Study on dose optimization strategy of dynamic intensity-modulated radiotherapy based on the inner edge tangent field for the target area after breast-conserving surgery for left-sided breast cancer

doi:10.3760/cma.j.cn371439-20250507-00118

Abstract

Abstract:

Objective To explore the dose optimization strategy of dynamic intensity-modulated radiotherapy （dIMRT） based on the inner edge tangential field （IETF） for the target area after breast-conserving surgery for left-sided breast cancer. Methods The localization CT and target organ at risk （OAR） data of 36 patients with left-sided breast cancer treated with breast-conserving surgery and postoperative radiotherapy in the Department of Radiotherapy of Yunnan Cancer Hospital from August 2023 to October 2024 were retrospectively selected. Two dIMRT schedules， conventional tangential field （CTF）-dIMRT and IETF-dIMRT， were designed for each patient； The target dose and the OAR dose of the two groups were counted and analyzed. Results For CTF-dIMRT and IETF-dIMRT， the D_98% of the target area were （47.36±0.88） and （47.61±0.81） Gy， and the D_50% were （52.08±0.23） and （52.01±0.22） Gy， the conformity index （CI） were 0.82±0.03 and 0.84±0.03， with statistically significant differences （t=-3.45， P=0.001； t=2.28， P=0.029； t=-6.24， P<0.001）. The D_2% were （53.83±0.33） and （53.89±0.42） Gy， the homogeneity index （HI） were 0.12±0.02 and 0.12±0.02， with no statistically significant difference （t=-1.11， P=0.276； t=1.89， P=0.067）. For CTF-dIMRT and IETF-dIMRT， the V₅ of left lung were （35.40±7.77） % and （31.44±6.01） %， the V₂₀ were （12.69±2.84） % and （11.48±2.22） %， the D_mean were （8.15±1.42） and （7.39±1.13） Gy， with statistically significant differences （t=6.92， P<0.001； t=6.79， P<0.001； t=9.10， P<0.001）. The heart D_mean were （4.99±1.15） and （4.29±1.00） Gy， the right lung D_mean were （1.24±0.12） and （1.15±0.11） Gy， the right breast D_meanwere （2.34±1.01） and （3.26±1.54） Gy， the spinal cord D₂ were （1.26±0.13） and （1.22±0.12） Gy， with statistically significant differences （t=7.88， P<0.001； t=6.66， P<0.001； t=-6.85， P<0.001； t=2.76， P=0.009）. Conclusions Both IETF-dIMRT and CTF-dIMRT can fully meet clinical requirements. Compared with CTF-dIMRT， IETF-dIMRT after breast-conserving surgery for left-sided breast cancer has more benefits in terms of target dose and OAR protection.

Key words: Unilateral breast neoplasms, Radiotherapy， intensity-modulated, Radiation dosage, Conventional tangential field, Inner edge tangential field

Zhao Biao, Zhu Yupu, Zhang Yating, Yuan Meifang, Li Han, Yang Yi, Sun Chaoxi. Study on dose optimization strategy of dynamic intensity-modulated radiotherapy based on the inner edge tangent field for the target area after breast-conserving surgery for left-sided breast cancer[J]. Journal of International Oncology, 2025, 52(11): 689-694.

Figures/Tables 4

References 29

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