Familial cancer

Question 1

Features

Answer 1

Although the majority of cancers are not inherited,

some people carry inherited genetic mutations for certain cancers,

notably:

• breast and ovarian (linked)
• colorectal
• others on a lesser scale, such as prostate and melanoma.

Question 2

Key points

Answer 2

5% (at least) of cancers are familial

AD inheritance (i.e. 50% of offspring affected)

Main cancers:

• hereditary breast-ovarian cancer syndrome (BRCA1 and BRCA2 genes)
• hereditary non-polyposis colorectal cancer (HNPCC)
• familial adenomatous polyposis (FAP)

Question 3

Risk indicators

Answer 3

Two or more first- or second-degree relatives on one side of family with cancer

Age of onset <50 yrs

Bilateral or multifocal breast cancer

Question 4

Prevention

Answer 4

Identify familial cancer risk—refer to a familial cancer clinic

Breast cancer—regular imaging

Ovarian cancer:

• transvaginal ultrasound
• serum CA-125 test

Bowel cancer (high risk):

• HNPCC: annual or 2-yrly colonoscopy from 25 yrs or 5 yrs younger than youngest affected family member
• FAP: every 12 mths from 10–15 yrs to 30–35 yrs, then every 3 yrs after 35