Systematic reviews of chemotherapy and endocrine therapy in metastatic breast cancer

Metastatic breast cancer is incurable but often responsive to treatment. Th ere is little evidence-based consenus on when to use which treatments, in w hat combination and for how long. Systematic reviews were performed on 12 p rospectively defined, clinically relevant research questions to support the development of evidence-based clinical practice guidelines. A comprehensiv e search of Medline from 1966 to 1996 identifed over 1800 controlled trials . Eligibility and data extraction were performed independently by two blind ed reviewers. Trial results were summarised by ratios of median survivals ( RMS) and P-values for survival curve comparisons with meta-analysis by weig hted combination of these statistics. Sixty-live publications reporting 97 treatment comparisons were included. There was moderate evidence that more rather than fewer cycles of chemotherapy improved survival (RMS: 1.23, P-0. 01). The evidence did not support: higher rather than lower doses of chemot herapy (or of endocrine therapy); any one class of endocrine agent over all others; multiple endocrine agents over a single agent; or; combined chemot herapy and endocrine therapy over either single modality. Only six trials a ssessed quality of life revealing better quality of life with more rather t han fewer cycles of chemotherapy and with standard rather than lower doses of chemotherapy These systematic reviews reveal counterintuitive evidence u seful to everyday practice, in particular that more rather than fewer cycle s of chemotherapy lead to better quality of life and longer survival. (C) 2 000 Harcourt Publishers Ltd.