Abstract
Purpose To compare five techniques for the postmastectomy radiotherapy (PMRT) with simultaneous integrated boost (SIB). Materials and Methods Twenty patients with left-sided breast cancer were retrospectively selected. Five treatment plans were created for each patient: TomoDirect (TD), unblocked helical TomoTherapy (unb-HT), blocked HT (b-HT), hybrid intensity-modulated radiotherapy (hy-IMRT), and fixed-field IMRT (ff-IMRT). A dose of 50.4 Gy in 28 fractions to PTVtotal and 60.2 Gy in 28 fractions to PTVboost were prescribed. The dosimetric parameters for targets and organs at risk (OARs), the normal tissue complication probability (NTCP), the second cancer complication probability (SCCP) for OARs, and the treatment efficiency were assessed and compared. Results TD plans and hy-IMRT plans had similar good dose coverage and homogeneity for both PTVboost and PTVtotal and superior dose sparing for the lungs and heart. The ff-IMRT plans had similar dosimetric results for the target volumes compared with the TD and hy-IMRT plans, but gave a relatively higher NTCP and SCCP for the lungs. The unb-HT plans exhibited the highest OAR mean dose, highest NTCP for the lungs (0.97 ± 1.25‰) and heart (4.58 ± 3.62%), and highest SCCP for the lungs (3.57 ± 0.05%) and contralateral breast (2.75 ± 0.29%) among all techniques. The b-HT plans significantly outperformed unb-HT plans with respect to the sparing of the lungs and heart. This technique also showed the best conformity index (0.73 ± 0.08) for PTVboost and the optimal NTCP for the lungs (0.03 ± 0.03‰) and heart (0.61 ± 0.73%). Concerning the delivery efficiency, the hy-IMRT and ff-IMRT achieved much higher delivery efficiency compared with TomoTherapy plans. Conclusion Of the five techniques studied, TD and hy-IMRT are considered the preferable options for PMRT with SIB for left-sided breast cancer treatment and can be routinely applied in clinical practice.
Highlights
Postmastectomy radiotherapy (PMRT) plays a critical role in breast cancer treatment
The isodose distributions and DVHs for one typical patient were shown in Figures 1 and 2, respectively
For PTVboost, we found no significant difference in D98%, D95%, and V110% (p > 0:05) among the five techniques, except that D98% in unblocked helical TomoTherapy (unb-helical TomoTherapy (HT)) (59:49 ± 0:23 Gy) and in TD (59:45 ± 0:30 Gy) plans was slightly higher than that in fixed-field IMRT (ff-IMRT) (59:22 ± 0:33 Gy)
Summary
Postmastectomy radiotherapy (PMRT) plays a critical role in breast cancer treatment. Previous studies have demonstrated a significant improvement in overall and local survival after PMRT in breast cancer patients [1, 2]. The use of a tumorbed boost scheme has shown the further improvement in the local-regional control for patients with high-risk features [3]. There is lack of randomized data to guide the boost dose setting, the boost technique is accepted as a routine practice in many centers [3,4,5]. According to our local protocol, the simultaneous integrated boost (SIB). The delivery of PMRT with SIB for patients is challenging due to the large target volume size, high prescription dose, and proximity to critical organs, especially for patients who suffer from leftsided breast cancer. It is of great importance to find the optimal technique for PMRT with SIB
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
