Editing Breast cancer (section)

=== '''Un-modifiable''' ===

** Increasing age
*** Rare in women <20yo
*** Steadily increases with age, up to 1 in 8 by age 80
** Female sex
*** <1% occurs in men
*** Masses in men are more likely to be non-cancerous than cancerous
** Reproductive factors (increased lifetime oestrogen exposure - relatively small contribution to overall risk. Particularly hormone receptor-positive cancers. )
*** Early age at menarche (<12yo)
*** Older age at menopause (>55yo double risk)
*** Nulliparity
*** Age at first live birth (first full-term pregnancy >30yo is double risk of first pregnancy <18yo)
*** Parity
*** Lack of breastfeeding
** Family history of breast cancer
*** First degree relatives RR 2-3
*** Much higher risk with pre-menopausal onset and bilateral breast cancer
** Genetic disposition
*** See separate topic
** Personal history of breast cancer
*** Magnitude of risk depends on age at diagnosis of primary, use of adjuvant chemotherapy and endocrine therapy
*** Absolute risk as high as 0.5-1% in younger patients
** White race
** Radiation exposure
*** RR 2-4, especially increased with mantle radiation <30yo