Charaghvandi Ramona K, den Hartogh Mariska D, van Ommen Anne-Mar L N, de Vries Wilfred J H, Scholten Vincent, Moerland Marinus A, Philippens Mariëlle E P, Schokker Rogier I, van Vulpen Marco, van Asselen Bram, van den Bongard Desirée H J G
Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
Department of Radiotherapy, University Medical Center Utrecht, The Netherlands.
Radiother Oncol. 2015 Dec;117(3):477-82. doi: 10.1016/j.radonc.2015.09.023. Epub 2015 Oct 1.
A radiosurgical treatment approach for early-stage breast cancer has the potential to minimize the patient's treatment burden. The dosimetric feasibility for single fraction ablative radiotherapy was evaluated by comparing volumetric modulated arc therapy (VMAT) with an interstitial multicatheter brachytherapy (IMB) approach.
The tumors of 20 patients with early-stage breast cancer were delineated on a preoperative contrast-enhanced planning CT-scan, co-registered with a contrast-enhanced magnetic resonance imaging (MRI), both in radiotherapy supine position. A dose of 15 Gy was prescribed to the planned target volume of the clinical target volume (PTVCTV), and 20 Gy integrated boost to the PTV of the gross tumor volume (PTVGTV). Treatment plans for IMB and VMAT were optimized for adequate target volume coverage and minimal organs at risk (OAR) dose.
The median PTVGTV/CTV receiving at least 95% of the prescribed dose was ⩾99% with both techniques. The median PTVCTV unintentionally receiving 95% of the prescribed PTVGTV dose was 65.4% and 4.3% with IMB and VMAT, respectively. OAR doses were comparable with both techniques.
MRI-guided single fraction radiotherapy with an integrated ablative boost to the GTV is dosimetrically feasible with both techniques. We perceive IMB less suitable for clinical implementation due to PTVCTV overdosage. Future studies have to confirm the clinical feasibility of the single fraction ablative approach.
早期乳腺癌的放射外科治疗方法有可能将患者的治疗负担降至最低。通过比较容积调强弧形放疗（VMAT）与组织间多导管近距离放疗（IMB）方法，评估单次分割消融放疗的剂量学可行性。
在放疗仰卧位下，对20例早期乳腺癌患者的肿瘤在术前增强扫描的计划CT上进行勾画，并与增强磁共振成像（MRI）进行配准。临床靶体积（CTV）的计划靶体积（PTVCTV）处方剂量为15 Gy，大体肿瘤体积（GTV）的PTV给予20 Gy的累积剂量增加。对IMB和VMAT的治疗计划进行优化，以实现足够的靶体积覆盖和最小的危及器官（OAR）剂量。
两种技术中，接受至少95%处方剂量的PTVGTV/CTV中位数均⩾99%。IMB和VMAT中，意外接受95% PTVGTV处方剂量的PTVCTV中位数分别为65.4%和4.3%。两种技术的OAR剂量相当。
两种技术在MRI引导下对GTV进行单次分割放疗并联合消融剂量增加在剂量学上都是可行的。由于PTVCTV剂量过高，我们认为IMB不太适合临床应用。未来的研究必须证实单次分割消融方法的临床可行性。
