RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Drugs used in chemotherapy, such as cyclophosphamide and doxorubicin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving radiation therapy together with cyclophosphamide and doxorubicin after surgery may kill any tumor cells that remain.

PURPOSE: This phase I/II trial is studying the side effects of radiation therapy when given together with cyclophosphamide and doxorubicin and to see how well they work in treating women with stage I or stage II breast cancer who have undergone surgery.

OBJECTIVES:

• Assess the potential acute and late skin and subcutaneous toxicities in women with resected stage I or II breast cancer treated with partial breast irradiation (PBI) and concurrent cyclophosphamide/doxorubicin (AC) chemotherapy.
• Assess the cosmetic effects of partial breast irradiation/chemotherapy (PBIC) in these patients.
• Assess the local control rate in patients treated with this regimen.

OUTLINE: Patients undergo partial breast radiotherapy once daily, 5 days a week, for 3 weeks. Patients also receive doxorubicin IV over 15 minutes and cyclophosphamide IV over 30 minutes on day 1. Treatment with doxorubicin and cyclophosphamide repeats every 2 weeks for up to 4 courses in the absence of disease progression or unacceptable toxicity.

After completion of study treatment, patients are followed periodically for approximately 10 years.

PROJECTED ACCRUAL: A total of 42 patients will be accrued for this study.

DISEASE CHARACTERISTICS:

• Histologically confirmed adenocarcinoma of the breast by routine hematoxylin and eosin (H&E) staining

  • Primary tumor ≤ 4 cm and 0-3 positive axillary lymph nodes (pathologic T1-2, pathologic N0-N1, M0)

    • Patients with lymph nodes positive only by cytokeratin staining (i.e., H&E negative) are eligible

• No squamous cell carcinoma or sarcoma of the breast

• Patients must have undergone a segmental mastectomy (SM) with a level I and ll axillary dissection or sentinel lymph node biopsy within the past 14 weeks

  • Surgical margins at the time of SM must be negative (> 3 mm) for both invasive carcinoma and for non-invasive ductal carcinoma

• No active local-regional disease

• Hormone receptor status not specified

PATIENT CHARACTERISTICS:

• ECOG performance status 0-1
• Sex: female
• Menopausal status not specified
• Not pregnant
• Negative pregnancy test
• Fertile patients must use effective non-hormonal contraception
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix
• No other serious or poorly controlled medical or psychiatric condition that could be exacerbated by, or complicate compliance with study treatment

PRIOR CONCURRENT THERAPY:

• No prior radiation therapy to the breast

• No prior trastuzumab (Herceptin ®)

• No other concurrent chemotherapy

• No concurrent hormonal therapy except the following:

  • Steroids given for adrenal failure
  • Hormones administered for non-disease-related conditions (e.g., insulin for diabetes, synthroid for hypothyroidism)
  • Intermittent dexamethasone as an antiemetic or premedication

Weekly then monthly then annually for up to 5 years.