Estrogen and Progesterone Receptor Status in Primary Breast Cancer – A Study of 11,273 Patients from the Year 1990 to 2002

The aim of this study was to gain insight of the breast cancer hormone receptor status of our patients, its stratification according to age as well as its changes during the period of 13 years. 11,273 patients with primary breast cancer from several towns in Croatia were included in this study. Patients’ tumour specimens were collected from 1990 to 2002 and were analysed on estrogen (ER) and progesterone (PR) receptors in the Laboratory of the Department of Medical Oncology, University Hospital Centre Zagreb. More than half of our breast cancer patients had ER positive tumours (54.3%). We observed ER+ tumours increased with age continuously, with highest percentage in the age group of 70 to 79 years (68.1%). Similarly, proportion of PR+ tumours was higher in the older age groups, being the highest between 40 and 49 years (55.9%). During 13 years of the study, the increase in frequency and proportion of ER+ tumours was observed (from 52% in 1990 to 62% in 2002) and decrease of PR+ tumours (56% to 53%). We confirm previous findings that the risk of hormone dependent breast cancer increases with aging. Risk of ER+ breast cancer increased for 10% from 1990 to 2002 and PR+ tumours decreased for 3.5% in the same period