Randomized,non-blinded,multi-center study in patients with metastatic breast cancer.Patients will be treated with docetaxel or docetaxel-gemcitabine.

Aim of the study is to assess the optimal dosage and safety in this setting.

Inclusion Criteria:

• histologically verified diagnosis of breast carcinoma, at first diagnosis
• restricted previous adjuvant chemotherapy (completed >6 months prior the study)
• measurable and/or non-measurable disease
• previous radiotherapy is allowed if:terminated at least 10 days prior the sudy therapy, at least one target lesion for evaluation of tumor response has not been irradiated
• performance status 0-2 (WHO, Zubrod)
• adequate bone marrow reserve defined
• adequate liver / renal functions defined

Exclusion Criteria:

• any prior systematic chemotherapy for metastatic breast cancer

• expected survival time less than 12 weeks

• past or current history of malignant neoplasm other than breast carcinoma

  • except for cured non-melanoma skin cancer or curatively treated in situ carcinoma of the cervix uteri

• known brain metastases/leptomeningeal involvement

• active uncontrolled infection

• symptomatic peripheral neuropathy > grade 2 according to NCI

• patients whose lesions are assessable only by radionuclide scan or patients with sclerotic bone lesions as the only site of disease

• concomitant illness that is contraindication to the use of corticosteroids

• other concomitant serious illness or medical condition, which may worsen due to the treatment

Anonymized individual patient level data will be provided in a secure access environment upon approval of a research proposal and a signed data sharing agreement.

Data are available 6 months after the primary publication and approval of the indication studied in the US and EU, whichever is later. Data will be indefinitely available for requesting.

A research proposal must be approved by an independent review panel and researchers must sign a data sharing agreement.