Family History May Raise Risk of Cancers At Other Sites

Previous studies suggest that the risk of cancer at a specific site is higher in subjects with a family history of cancer at that same site.  Researchers from the Istituto di Ricerche Farmacologiche Mario Negri (Italy) analyzed data collected on participants in a network of case-control studies on 13 cancer sites, conducted between 1991 and 2009, that included 12,647 cancer patients identified at hospitals in Italy and the Canton of Vaud in Switzerland; as well as 11,557 control subjects. The team  collected data from all participants on history of any cancer in first-degree relatives, as well as information on such things as sociodemographic characteristics, anthropometric measures, lifestyle and dietary habits, and personal medical history.  For each relative with a history of cancer, the participant was asked about his or her vital status at the time of interview, current age or age at death, cancer site, and age at diagnosis. Whereas a family history of cancer at any site was associated with an increased risk of cancer at the same site, for most cancer sites, the link with family history was stronger when the participant was younger than 60 when he or she was affected.  That is, the investigators reported that  the odds ratio for ovarian cancer, given a family history of the disease, was 20.1 when the participant was younger than 60 and 3.2 when she was 60 or older.  And the researchers also found significantly increased risks for: Oral and pharyngeal cancer given a family history of laryngeal cancer, with an odds ratio of 3.3; Esophageal cancer, given a family history of oral and pharyngeal cancer, where the odds ratio was 4.1; Breast cancer, given a family history of colorectal cancer or hemolymphopoietic cancers, where the odds ratios were 1.5, and 1.7, respectively; Ovarian cancer in the light of a family history of breast cancer, with an odds ratio of 2.3; and prostate cancer, given a first-degree relative with bladder cancer, where the odds ratio was 3.4.  The study authors submit that: “Our results point to several potential cancer syndromes that appear among close relatives and may indicate the presence of genetic factors influencing multiple cancer sites.”