Pilot Study to Validate Metallic Markers for Image Guided Radiation Therapy for Breast Cancer Tx

Inclusion Criteria:

* Pathologically confirmed stage 0, I or II bilateral or unilateral breast cancer
* Any invasive adenocarcinoma or intraductal carcinoma
* Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2
* Surgical treatment with lumpectomy (partial mastectomy)
* Successful placement of intraparenchymal metallic markers at last breast surgery
* Pathologic tumor size \< 5.0 cm (Microscopic multifocality is allowed if total pathologic tumor size is within 5 cm)
* Axillary sampling (sentinel node or axillary dissection) performed for axillary nodal staging for all invasive cancers. No axillary sampling is required for ductal carcinoma in situ)
* Negative margins of excision.
* Radiation treatment to begin within 8 weeks after last surgery or last dose of chemotherapy
* Negative post-biopsy mammogram if presented with mammographically detected microcalcifications to ensure removal of suspicious calcifications
* History of prior cancers is allowed if patient is without evidence of disease at the time of study entry
* Ability to understand and the willingness to sign written informed consent document

Exclusion Criteria:

* Pregnant or breast feeding at time of study entry. Note: Radiation therapy is teratogenic. Women of child bearing potential must agree to use adequate contraception (abstinence, hormonal or barrier method of birth control) prior to and during study participation. Should a woman become pregnant, she should inform the treating physicians immediately.
* Prior in-field irradiation
* Stage III or IV breast cancer
* Inability to place intraparenchymal metallic markers due to excessive bleeding or other intraoperative complication so that the surgeon deems it inadvisable to place the marker
* Pathologic tumor size \>/= 5 cm
* Positive or unassessed margins of surgical resection
* Diffuse calcifications on mammogram pre- or post-operatively
* Positive or suspicious post-lumpectomy mammogram or breast magnetic resonance imaging (MRI)
* Multicentric carcinoma in more than one quadrant of the breast
* Non-epithelial breast malignancy; Paget's disease of the nipple
* Personal history of collagen vascular disease clinically judged to be a contraindication to radiation therapy
* Recurrent disease or prior history of ipsilateral breast cancer
* Psychiatric or addictive disorders that impair patient's voluntary ability to participate in informed consent or protocol procedures