KEY POINTS
- This retrospective analysis included 484 consecutive patients receiving adjuvant breast or chest-wall radiotherapy between June 2020 and June 2023. Median age was 61 years, 87.4% underwent breast-conserving surgery and 81.8% had node-negative disease.
- All plans used a single-class RapidPlan volumetric modulated arc therapy workflow. Prescriptions were 50 Gy in 25 fractions, 40.05 Gy in 15 fractions or 26 Gy in five fractions, with simultaneous integrated boost and regional nodal irradiation when indicated.
- Treatment was delivered using two or three ipsilateral arcs with daily cone-beam computed tomography. Deep-inspiration breath hold was used when appropriate, and virtual bolus provided skin flash for intact-breast and postmastectomy plans.
- Among 349 patients receiving breast or chest-wall irradiation without regional nodes, median mean heart dose was 1.95 Gy with standard fractionation, 1.03 Gy with 15 fractions and 0.66 Gy with five fractions.
- Corresponding median ipsilateral lung mean doses were 7.7, 5.22 and 3.56 Gy. Mean contralateral breast and lung doses remained below 1 Gy in nearly all breast-only subgroups.
- With regional nodal irradiation, median mean heart doses were 1.56, 1.28 and 0.99 Gy across standard, hypofractionated and ultrahypofractionated schedules. Ipsilateral lung mean doses were 9.71, 7.15 and 3.64 Gy, respectively.
- Primary clinical target volume D95% reached at least 95% of prescription in 99% of patients. At least 90% of the prescribed dose covered 90% of all nodal volumes in nearly every case, including 91.7% of internal mammary-chain targets.
- No grade 3 or higher clinician-reported acute toxicity occurred. Grade 2 dermatitis affected 9%, grade 1 dermatitis 81%, and no radiotherapy-related pneumonitis was recorded; 83% reported no clinically significant fatigue.
CLINICAL TAKEAWAY
A carefully commissioned knowledge-based VMAT class solution can produce consistently strong breast and regional nodal plans without the excessive heart or lung exposure often attributed to VMAT. The study cannot establish superiority over tangential or hybrid techniques, and it provides no mature evidence on fibrosis, cardiac events, secondary malignancies or patient-reported outcomes.