To compare maintenance therapy to observation in metastatic breast cancer patients responding (or stabilized) after 1st-line chemotherapy. Main endpoint is disease-free survival. Secondary endpoints are overall survival and tolerance. A total of 200 patients will be included.

Inclusion Criteria:

• metastatic breast cancer
• objective response or stabilisation after 6 to 8 cycle of a first line chemotherapy
• time period between the end of chemotherapy and randomization < 4 weeks
• age over 18 years
• Performance status (OMS) < 2.
• Life expectancy > 3 months
• Biological criteria before randomization: Neutrophiles > 1.5 x 109 G/L; Pl. > 100 x 109 G/L; Hb > 10 g/dl; Creatininemia < 1,5 UNL; Bili. < 2 UNL; Transaminases < 2,5 UNL; Alcalines Phosphatases < 2,5 UNL
• Signed written informed consent

Exclusion Criteria:

• Metastatic breast cancer having received more than one chemotherapy line.
• Tumor progression under chemotherapy
• Free interval between primary tumor and metastases > 5 years, with estrogen receptors and without visceral metastases
• Free interval between primary tumor and metastases < 18 months after adjuvant chemotherapy if first lime chemotherapy only led to a tumor stabilization
• Concomitant hormonotherapy
• Other cancer
• Symptomatic brain metastases
• Any uncontrolled severe disease except breast cancer (especially cardiac failure with LVEF < 50% or coronary insufficiency
• Psychiatric disorder
• Other concomitant trial
• Male patient
• Pregnancy and breast-feeding (effective contraception is mandatory in the case of women of child-bearing potential)
• History of high dose chemotherapy with bone marrow transplantation