Biomarker prediction of clinical outcome in operable breast cancer patients treated with tamoxifen

The predictivity of tumour size, oestrogen (ER) and progesterone (PgR) receptors, 3H-thymidine labelling index (TLI), c-erbB-2 and p27kip1 expression on clinical outcome was analysed on a consecutive series of 118 postmenopausal patients with ER-positive, node-positive tumours. All patients were treated with surgery ± radiotherapy and adjuvant tamoxifen (30mg/day) for at least 2 years. TLI, ER, c-erbB-2 and p27kip1 were generally unrelated to each other. PgR was directly related to ER and inversely to c-erbB-2. Tumour size was inversely related to both c-erbB-2 and p27kip1 expression. At a median follow-up of 75 months, 5-year relapse-free survival was significantly lower for patients with very rapidly proliferating (HR=2.61, 95% CI=1.34–5.08), PgR negative (HR=2.76, 95% CI=1.43–5.33) or relatively low ER content (HR=2.20, 95% CI=1.14–4.25) tumours than for patients with tumours expressing the opposite biological profiles. Overall survival was also significantly different as a function of TLI (HR=3.47, 95% CI=1.52–7.93) and PgR (HR=2.27, 95% CI=1.00–5.15). TLI and PgR maintained an independent relevance in multivariate analysis and together were capable of identifying subgroups of patients at significantly different risk of relapse and death.