MRI-guided single fraction ablative radiotherapy for early-stage breast cancer: a brachytherapy versus volumetric modulated arc therapy dosimetry study

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• 作者：Ramona K. Charaghvandi ; ^{r.charaghvandi@umcutrecht.nl" class="auth_mail" title="E-mail the corresponding author} ; Mariska D. den Hartogh ; Anne-Mar L.N. van Ommen ; Wilfred J.H. de Vries ; Vincent Scholten ; Marinus A. Moerland ; Marië ; lle E.P. Philippens ; Rogier I. Schokker ; Marco van Vulpen ; Bram van Asselen ; Desiré ; e H.J.G. van den Bongard
• 关键词：MRI-guidance ; Single fraction ; Ablative ; Breast cancer ; VMAT ; Interstitial multicatheter brachytherapy
• 刊名：Radiotherapy and Oncology
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：117
• 期：3
• 页码：477-482
• 全文大小：738 K

文摘

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.

Methods and materials

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 (PTV_CTV), and 20 Gy integrated boost to the PTV of the gross tumor volume (PTV_GTV). Treatment plans for IMB and VMAT were optimized for adequate target volume coverage and minimal organs at risk (OAR) dose.

Results

The median PTV_GTV/CTV receiving at least 95% of the prescribed dose was ⩾ 99% with both techniques. The median PTV_CTV unintentionally receiving 95% of the prescribed PTV_GTV dose was 65.4% and 4.3% with IMB and VMAT, respectively. OAR doses were comparable with both techniques.

Conclusion

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 PTV_CTV overdosage. Future studies have to confirm the clinical feasibility of the single fraction ablative approach.