People with a family history of cancer are at an increased risk of developing both the same and different types of cancer themselves, a new study has found.

Italian and Swiss scientists analysed 12,000 cases of cancer in 13 different sites of the body, including the breast, womb, prostate, kidneys, liver and pancreas. All of the cases occurred between 1991 and 2009 and these were then compared to 11,000 people without cancer.

Information on cancer within families was collected, as well as other relevant information, such as age at diagnosis, lifestyle habits, medical history, body shape and the use of oral contraceptives.

The study confirmed previous known links, such as the fact that people have an increased risk of developing the same type of cancer as a close relative. However, it also found an increased risk of developing other types of cancer.

For example, if a first-degree relative, such as a sibling, had cancer of the larynx (voice box), a person had a 3.3-fold increased risk of developing oral and pharyngeal cancer. The pharynx is a hollow tube inside the neck.

If a first-degree relative had oral or pharyngeal cancer, a person had a four-fold increased risk of developing cancer of the oesophagus (gullet or swallowing tube).

Meanwhile, women had a 2.3-fold increased risk of developing ovarian cancer if they had a first-degree relative with breast cancer. And men had a 3.4-fold increased risk of developing cancer of the prostate if they had a first-degree relative with bladder cancer.

"Besides confirming and quantifying the well-known excess risks of people developing the same cancer as their first-degree relative, we have identified increased risks for developing a number of different cancers," explained Dr Eva Negri of the Mario Negri Institute for Pharmacological Research in Italy.

The scientists also found that if people were diagnosed with certain cancers before the age of 60, the risk of a family member developing a different type of cancer was even greater.

"A major strength of our study is that we were able to adjust our analyses for tobacco, alcohol and a number of other lifestyle habits, which most previous studies have not been able to do," Dr Negri noted.

She suggested that some of the links between different types of cancers could be due to shared environmental factors, such as family habits of drinking alcohol and smoking.

However, the results ‘point to several potential cancer syndromes that appear among close relatives and that indicate the presence of genetic factors influencing multiple cancer sites', she said.

"These findings may help researchers and clinicians to focus on the identification of additional genetic causes of selected cancers and on optimising screening and diagnosis, particularly in people with a family history of cancer at a young age," Dr Negri added.

Details of these findings are published in the journal, Annals of Oncology.