Whilst all cancers develop as a result of gene mutations, not all of these mutations are inherited from a parent. The majority of cancers are thought to be sporadic, occurring in individuals as a result of aging, and / or environmental exposures.
Hereditary cancers are attributable to changes in specific genes that are passed from a parent to their offspring. Individuals with these germline mutations associated with a high probability of cancer development will have a higher likelihood of developing cancer within their lifetime than individuals who have not inherited the mutation. Approximately 5% to 10% of all cancers are hereditary.25 Known hereditary cancer syndromes and their associated malignancies are summarised below: 25
|Hereditary Cancer Syndrome||Major associated malignancy|
|Hereditary breast and ovarian cancer||Breast||Fallopian tube|
|Hereditary colon cancer syndromes||Colorectal||Urinary tract|
|Familial adenomatous polyposis||Colon adenocarcinoma||Brain|
|Duodenal carcinomas||Childhood hepatoblastoma|
|Li-Fraumeni||Osteogenic and chondrosarcoma||Brain (glioblastomas)|
A familial cancer pattern is characterised by an increase in the number of cancers within a family, more than what is expected by chance alone.25 Familial cancers may be associated with chance clustering of sporadic cancer cases within families, genetic variation in lower penetrance genes, a shared environment, or combinations of these factors.26
The SCN can be involved in cancer risk assessment and cancer risk counselling or referral to appropriate services. There are significant complex issues related to genetic risk assessment counselling and testing. A number of clinical guidelines and standards have been developed to support clinicians in this field.26, 27
Familial Risk Assessment - Breast and Ovarian Cancer, Cancer Australia. 2014
Genetics & risk. Cancer Council Victoria
Cancer. Health Centre for Genetics Education
Cancer Genetics. eviQ
Genetic / Familial High-Risk Assessment: Breast and Ovarian. National Comprehensive Cancer Network, 2014.
Familial aspects of bowel cancer: a guide for health professionals(PDF, 172KB). Australian Cancer Network, 200827