Abstract
MammoSite balloon brachytherapy is a relatively new technique for partial breast irradiation. The present paper focuses on the treatment planning, dosimetry, and quality assurance aspects of that treatment, based on the Radiation Therapy Oncology Group 0413 randomized prospective trial (RTOG 0413) protocol. We investigate the usefulness of evaluating implants for treatment appropriateness according to the full set of RTOG criteria as compared with the manufacturer's guidelines. We describe our methods to improve MammoSite balloon implants that would otherwise not comply with the protocol. The initially acquired computed tomography (CT) images are evaluated for tissue conformance, balloon surface–to–skin distance, and balloon symmetry. If the implant fails to meet the foregoing criteria, corrective action such as delay in the CT scan, balloon manipulation, or fluid volume adjustment is taken, and the patient is re‐scanned. If the corrective action appears to be successful, three dimensional treatment planning and dose–volume histogram analysis is performed to evaluate the geometric and dosimetric parameters with regard to the RTOG 0413 protocol. The evaluated parameters include• volume ratio of the lumpectomy cavity to the ipsilateral breast,• target volume coverage,• tissue–balloon conformance,• balloon symmetry,• minimal balloon surface–to–skin distance,• maximum skin dose, and• normal breast tissue dose–volume parameters V150 and V200.Among our implants, 21.7% did not initially meet the RTOG 0413 acceptance criteria. Asymmetry and poor conformance values reduce the target volume coverage, and so an implant with moderate conformance and asymmetry can be within the manufacturer's guidelines, but still not meet the RTOG criteria. Our intervention corrected all but one of the implants that failed to meet the criteria. Manipulating the cavity and adjusting the balloon volume may salvage an implant and meet the strict geometric and dosimetric criteria imposed by the RTOG 0413 protocol.PACS number: 7.53.Jw
Highlights
Breast-conserving therapy (BCT) is an accepted treatment option for early-stage breast cancer
Manipulating the cavity and adjusting the balloon volume may salvage an implant and meet the strict geometric and dosimetric criteria imposed by the Radiation Therapy Oncology Group (RTOG) 0413 protocol
Other studies report that BCT is underutilized in certain patient populations.[3,4,5] The time commitment required for this treatment regimen has been suggested to be one of the reasons that many patients do not receive BCT.[6]. Several promising studies indicate that accelerated partial breast irradiation (PBI) to the tumor bed provides local control that is equivalent to the standard therapy in a carefully selected group of patients.[7]. The PBI technique offers the advantage of shortened treatment duration and increased patient convenience
Summary
Breast-conserving therapy (BCT) is an accepted treatment option for early-stage breast cancer. Other studies report that BCT is underutilized in certain patient populations.[3,4,5] The time commitment required for this treatment regimen has been suggested to be one of the reasons that many patients do not receive BCT.[6] Several promising studies indicate that accelerated partial breast irradiation (PBI) to the tumor bed provides local control that is equivalent to the standard therapy in a carefully selected group of patients.[7] The PBI technique offers the advantage of shortened treatment duration and increased patient convenience. The National Surgical Adjuvant Breast and Bowel Project (NSABP) and the Radiation Therapy Oncology Group (RTOG) have combined efforts and opened a phase III randomized trial (NSABP B-39/RTOG 0413)(7) to evaluate the effectiveness of PBI as compared with the broadly accepted technique of whole-breast irradiation in providing equivalent local tumor control in the breast following lumpectomy for early-stage breast cancer. Normal tissues receive entrance and exit dose with 3D-CRT
Sign-in/Register to view highlights & summary 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.
