Hypofractionated Hybrid Radiotherapy Techniques for Synchronous Bilateral Breast Cancer

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment

Background:

• Synchronous bilateral breast cancer (SBBC) presents unique treatment challenges.
• Hypofractionated radiotherapy regimens are increasingly used to optimize treatment schedules.
• Hybrid radiation therapy plans combine different techniques to improve outcomes.

Purpose of the Study:

• To perform a dosimetric comparison of four hybrid radiation therapy plans for SBBC.
• To evaluate these plans using a hypofractionated dose regimen.
• To determine the optimal hybrid plan for SBBC irradiation.

Main Methods:

• Four hybrid techniques (3DCRT+IMRT, 3DCRT+VMAT, IMRT+VMAT, VMAT+IMRT) were planned for 15 SBBC patients.
• A hypofractionated dose of 40.5 Gy in 15 fractions was prescribed.
• Plans were assessed based on planning target volume (PTV) and organs at risk (OARs) dosimetric parameters and a plan quality score.

Main Results:

• 3DCRT+VMAT and 3DCRT+IMRT plans showed superior PTV parameter results.
• The 3DCRT±IMRT plan offered better OARs protection.
• IMRT±VMAT and VMAT+IMRT plans increased low dose volumes to the heart and lungs; 3DCRT+VMAT required fewer monitor units and less treatment time.

Conclusions:

• The 3DCRT+VMAT hybrid plan demonstrated superior overall plan quality.
• This superiority was based on integrated dosimetric parameters of PTV and OARs.
• 3DCRT+VMAT is recommended as the preferred hybrid technique for SBBC treatment.