Single-fraction APBI for Early-stage Breast Cancer With Favorable Histological Subtypes (Breast-1F)
Accelerated Partial Breast Irradiation in One Fraction for Patients With Early-stage Disease and Favorable Histological Subtypes (Breast-1F).
IRCCS San Raffaele
311 participants
Jul 25, 2025
INTERVENTIONAL
Conditions
Summary
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).
Eligibility
Inclusion Criteria11
- 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.
Exclusion Criteria17
- Patients aged \< 40 years
- Tumors \> 3 cm
- Multicentric tumors
- Positive or close surgical margins (\<0.2 cm)
- Lobular carcinoma
- Negative hormone receptors
- HER2-positive
- BReast CAncer (BRCA) genes BRCA1 and/or BRCA2 positive (only if known)
- Severe systemic diseases
- Psychiatric or other disorders that may prevent the patient from signing informed consent
- Previous invasive cancer, except for skin cancer (excluding melanoma) unless the patient has been disease-free for at least 3 years (e.g., carcinoma in situ of the oral cavity or bladder)
- Collagen or autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, scleroderma, Sjogren's syndrome)
- Lymph node disease (N1)
- Evidence of distant metastasis (M1)
- Contraindication to systemic treatment
- Pregnant women
- Non-compliance with the dose limits established in the treatment plan
Interventions
Experimental arm (arm 1-single-fraction APBI) patients will be treated to a total dose (TD) of 15.5 Gy to the PTV with a simultaneous integrated boost (SIB) to a TD of 21 Gy to the tumor bed, while arm 2-five-fractions APBI patients with 30 Gy/ 5 fractions to PTV.
Locations(1)
View Full Details on ClinicalTrials.gov
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NCT06946238