aetiology

Last reviewed 01/2018

Aetiology of the disease is unknown but the following factors have been known to increase the risk (1):

  • oestrogen exposure/androgen insufficiency (2)
    • testicular abnormalities - undescended testes, congenital inguinal hernia, orchiectomy, orchitis
    • Klinefelter’s syndrome - the risk is 50-fold greater than in the general male population
    • obesity - due to an increase the oestrogen-testosterone ratio
    • liver cirrhosis
    • exogenous oestrogen therapy
  • benign breast conditions - history of breast trauma and  nipple discharge

  • chest wall radiation exposure and other occupational factors (chronic heat exposure) (3)

  • men with a family history of breast cancer - 2.5 times the risk of developing breast cancer

  • mutations in BRCA1 and BRCA2 (2)
    • the association between male breast cancer and BRCA is stronger in patients with BRCA 2 mutations than in BRCA 1 mutations. 
    • according to estimations around 4-40% of male breast cancer patients carry a mutation in BRCA2 and in upto 4% of patients carry BRCA 1 mutations 
    • the life time risk for breast cancer in
      • a male BRCA2 mutation carrier is ~7% which is estimated to be 80-100 times higher than for the general population
      • a male BRCA1 mutation carrier is just over 1% (2)

The importance of gynecomastia as a risk factor for male breast cancer is unclear (3)
Reference: