Presence of Tissue Expanders Does Not Affect Radiotherapy Dose Distribution to Heart and Lungs

Area of Science:

• Oncology
• Radiotherapy
• Medical Physics

Background:

• Postmastectomy radiotherapy (PMRT) is increasingly used for breast cancer patients, particularly node-positive cases.
• While PMRT risks to reconstructed breasts are known, its effect on nearby organs like the heart and lungs when using tissue expanders (TEs) is unclear.

Purpose of the Study:

• To investigate the influence of TEs on radiation dose distribution to the heart and lungs during PMRT.
• To explore the correlation between TE fill volume and radiation dose to organs at risk.
• To analyze the relationship between Body Mass Index (BMI) and radiation dose to the heart.

Main Methods:

• Retrospective analysis of 124 patients who underwent mastectomy and PMRT with 3D CT planning.
• Comparison of radiation dose statistics for the ipsilateral lung and heart between mastectomy alone and mastectomy with TE groups.
• Analysis of dose statistics based on TE intraoperative fill volumes (≤60 mL vs. >60 mL).
• Correlation analysis between dose statistics and patient BMI.

Main Results:

• No significant differences in lung or heart radiation doses were observed between patients with and without TEs.
• TE fill volume did not significantly affect radiation dose metrics to the lungs or heart.
• A significant positive correlation was found between BMI and the maximum heart radiation dose (P=0.03).

Conclusions:

• The presence of TEs and their fill volume do not alter radiation dose distribution to the heart and lungs during PMRT.
• Increased BMI is associated with a higher maximum radiation dose to the heart in patients undergoing PMRT.