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Dr. Anand Saggar

Dr. Anand Saggar - MBBS, CCST, FRCP

Medical Genetic Specialist

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07970 886663

Familial Breast Cancer

Epidemiology

Breast cancer is the most common form of cancer affecting women with a lifetime risk of 9-11% predominantly occurring post-menopause.  NICE guidelines have been introduced that identify risk of breast cancer according to family history.  See Box 1 for risk factors and Box 2 for factors suggestive of inherited disease.

Genetics

  • Mutations in the breast cancer 1 (BRCA1, chromosome 17q) and breast cancer 2 (BRCA2, chromosome 13q) genes cause 2-3% of breast cancer. 
  • Approximately 10% of women with onset of breast cancer under the age of 40 years have a BRCA1 or 2 gene mutation.
  • Inheritance is autosomal dominant.
  • Cancer risks with BRCA1:
  • Up to 70 years of age, breast cancer 65%, ovarian cancer 39%.
  • Cancer risks with BRCA2:
  • Up to 70 years of age, breast cancer 45%, ovarian cancer 11%.  BRCA2 gene carriers are also particularly at risk of pancreatic, prostate and male breast cancers and malignant melanoma

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Screening

  • Monthly self-breast examination
  • According to NICE guidelines, women at increased risk of breast cancer should be offered annual mammography from 40-49 years of age and thereafter once every 3 years.
  • Breast MRI screening is also available for those women at very high risk of breast cancer at a young age or known gene mutation carriers, starting at age 30 for BRCA1/2 and age 20 for Li-Fraumeni  (TP53) mutations.
  • Screening for ovarian cancer in women at increased risk is currently being assessed in a research study, UKFOCCS, which includes pelvic trans-vaginal USS and CA-125 measurements.

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Risk factors for breast cancer:

  • Early menarche & late menopause
  • Nulliparity and lack of breastfeeding
  • Oral Contraceptive Pill & Hormone Replacement Therapy
  • Obesity
  • Alcohol
  • Family history of breast/ ovarian cancer
  • Family history of other cancer syndromes eg Peutz-Jeghers syndrome, Li-Fraumeni syndrome, Cowden syndrome, Het-erozygous carriers for ataxia telangiectasia.

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Factors suggesting inherited breast cancer:

  • Autosomal dominant inheritance pattern
  • Young age of onset
  • Multiple primary tumours in an individual
  • Breast, ovarian and prostate cancer occurring on same side of family
  • Breast cancer in a male relative
  • Oestrogen receptor (ER) negative breast tumour
  • Ethnic origin: Ashkenazi Jewish, Icelandic

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