The clonogenic growth of advanced breast tumour lesions adds no value to that of established clinical prognosticators for survival.

We measured the clonogenic growth of 110 breast cancer samples obtained from 107 patients with advanced disease. We determined clonogenicity under conventional conditions and under conditions supplemented with growth factors and hormones that target breast tissue. After a median follow-up period of 6 years we analyzed our data to determine if and to what degree clonogenic growth of metastatic breast tumours was related to the survival of patients. We found that tumour clonogenicity and patient survival correlated weakly, particularly if compared to the strong correlations of patient survival with either performance status or tumour bulk. Furthermore, an association between tumour clonogenicity and patient survival was visible only for clonogenicity that was determined under hormone-supplemented conditions, and only for tumour lesions that formed 50 or more colonies per 500,000 cells cultured. Thus, we conclude that clonogenic growth of breast tumour samples incompletely reflects the tumour features that determine the course of advanced disease.