Left ventricle and left Anterior Descending Coronary Artery Radiation Dose in Patient Receiving Adjuvant Radiotherapy for Left Breast Cancer in Prone Position, A Prospective Study

Saleh, Heba Refaat Anwar; El-Sheshtawy, Wael Helmy; El-Agamawi, Ahmed Yousry

doi:https://doi.org/10.21608/aimj.2025.446491

Left ventricle and left Anterior Descending Coronary Artery Radiation Dose in Patient Receiving Adjuvant Radiotherapy for Left Breast Cancer in Prone Position, A Prospective Study

Document Type : Original Article

Authors

Department of Clinical Oncology & Nuclear Medicine, Faculty of Medicine, Al-Azhar University

https://doi.org/10.21608/aimj.2025.446491

Abstract

Background: Adjuvant breast irradiation in the supine posture for left-sided breast cancer has a late cardiac damage. Treatment in the prone position is used to minimize radiation exposure to cardiac structures.
Aim: This study aims to evaluate the radiation dosage to the left ventricle(LV)and left anterior descending (LAD)coronary artery in prone position irradiation versus supine position, additionally evaluating associated acute toxicities.
Patients and Methodology: Females with early-stage left breast cancer who underwent breast-conserving surgery(BCS)and needed postoperative radiation without nodal irradiation were included in this research. Both supine and prone plans were used for all patients for dosimetric comparison between positions. However, treatment was received in the prone position, with a total dose of 40Gy in 15 fractions over 3weeks.
Results: The study included 55 women, all managed with BCS, with a median age of 49 years, (34.5%)of whom 34.5% had large breast size(≥1600cm³). The dosimetric comparison between the prone and supine positions revealed a significantly better conformity index in the prone position(mean 0.91 ± 0.13SD)versus the supine position (mean 0.77 ± 0.11SD), with p-value<0.0001. comparing prone and supine positions, critical organ dosage were noticeably lower in prone arm: left lungV16( 0.45% ± 1.29SD)versus(19.29% ± 6.30SD), heart Dmean(1.57Gy ± 0.63SD)versus(5.05Gy ± 2.30SD), LAD Dmax(15.19Gy ± 2.71SD)versus(38.71Gy ± 2.35SD), and LV-V5( 4.07% ± 4.59SD)versus(26.67% ± 15.77SD)respectively(p-values<0.0001 for all parameters). Moreover, no Grade 3-4 acute toxicities.The incidence of Grade 1–2 acute skin toxicity, fatigue, edema, and pain were100%,65%,86%, and 46%, respectively.
Conclusion: In all study group, patients treated in the prone position and experienced less radiation exposure to key structures, with no grade III-IV toxicities,compared to the supine position. Nonetheless, larger clinical trials are needed.

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