Hormonal Imbalances
Breast cancer risk may be affected by levels of female sex hormone, oestrogen, and male hormone, testosterone. Women’s bodies contain small amounts of the male hormone testosterone. Women with higher levels of oestrogen and testosterone in their blood after menopause have a greater risk of breast cancer compared to healthy women. Until menopause, women with higher testosterone levels in their blood also have a greater risk of breast cancer.
For women with higher levels of the hormone called insulin like growth factor 1 (IGF-1), there is an increased risk of breast cancer. It’s unknown what regulates blood levels of IGF-1 and it is likely related to our genes, and environmental factors.