Phase 2 Surgical Excision vs Neoadjuvant Radiotherapy+Delayed Surgical Excision of Ductal Carcinoma

Inclusion Criteria:

   - Core needle biopsy demonstrating DCIS (ductal carcinoma in situ) of non-palpable,
   image-detected breast abnormality

   - Signed and dated IRB-approved written informed consent

   - Mammographic or MRI non-mass lesion (calcifications, non-mass enhancement on MRI)
   measuring 4 cm or less in greatest dimension

   - Estrogen receptor positive or negative, progesterone receptor positive or negative
   DCIS; HER2 positive, negative or unknown DCIS is allowed.

   - Patients must have a biopsy marker placed within the tumor bed confirmed on post
   biopsy imaging and evidence of residual radiographic abnormality. The post-biopsy
   mammogram must be performed within 6 weeks of randomization date

   - Placement of Savi scout optical reflectance marker in tumor bed area as a wireless
   guide for surgery and for neoRT treatment planning is preferred but not required if
   anatomic landmarks are sufficient for radiation planning. If required, then placement
   occurs before treatment is initiated (surgery or neoRT), but not necessarily before
   randomization. If anatomic landmarks are used for arm 2, then needle or wireless
   devices are allowable for surgical preoperative targeting.

   - Planned lumpectomy. Mastectomy will be acceptable if lumpectomy fails by virtue of
   involved margins or size of lesion, or patient chooses this approach after
   randomization

   - Review of imaging studies by Radiation Oncologist to ascertain feasibility of PBI
   prior to randomization - based on their estimation that 30% or less of the breast
   volume will be encompassed in the radiation fields.

   - Patients who had a prior contralateral invasive or non-invasive (DCIS) cancer are
   eligible

   - ECOG performance status 0, 1, or 2 Protocol Version #9 19 March 18, 2021

   - Concurrent foci of atypia or lobular carcinoma in situ in the ipsilateral or
   contralateral breast are allowed

Exclusion Criteria:

   - Invasive carcinoma on core needle biopsy, including microinvasive carcinoma

   - Radiographic extent of DCIS >4.0 cm

   - Mass lesion on breast imaging or palpable tumor

   - No residual radiographic lesion after diagnostic percutaneous core needle biopsy

   - Prior history of ipsilateral invasive or noninvasive breast cancer

   - Pregnant or breastfeeding

   - Prior ipsilateral breast or chest irradiation

   - Multicentric or multifocal DCIS

   - Synchronous contralateral invasive or non-invasive breast cancer

   - Pagets' disease of the breast

   - Active collagen vascular disease

   - Positive axillary lymph nodes

   - Not meeting the described criteria for partial breast irradiation during initial
   clinical evaluation

   - Psychiatric or addictive disorders or other condition, that, in the opinion of the
   investigator, would preclude the patient form meeting the study requirements or
   interfere with the interpretation of study results

   - Endocrine therapy is not allowed prior to surgery unless continued for a contralateral
   cancer