It is well established that a woman's reproductive history influences her risk of breast cancer.
We examined whether the effect of reproductive history was similar for different sub-types of breast cancer.
The study was based on a population-based cohort of 1.5 million Danish women born between 1935 and 1978, with individual information on births.
Between 1978 and 1994,10,790 incident cases of breast cancer were identified in a nationwide cancer registry, including detailed information on receptor status, histology, laterality and location of the tumour.
Overall, the incidence of breast cancer was 13% lower in parous compared with nulliparous women.
This reduction was significantly stronger for mucinous than for ductal carcinomas and for tumours located centrally than for those non-central in the breast.
Overall, the incidence in parous women increased by 10% by each 5-year postponement of their first birth.
For the incidence of lobular carcinomas this increase was significantly stronger, and for mucinous carcinomas it tended to be stronger than for ductal carcinomas.
For the incidence of centrally located tumours the increase was stronger than for non-centrally located tumours.
On average, there was a 10% decrease in breast-cancer risk by each additional birth.
This decrease was seen in most sub-types, but not for lobular carcinomas of for centrally located tumours. (...)
Mots-clés Pascal : Carcinome, Glande mammaire, Facteur risque, Epidémiologie, Reproduction, Parité, Oestrogène, Récepteur hormonal, Type histologique, Histopathologie, Latéralité, Localisation, Etude cohorte, Danemark, Europe, Homme, Tumeur maligne, Glande mammaire pathologie, Hormone stéroïde sexuelle, Hormone ovarienne, Anatomopathologie
Mots-clés Pascal anglais : Carcinoma, Mammary gland, Risk factor, Epidemiology, Reproduction, Parity, Estrogen, Hormonal receptor, Histological type, Histopathology, Laterality, Localization, Cohort study, Denmark, Europe, Human, Malignant tumor, Mammary gland diseases, Sex steroid hormone, Ovarian hormone, Pathology
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0170161
Code Inist : 002B20E02. Création : 16/11/1999.