TNT is a phase III, multi centre, randomised trial of carboplatin versus docetaxel in women with ER-, PgR- and HER2- metastatic or recurrent locally advanced breast cancer. Patients will be randomised (1:1) to carboplatin or docetaxel and will cross over to the alternative treatment (docetaxel (if randomised to carboplatin) or carboplatin (if randomised to docetaxel)) on progression. Trial Treatment: Group A: Carboplatin AUC 6, q 3 weeks for 6 cycles (18 weeks) Group B: Docetaxel 100mg/m2, q 3 weeks for 6 cycles (18 weeks) On evidence of disease progression, patients will cross over to the alternative treatment.