DISEASE CHARACTERISTICS:

• Histologically confirmed stage I or IIA (T1 or T2, N0, M0) invasive breast carcinoma amenable to lumpectomy

  • Tumor must be less than 5 cm
  • No palpable nodes
  • No evidence of metastatic disease
  • Cytologic diagnosis suggestive of carcinoma from a fine-needle aspiration from a palpable or nonpalpable breast lesion and clinically suspicious for invasive breast carcinoma allowed
• No concurrent bilateral breast malignancies
• Diagnosis no more than 60 days prior to sentinel lymph node dissection (SLND)
• Sentinel node must have been identified and found to contain metastatic disease
• No matted lymph nodes or gross extranodal disease
• No more than 2 positive sentinel nodes
• No clinically or radiologically identified multifocal disease not amenable to a single lumpectomy

• Hormone receptor status:

  • Estrogen receptor positive or negative

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Sex:

• Female

Menopausal status:

• Not specified

Performance status:

• ECOG (Zubrod) 0-2

Life expectancy:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Not specified

Renal:

• Not specified

Other:

• Must not be considered a poor surgical risk due to any other nonmalignant systemic disease
• No other prior malignancies within the past 5 years except successfully treated basal cell or squamous cell skin cancer or surgically treated carcinoma in situ of the cervix or lobular carcinoma in situ of the ipsilateral or contralateral breast
• All prior malignancies must have been curatively treated and risk of recurrence must be low
• Not pregnant or nursing
• Negative pregnancy test
• No other medical condition contraindicating axillary lymph node dissection or postoperative breast radiotherapy

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No prior chemotherapy for this breast cancer

Endocrine therapy:

• No prior estrogen receptor antagonist (i.e., tamoxifen) or selective estrogen receptor modulators therapy (i.e., raloxifene) for this breast cancer

Radiotherapy:

• Not specified

Surgery:

• Prior breast-conserving therapy (i.e., segmental mastectomy) allowed if no more than 60 days prior to SLND

• No pre-pectoral breast implant

  • Subpectoral implant allowed
• No prior ipsilateral axillary surgery (e.g., excisional biopsy of the lymph nodes or treatment of hidradenitis)