S0500 Treatment Decision Making Based on Blood Levels of Tumor Cells for Metastatic Breast Cancer Treated With Chemo

DISEASE CHARACTERISTICS:

* Histologically confirmed breast cancer

  * Clinical evidence of metastatic disease (stage IV disease)
  * Newly metastatic disease OR progressive metastatic disease while on hormonal therapy
* Meets 1 of the following criteria:

  * Measurable disease
  * Bone-only disease\* NOTE: \*Patients with nonmeasurable disease that does not include bone are not eligible
* HER-2 status determined by immunohistochemistry (IHC) or fluorescent in situ hybridization (FISH) assay

  * HER-2 positivity is defined as IHC 3+ or FISH+
  * If IHC is indeterminate (2+), FISH must be performed to classify disease
* Planning to undergo first-line chemotherapy for metastatic disease
* Patients with brain metastases must have stable disease for \> 90 days after completion of prior radiotherapy to the brain
* No leptomeningeal disease
* Hormone receptor status not specified

PATIENT CHARACTERISTICS:

* Female
* Menopausal status not specified
* Zubrod performance status 0-2
* Not pregnant or nursing
* Negative pregnancy test
* No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or stage I or II cancer currently in complete remission

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* Prior hormonal therapy, bisphosphonate therapy, trastuzumab (Herceptin®), and/or bevacizumab for metastatic disease allowed

  * Any number of exogenous hormonal therapies for metastatic disease and/or as adjuvant therapy allowed
* At least 1 year since prior adjuvant chemotherapy
* At least 2 weeks since prior minor surgery and recovered
* At least 4 weeks since prior major surgery and recovered
* No prior chemotherapy for metastatic disease
* Concurrent hormonal therapy and/or bisphosphonate therapy allowed
* Concurrent trastuzumab and/or bevacizumab allowed