If a woman’s mother, sister or daughter has had breast cancer, she has increased risks of developing the disease herself. But is this woman at greater risk of other types of cancer, too?
A recent study has found that a family history of cancer may increase the risk of close relatives developing the same type of cancer as well as different forms of the disease.
For example, this study showed that the close relative of a breast cancer survivor had more than a two-fold increased risk of ovarian cancer compared to women with no family history of breast cancer.
Eva Negri, MatSciD, head of the Laboratory of Epidemiologic Methods at the Mario Negri Institute for Pharmacological Research in Milan, Italy, was the corresponding author of the study.
The goal of this study was to look at the cancer histories of close relatives, particularly first-degree relatives (siblings, parents and children), of cancer survivors.
Dr. Negri and colleagues from Switzerland and France analyzed case-control studies (cancer cases versus healthy comparisons) on thirteen different types of cancer conducted between 1991 and 2009.
Cancer types included mouth and throat, nasal, larynx (voicebox), esophageal (tube between throat and stomach), stomach, colorectal, liver, pancreas, throat, breast, endometrial, ovary, prostate and kidney.
Data was collected on more than 12,000 cancer cases and more than 11,000 comparisons.
Along with information on family history of cancer, the researchers looked at age of diagnosis, body shape, lifestyle habits such as diet, smoking and alcohol use and personal history including reproductive history, use of birth control and hormonal therapies.
After accounting for all other factors, the researchers found the following:
- Women with a family history of colorectal cancer had a 1.5-fold increased risk of developing breast cancer.
- Female first-degree relatives of a breast cancer survivor had a 2.3-fold increased risk of ovarian cancer.
- Male first-degree relatives of a bladder cancer survivor had a 3.4-fold increased risk of prostate cancer.
- Close relatives of someone who had mouth (oral) or throat cancer had a four-fold increased risk of esophageal cancer.
- People with a first-degree relative who had cancer of the larynx had a 3.3-fold increased risk of developing oral or throat cancer.
- If cancer was diagnosed in an individual before the age of 60, the risk of close family members developing a different type of cancer was greater.
"Our results point to several potential cancer syndromes that appear among close relatives and that indicate the presence of genetic factors influencing multiple cancer sites," the authors wrote.
Dr. Negri said in a prepared statement, “These findings may help researchers and clinicians to focus on the identification of additional genetic causes of selected cancers and on optimizing screening and diagnosis, particularly in people with a family history of cancer at a young age."
This study was published July 24 in the Annals of Oncology.
This work was supported by the Italian Association for Cancer Research, the Italian Ministry of Education and the Swiss League Against Cancer.
No conflicts of interest were disclosed.