Negative (clean) margins will be defined as no tumor seen in the surrounding tissue by pathological evaluation following the procedure. Negative margins will be analyzed as the proportion of patients with negative margins relative to all patients who participated in the study. Negative margins (as determined by biopsies of surrounding tissue upon pathological assessment) observed in ≥ 90% of patients who participate in the study is the threshold for this feasibility outcome.

Local recurrence will be defined as evidence of invasive or in situ breast cancer in the ipsilateral breast or chest wall. Patients who develop clinical evidence of tumor recurrence in the remainder of the breast or chest wall will be recommended to have a biopsy of the suspicious lesion to confirm the diagnosis. If a biopsy is not performed for any reason, an imaging designation of BIRADS 4 and 5 will be considered evidence of disease recurrence. Given the challenges of reliably defining local recurrence vs. new primary, all recurrences in the ipsilateral breast will be considered in the analysis of local recurrence. Local recurrence will be evaluated in patients for 5 years after study procedure using Kaplan-Meier methods.

Patient satisfaction related to the time necessary to complete the procedure will be evaluated via administration of a questionnaire. Patients will be asked to rate satisfaction of the time needed based on a 5-point scale ranging from 1 ("Very Dissatisfied") to 5 ("Very Satisfied"), such that higher scores are indicative of better satisfaction with the time needed to complete the procedure.

Pain associated with the procedure will be evaluated via administration of a questionnaire. Patients will be asked to rate pain associated with the procedure based on a 6-point scale ranging from 1 ("No pain") to 5 ("Worst pain possible"), such that lower scores are indicative of less pain severity in association with the procedure.

Symptom severity associated with the procedure will be evaluated via administration of a questionnaire. Patients will be asked to rate the severity of their symptoms using a 4-point scale ranging from 1 ("Mild") to 4 ("Very Severe"), such that lower scores are indicative of less symptom severity associated with the procedure.

Patient satisfaction with breasts prior to treatment will be evaluated using Version 2.0 of the Breast-Q 'Satisfaction with Breasts' module. The preoperative Breast-Q module consists of 4 questions which asks patients to describe how satisfied/dissatisfied they have been over the past week with their breasts. The 4 responses are rated using a 4-point scale ranging from 1 ("Very Dissatisfied") to 4 ("Very Satisfied"), yielding a raw sum score of 4-16. Raw Breast-Q sum scores are then converted using a validated "Equivalent Rasch Transformed Score" table ranging from 0-100 such that higher Rasch scores are indicative of a better outcome. If missing data comprises <50% of the scale's items, the mean of the missing items is inserted into the table.

Patient satisfaction with breasts and breast cancer treatment prior following the procedure will be evaluated using Version 2.0 of the Breast-Q breast cancer treatment (BCT) module. This Breast-Q module consists of 11 questions which ask patients to describe how satisfied/dissatisfied they have been over the past week with respect to their breasts and breast cancer treatment. The 11 responses are rated using a 4-point scale ranging from 1 ("Very Dissatisfied") to 4 ("Very Satisfied"), yielding an overall sum score of 11-44. Raw Breast-Q sum scores are then converted using a validated "Equivalent Rasch Transformed Score" table ranging from 0-100 such that higher Rasch scores are indicative of a better outcome. If missing data comprises <50% of the scale's items, the mean of the missing items is inserted into the table.