Accelerated Partial Breast Irradiation in One Fraction for Patients With Early-stage Disease and Favorable Histological Subtypes (Breast-1F).
This is a prospective, randomized, monocentric, non-inferiority interventional clinical study comparing an Accelerated Partial Breast Irradiation (APBI) for the surgical bed of early-stage breast cancer patients with favorable histological subtypes, using stereotactic radiotherapy in a single dose of 15.5 Gy with Simultaneous Integrated Boost (SIB) to 21 Gy (study treatment, delivered in a single fraction) versus multifractionated radiotherapy of 30 Gy in 5 fractions (standard treatment, delivered in 5 fractions).
• Histological diagnosis of breast cancer
• Patients aged ≥40 years
• Signed informed consent
• Stage pTis-T2, up to 3 cm in the greatest diameter
• Luminal A and Luminal B HER2-negative histological subtypes
• Negative surgical margins (≥ 0.2 cm)
• Negative lymph nodes at sentinel lymph node biopsy, or alternatively with imaging tests (Positron Emission Tomography (PET)/Computed Tomography (CT) and/or axillary ultrasound, and/or breast Magnetic Resonance Imaging (MRI) with and without contrast), or, in rare cases, where still performed, with axillary dissection
• Clinical M0 (PET/CT and/or bone scintigraphy and/or abdomen-pelvis CT with and without contrast in suspected patients), within the previous 3 months.
• Performance Status (PS) Eastern Cooperative Oncology Group (ECOG) ≤2
⁃ No prior thoracic radiotherapy
⁃ Fertile women using contraception methods initiated during oncological treatment.