Treatments which reduce the level of these hormones, or prevent them from working, are commonly used in people with breast cancer.
If you are confirmed to have breast cancer, further tests may be needed to assess if it has spread.
The usual first symptom is a painless lump in the breast, although most breast lumps are not cancerous and are fluid filled cysts, which are benign.
It's not just one or two.
Speaking exclusively to the MailOnline, Duncan said: 'Some of my really good friends in the industry have battled with cancer and some I knew really well: Sarah sadly passed away after losing her battle.