To de-escalate radiation therapy in women with breast cancer.
Female patient with a new histological diagnosis of clinical T1-3 N0 breast cancer (any tumour sub-type).
Negative lymph node involvement at initial presentation, documented by imaging (US or MRI), fine needle aspiration (FNA) or core needle biopsy.
Treated with a minimum of 8 weeks NAC, with patients with Her2+ disease receiving targeted anti-Her2+ therapy.
Marker clip placed in the tumour bed prior to or during neoadjuvant chemotherapy when the tumour can still be identified.
Age less than 50 years.
Inflammatory breast cancer or breast cancer invading the skin or chest wall (T4 disease).
Multicentric disease (i.e., breast cancer involving more than one quadrant in the same breast).
Prior history of ipsilateral or contralateral in-situ or invasive breast cancer. Patients with a history of lobular carcinoma in-situ (LCIS) are ineligible.
Ontario Clinical Oncology Group (OCOG)
Lead sponsor
Canadian Institutes of Health Research (CIHR)
Collaborator
Hamilton Health Sciences Corporation
Collaborator