This study investigates the safety and efficacy of hypofractionated radiotherapy (HFRT) versus conventional fractionated radiotherapy (CFRT) in breast cancer patients undergoing total mastectomy with prosthetic reconstruction.

Study Design Population: Patients with high-risk breast cancer after mastectomy and immediate implant reconstruction.

Intervention:

HFRT Arm: 43.5 Gy in 15 fractions (2.9 Gy/fraction, 3 weeks). Control Arm: CFRT (50 Gy in 25 fractions, 2 Gy/fraction, 5 weeks). Endpoints Primary: Reconstruction failure rate (e.g., implant removal, capsular contracture)

Inclusion Criteria:

• Female, aged 18-75 years
• Karnofsky Performance Status ≥60
• Histopathologically confirmed invasive breast adenocarcinoma
• Total mastectomy [with or without nipple-areolar complex preservation] + axillary dissection/sentinel lymph node biopsy + implant/expander placement R0 resection with negative margins
• pT3 or N2-3 disease; or pT1-2N1
• No distant metastasis
• Completed standard neoadjuvant/adjuvant chemotherapy cycles
• ≤8 weeks post-chemotherapy or ≤12 weeks post-surgery if no chemotherapy
• Signed informed consent

Exclusion Criteria:

• Prior radiotherapy to chest wall or nodal regions
• Pregnancy or lactation
• T4 stage disease
• Autologous breast reconstruction of the irradiated breast
• Pre-radiotherapy local/regional/distant metastasis
• Grade ≥3 implant-related adverse events irreversible before radiotherapy
• Bilateral breast cancer requiring bilateral radiotherapy
• Concurrent/secondary malignancy with disease-free interval <5 years [except non-melanoma skin cancer, papillary/follicular thyroid cancer, or cervical carcinoma in situ]
• Active collagen vascular disease, e.g., SLE, scleroderma
• Uncontrolled comorbidities: acute cardiovascular disease, substance abuse, or psychiatric disorders

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