RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Giving CT-guided accelerated radiation therapy before surgery may make the tumor smaller and reduce the amount of normal tissue that needs to be removed.

PURPOSE: This clinical trial is studying giving radiation therapy followed by surgery to see how well it works in treating patients with early-stage breast cancer.

OBJECTIVES:

• is to investigate the impact of a short fractionated schedule given preoperatively on local control, cosmesis and breast fibrosis.
• To further design optimal treatment strategies for individual breast cancer patients treated with breast-conserving therapy (BCT) on the basis of biological parameters, including the expression profile of the primary tumor, for both m-RNA as for micro-RNA, with first, a focus on radiotherapy responsiveness and second, on local recurrence rate, distant metastases and survival.
• proteomics will be studied in fine-needle aspiration samples. A classifier can be build (genomic or proteomic or any kind of molecular signature) to identify responders and non-responders
• quality of life

OUTLINE: Patients undergo image-guided preoperative accelerated partial-breast irradiation (PAPBI) 10 times over 12 days (10 x 4 Gy) and later in the study 5 times 6 Gy. Six weeks after completion of image-guided PAPBI, patients undergo surgery.

DISEASE CHARACTERISTICS:

• Diagnosis of unifocal cT1-2 (1-3 cm) pN0 M0 breast cancer
• Must have undergone a sentinel node procedure prior to irradiation

PATIENT CHARACTERISTICS:

• Not specified

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics