RATIONALE: Diagnostic procedures, such as single-photon emission computed tomography and computed tomography lymphoscintigraphy, may help lower the dose of radiation therapy after surgery, and help prevent lymphedema.

PURPOSE: This clinical trial is studying single-photon emission computed tomography and computed tomography lymphoscintigraphy followed by intensity-modulated radiation therapy to see how well they work in treating patients who have undergone surgery for stage I or stage II breast cancer.

OBJECTIVES:

• To assess the feasibility of integrating Philips Precedence SPECT/CT® images with GE PET/CT Fusion software to reduce radiation dosimetry delivered to lymph nodes draining the arm in patients after surgery for stage I or II breast cancer.
• To examine the differences in radiation dosimetry in these patients using 3-D conformal radiotherapy with vs without the Philips Precedence SPECT/CT®.
• To compare reduction in lymph node radiation dosimetry in these patients using single photon emission computed tomography (SPECT) and computed tomography (CT) with 3-D conformal radiotherapy vs intensity-modulated radiotherapy.

OUTLINE: Patients receive filtered technetium Tc 99m sulfur colloid (TcSC) intradermally and undergo single photon emission computed tomography (SPECT) and computed tomography (CT) imaging at the time of TcSC and 2 hours after injection. Patients then undergo intensity-modulated radiotherapy of the whole breast, including the low axilla and lymph nodes identified by the Phillips Precedence SPECT/CT® at a dose determined by computer analysis of the imaging information.

Patients complete a lymphedema screening questionnaire at baseline and at 12 and 24 months after treatment.

DISEASE CHARACTERISTICS:

• Biopsy-proven primary invasive breast cancer, meeting one of the following criteria:

  • Stage I or II disease with negative sentinel or axillary node dissections
  • Stage II disease with micrometastases (defined as < 2.0 mm focus) in 1-2 lymph nodes and/or a single positive axillary node ≤ 1 cm with no extracapsular extension

• Completed all surgical intervention (e.g., lumpectomy, mastectomy)

• Planning adjuvant whole breast irradiation including the low axilla

• No bilateral or recurrent breast cancer

PATIENT CHARACTERISTICS:

• ECOG performance status 0-2
• Not pregnancy or nursing
• Negative pregnancy test
• Able to complete questionnaire(s) alone or with assistance
• No active infection
• No history of invasive cancer within the past 5 years, except basal cell or squamous cell skin cancers

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• No prior surgery or radiation to the ipsilateral breast or axilla
• No concurrent neoadjuvant chemotherapy or radiotherapy