Breast cancer patients at Sentara RMH Hahn Cancer Center who are treated with accelerated partial breast irradiation will be monitored over a period of 10 years. From this group of patients, local and regional recurrence rates will be determined. Patients in the registry will also take part in assessments of cosmesis and quality of life.

Studies have shown that giving radiation therapy to the breast after lumpectomy helps keep cancer from coming back in the breast. The purpose of this study is to see if partial breast irradiation (PBI) at SRMH Hahn Cancer Center is as good as partial breast irradiation performed in other centers in the United States in keeping cancer from coming back in the breast. Whole breast irradiation (WBI) is a standard treatment after a lumpectomy. WBI is radiation therapy given 5 days a week for 5 to 7 weeks to the whole breast. PBI is a new method of delivering radiation only to the area of the breast where the cancer was removed. PBI is given 2 times a day for 5 days. PBI may be given over a period of 5 to 10 days. This newer treatment is currently being compared with WBI in a randomized trial. Thus far, patients at low risk for cancer recurrence who have been treated with PBI have had excellent outcomes at 5 years post-treatment, but we will not know for sure if PBI is as good as WBI until the results of the randomized trial are available. However, PBI is commonly being offered outside of clinical trials in many community hospitals throughout the country. As radiation oncologists at Sentara RMH Hahn Cancer Center, we wanted to offer patients in our community the same opportunity to have this treatment, but also wanted to ensure close follow-up of all patients treated with this method, to be sure our results are similar to those of patients reported in our professional literature. There are two different methods of PBI that are being used at SRMH Hahn Cancer Center: Balloon brachytherapy and 3-D conformal external beam irradiation. This study will learn about the good and bad effects of radiation therapy. The study also will learn about the feelings women have about how their breast looks after surgery and radiation therapy.

Inclusion Criteria:

• The patient must consent to be in the study and must have signed an approved consent form approved by Sentara RMH Medical Center's IRB.
• Patients must be >/= 50 years or postmenopausal.
• The patient must have stage 0 or 1 breast cancer.
• On histological examination, the tumor must be DCIS or invasive non- lobular carcinoma of the breast.
• Surgical treatment of the breast must have lumpectomy. The margins of the resected specimen must be histologically free of tumor (DCIS and in- vasive) by 2 mm or more. Reexcision of surgical margins is permitted.
• Gross disease must be unifocal with pathologic (invasive and/or DCIS) tumor size 2 cm or less. Mucinous or tubular histologies maximum size may be up to 3 cm.
• Patients with invasive breast cancer are required to have axillary staging which can include sentinel node biopsy alone (if sentinel node is negative), sentinel node biopsy followed by axillary dissection or sampling with a minimum total of 6 axillary nodes including the sentinel nodes (if sentinel node is positive), or axillary dissection alone (with a minimum of 6 axillary nodes.) (Axillary staging is not required for patients with DCIS).
• The patient must begin treatment within 9 weeks following the last surgery for breast cancer (lumpectomy, re-excision of margins, or axillary staging procedure).
• Patients must have an estrogen receptor (ER) and progesterone receptor (PR) analysis performed on the primary tumor prior to enrollment.
• The target lumpectomy cavity must be clearly delineated and the ratio of target lumpectomy cavity/whole breast reference volume must be \

Women who satisfy all of the eligibility conditions are the only patients who will be eligible for this study.