Chemotherapy alone versus endocrine therapy alone for metastatic breast cancer.

BACKGROUND

Both chemotherapy and endocrine therapy can be used as treatments for metastatic breast cancer.

OBJECTIVES

To review the evidence and determine whether chemotherapy or endocrine therapy has the most beneficial effect on treatment outcomes (survival, response rate, toxicity and quality of life).

SEARCH STRATEGY

The specialised register maintained by the Editorial Base of the Cochrane Breast Cancer Group was searched on 16th September 2002 using the codes for "advanced breast cancer", "chemotherapy" and "endocrine therapy". Details of the search strategy applied by the Group to create the register, and the procedure used to code references, are described in the Group's module on the Cochrane Library.

SELECTION CRITERIA

Randomised trials comparing the effects of chemotherapy alone with endocrine therapy alone on pre-specified endpoints in metastatic breast cancer.

DATA COLLECTION AND ANALYSIS

Data were collected from published trials. Hazard ratios were derived for survival analysis and a fixed effect model was used for meta-analysis. Response rates were analysed as dichotomous variables. Toxicity and quality of life data were extracted where present.

MAIN RESULTS

The primary analysis of overall effect using hazard ratios derived from published survival curves involved six trials (692 women). There was no significant difference seen (HR=0.94, 95%CI 0.79-1.12, p=0.5). A test for heterogeneity was p=0.1. A pooled estimate of reported response rates in eight trials involving 817 women shows a significant advantage for chemotherapy over endocrine therapy with RR=1.25 (1.01-1.54, p=0.04). However the two largest trials showed trends in opposite directions, and a test for heterogeneity was p=0.0018. There was little information available on toxicity and quality of life. Six of the seven fully published trials commented on increased toxicity with chemotherapy, mentioning nausea, vomiting and alopecia. Three of the seven mentioned aspects of quality of life, with differing results. Only one trial formally measured quality of life, concluding that it was better with chemotherapy.

REVIEWER'S CONCLUSIONS: In women with metastatic breast cancer and where hormone receptors are present, a policy of treating first with endocrine therapy rather than chemotherapy is recommended except in the presence of rapidly progressive disease.