ASHBY: Accelerated Super-Hypofractionated Breast Brachytherapy

Inclusion criteria

• Female
• New diagnosis of ductal carcinoma in situ (DCIS) and/or invasive breast carcinoma per histologic evaluation
• Age 45-79 at diagnosis
• Previous lumpectomy with surgical margins histologically free of invasive tumor and DCIS as determined by the pathologist.
• T stage of Tis, T1, or T2.
• T2 tumors must be ≤3 cm in maximum diameter
• If the tumor is human epidermal growth factor receptor 2 (HER2)-positive, the patient must receive HER2-directed therapy.
• For patients with invasive breast cancer, an axillary staging procedure must be performed (either sentinel node biopsy alone or axillary dissection \[with a minimum of 6 axillary nodes removed\]) and the axillary node\[s\] must be pathologically negative.
• Note: N0(i+) is not an exclusion criterion.
• Note: Patients meeting all of the following criteria are not required to undergo the axillary staging procedure:
• ≥70 years of age
• estrogen receptor, Her2 = human epidermal growth factor receptor 2, PR = progesterone receptor negative (ER+PR+HER2-)
• G1-2
• Tumor ≤2 cm in size
• Agrees to comply with aromatase inhibitor recommendation
• Ability to understand and the willingness to sign a written informed consent document in English

Exclusion criteria

• Pregnant or breastfeeding
• Active collagen-vascular disease
• Paget's disease of the breast
• History of DCIS or invasive breast cancer prior to the current diagnosis
• Prior breast or thoracic radiation therapy (RT) for any condition
• Multicentric carcinoma (DCIS or invasive)
• Synchronous bilateral invasive or non-invasive breast cancer
• Surgical margins that cannot be microscopically assessed or that are positive
• Excision cavity that cannot be clearly delineated per the treating investigator
• Any of the dosimetric treatment criteria defined in Section 6.1 have not been met. Patients who become ineligible due to inability to meet dosimetric criteria should not receive treatment as - defined in this protocol and will come off the study. Any subsequent adjuvant radiation will be delivered at the discretion of the treating physician
• Medical, psychological, or social condition that, in the opinion of the investigator, may increase the patient's risk or limit the patient's adherence with study requirements