Between five and 10 per cent of prostate cancers have a hereditary component, which may be associated with identifiable germline detects in genes such a BRCA1 or BRCA2 (hereditary breast ovarian cancer syndrome), HOXB13 (hereditary prostate cancer), or genes involved in DNA mismatch repair (Lynch syndrome) (Giri et al. 2018). Men should be counselled about possible hereditary/inheritable risk if:

• their family history suggests a pathogenic BRCA1 or BRCA2 gene variation
• three first- or second-degree relatives have been diagnosed with prostate cancer
• two first- or second-degree relatives have been diagnosed with prostate cancer, with one relative being diagnosed before the age of 50 years (RACGP 2019)
• young at the age of diagnosis (< 50–55 years) in a patient or first-degree relative
• there is a family history of prostate, breast or ovarian cancer.

Men should engage in shared decision making about genetic testing.

Genetic testing should only be performed through a familial cancer service, with appropriate genetic counselling available.

For general practitioner referral guidelines for cancer genetics assessment, see General practitioner referral guidelines for cancer genetics assessment.

There is emerging data that germline mutations in genes involved in DNA repair (e.g. BRCA1 or BRCA2 and mismatch repair genes) are more common in patients with advanced disease, and therefore may be significant in the patient’s prognosis. In patients without a family history, it is unclear if early detection and changes in management based on germline testing is advantageous.