Single Pre-Operative Radiation Therapy - With Delayed Surgery for Low Risk Breast Cancer

Inclusion criteria

• Female aged 65 years or older
• World Health Organization (WHO) performance status 0-2
• Invasive ductal carcinoma proven by biopsy done ≤ 12 weeks from treatment start
• Unifocal disease on preoperative staging ultrasound done ≤ 12 weeks from treatment start
• Tumors less than 2cm clinically on physical exam, as well as on breast ultrasound
• No clinical evidence of nodal disease (i.e. cN0), on physical examination done ≤ 12 weeks from treatment start, as well as on breast ultrasound
• Estrogen receptor status (ER) positive on biopsy
• Her2 negative on biopsy
• Grade 1 or 2 on biopsy
• Planned surgery is a partial mastectomy with sentinel lymph node biopsy
• Localisation markers placed before treatment

Exclusion criteria

• Age less than 65 years
• A known deleterious mutation in BRCA 1 and/or BRCA 2
• Clinical tumor size > 2.0 cm in greatest diameter on staging ultrasound
• Tumor histology limited to lobular carcinoma only
• Clinically positive axillary nodes (cN+)
• Lymphovascular invasion on biopsy
• Pure ductal or lobular carcinoma in situ on biopsy
• Extensive intraductal component on biopsy
• Neoadjuvant hormonal manipulation or chemotherapy
• Prior history of cancer (Patients with prior or concurrent basal cell or squamous cell skin cancers are eligible for the trial)
• More than one primary tumor in different quadrants of the same breast
• Diffuse microcalcifications on mammography
• Paget's disease of the nipple
• Previous irradiation to the ipsilateral breast
• Presence of an ipsilateral breast implant or pacemaker
• Serious non-malignant disease (e.g. cardiovascular, pulmonary, systemic lupus erythematosus (SLE), scleroderma) which would preclude definitive radiation treatment
• Estrogen receptor status (ER) not known
• Currently pregnant or lactating
• Psychiatric or addictive disorders which would preclude obtaining informed consent or adherence to protocol
• Geographic inaccessibility for follow-up
• Lack of preoperative staging with breast and axillary ultrasound
• Inability to adequately plan the patient for the experimental technique