Question: What is the role of vinorelbine as second-line chemotherapy following anthracycline failure for women with stage IV breast cancer? Perspective: Evidence was selected and reviewed by one member of the Provincial Breast Cancer Disease Site Group (DSG) of the Cancer Care Ontario Program in Evidence-based Care. Drafts of this overview were reviewed, discussed, and approved by the Breast Cancer DSG, which comprises surgeons, medical oncologists, radiation oncologists, epidemiologists, a pathologist, a medical sociologist, and community representatives. Methodology: Sources of Evidence: Relevant evidence was identified by a systematic search of the MEDLINE and CANCERLIT databases (using 'breast neoplasms' as a MeSH term and 'vinorelbine' and 'navelbine' as text words), the Cochrane Library, conference proceedings, and reference lists. Unpublished evidence was solicited from Glaxo-Wellcome. Patient Population: Women with stage IV breast cancer who have failed first-line chemotherapy for metastatic disease. Outcomes of Interest: Survival, quality of life, and functional status were the primary outcomes of interest. Response rate and response duration were also considered. Results: Search Results. One randomised controlled trial comparing vinorelbine with melphalan as second- or third-line chemotherapy in stage IV (metastatic) breast cancer and eight prospective case series (phase II studies) where vinorelbine was used as a single agent met the eligibility criteria for this evidence summary. Data from adverse effects came from an overview of the toxicity data from three North American studies of vinorelbine for metastatic breast cancer. Benefits: The randomised controlled trial comparing vinorelbine with melphalan showed vinorelbine to be superior with respect to survival rate (median survival = 35 weeks with vinorelbine vs. 31 weeks with melphalan, p = 0.034). Greater physical functioning was observed in vinorelbine-treated patients than in melphalan-treated patients, with equivalent results for symptom status, role function, and global quality of life. Response rate was the only relevant outcome available from the phase II trials. For vinorelbine as second-line or greater therapy, the pooled response rate was 24% (95% confidence interval [CI]: 20-28%); in anthracycline-resistant disease, the pooled objective response rate was 19% (95% CI: 14-24%). Harms: The majority of adverse events observed were haematologic: neutropenia (96% of patients in three studies), febrile neutropenia (9%), and anaemia (87%). Other adverse events included nausea (50%), vomiting (23%), diarrhoea (20%), constipation (38%), and alopecia (12%). Peripheral neuropathy was observed in 31% of patients, but it was usually grade 1 or 2 and reversible. Approximately 20% of patients reported pain at the site of infusion. One phase II trial showed a decline in physical and role functions, with a corresponding increase in symptom distress during the first cycle of treatment.