%) or breast-conserving surgery (26%), resulting in 168 patients treated with 3DCRT and 72 patients treated with IMRT. There were 7 LRRs (2 IMRT, 5 3DCRT) resulting in 4-year LRR of 2.8% for IMRT versus 1.8% for 3DCRT (P = .99). Three patients (2 IMRT, 1 3DCRT) had SCL nodal failures (1 in the SCL-post).
An adaptive TPA for use of IMRT when 3DCRT does not meet critical OAR constraints resulted in rare high-grade toxicity and no difference in failure patterns between patients treated with IMRT and 3DCRT. These data should provide reassurance that IMRT maintains the therapeutic ratio by preserving cancer control outcomes without excess toxicity when 3DCRT fails to meet OAR constraints.
对于淋巴结阳性乳腺癌患者，保乳手术或乳房切除术之后的辅助区域淋巴结照射（RNI）有临床试验支持。先进的治疗计划技术（如调强放疗 [IMRT]）可以降低这种情况下的风险器官剂量（OARs）。然而，对于 RNI 时何时需要采用 IMRT（与三维适形放疗 [3DCRT] 相比）仍存在不确定性。我们假设，当 3DCRT 无法满足 OAR 限制而又不显著改变毒性和局部区域复发（LRR）模式时，采用自适应治疗计划算法（TPA）进行 IMRT 可以满足 RNI 的 OAR 限制。
自 2013 年以来，所有接受 RNI 的患者还接受了适应性 TPA，该 TPA 从 3DCRT 开始，当 OAR 限制（平均心脏剂量≤500cGy；同侧肺 V20≤35%）无法满足时，再转换为 IMRT。患者接受 2Gy/d 的前瞻性靶区照射（包括内乳淋巴结）。我们回顾性评估了两组（IMRT 与 3DCRT）的剂量学和临床结果。主要终点是作为首次复发部位的 LRR 的累积发生率，我们特别根据后锁骨上区（SCL-post）的剂量来探讨失败模式。
240 例患者（60%为 III 期；平均 4.0+淋巴结）接受了乳房切除术（74%）或保乳手术后的适应性 TPA 治疗 RNI，其中 168 例患者接受了 3DCRT 治疗，72 例患者接受了 IMRT 治疗。有 7 例局部区域复发（2 例 IMRT，5 例 3DCRT），导致 4 年局部区域复发率为 2.8%的 IMRT 与 1.8%的 3DCRT（P=.99）。3 例患者（2 例 IMRT，1 例 3DCRT）发生锁骨上淋巴结失败（1 例在 SCL-post）。
当 3DCRT 无法满足关键 OAR 限制时，采用自适应 TPA 进行 IMRT 治疗，导致严重程度较高的毒性罕见，且接受 IMRT 和 3DCRT 治疗的患者失败模式无差异。这些数据应提供保证，即当 3DCRT 无法满足 OAR 限制时，采用 IMRT 可以保持治疗比率，保留癌症控制结果，而不会增加毒性。
