Real-Time Assessment Of Breast Cancer Lumpectomy Specimen Margins With Nonlinear Microscopy

Inclusion Criteria: * Patient scheduled to undergo lumpectomy for breast cancer at BIDMC. * Core needle biopsy revealing invasive breast cancer or DCIS. * Female. * Minimum age of 21 years. * Eligible for breast conserving surgery, lumpectomy and radiation. * Estrogen receptor positive (ER+) on core needle biopsy, or if estrogen receptor negative (ER-), have evaluable estrogen receptor status with positive internal control on core biopsy. * Progesterone receptor positive (PR+) on core needle biopsy if biopsy indicates invasive cancer, or if progesterone receptor negative (PR-) on biopsy indicating invasive cancer, have evaluable progesterone receptor status with positive internal control on core biopsy. * HER2 IHC and/or FISH ordered on core biopsy, if biopsy indicates invasive cancer. * Oncotype DX or other genetic assay performed on core biopsy or not requested. * Ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: * Contraindicated for radiation therapy. * Pregnancy. (Pregnant women will be excluded from this study because radiation therapy is contraindicated during pregnancy.) * Current invasive cancer or DCIS at the site of a previous surgery. * Any systemic neoadjuvant (or preoperative) therapy between the core biopsy and lumpectomy. * Involvement in another therapeutic trial for breast cancer at Dana Farber or elsewhere. * Risk of poor cosmetic outcome after initial lumpectomy and possible additional excision, as assessed by a study surgeon. * Recommendation for mastectomy based on radiology. * Patients that have complex DCIS as indicated on radiology, which would require excising a large tissue volume. * No or equivocal ER, PR or HER2 testing performed prior to surgery if biopsy indicates invasive cancer. * No or equivocal ER testing performed prior to surgery if biopsy indicates ductal carcinoma in situ.