A multicenter, observational, non-post-marketing (non-PMS), ambispective (retrospective and prospective from the registry opening) study which will enroll patients with breast cancer in any of these three situations:~Patients with gestational breast cancer, defined as breast cancer diagnosed during pregnancy, breastfeeding or up to a year after delivery.~Patients who become pregnant after a breast cancer diagnosis.~Patients with breast cancer who have followed any fertility preservation technique prior to the start of breast cancer treatment.~It is estimated a minimum recruitment period of approximately 3 years from the study activation. The study will remain open as long as possible in order to collect as much information as possible. GEICAM will actively search for funding for this.~Patients may also be concurrently enrolled in an interventional clinical trial. This observational registry study of pregnancy and breast cancer that collects significant data obtained from standard clinical practice, regarding the clinical characteristics of patients with breast cancer in any of the three situations described above. These data will allow the performance of both descriptive and exploratory analyses in order to evaluate the associations between different breast cancer subtypes and risk factors observed.~Finally, this study will collect high quality molecular data derived from the analysis of biological samples (paraffin-embedded tumor and peripheral blood samples) to reach a better understanding of the biological mechanisms involved in breast cancer in relation to pregnancy.~No treatment regimen will be protocol specified. This is an observational study in which clinical decisions concerning the optimum management strategy for a particular patient are taken independently of and/or prior to, any decision by the physician to invite a patient to participate in the study. The treating physician will make all treatment decisions according to his/her regular clinical practice independent of this study.
An ambispective observational registry study of pregnancy and breast cancer