Family History of Cancer May Raise This Risk, Too
Large European study looked at people with close relatives who'd been affected
"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," said study co-author Dr. Eva Negri.
"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," said Negri, head of the laboratory of epidemiologic methods at the Mario Negri Institute for Pharmacological Research in Milan, Italy.
The researchers from Italy, Switzerland and France looked at 12,000 cases of cancer occurring in 13 different parts of the body between 1991 and 2009, and matched them to control cases of 11,000 people without cancer. For both groups they collected information on any cancer in the family, as well as data on health and lifestyle factors that can influence a person's cancer risk.
"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," Negri said.
The study's reliance on survey data, however, is a significant weakness that may have caused the authors to overstate the odds of cancer risk, said Mia Gaudet, director of genetic epidemiology for the American Cancer Society.
"At the time the cases are reporting family history, they already know they have cancer," Gaudet said. "It's an emotional time, and they are more likely to recall family members who have had cancer."
By the same token, the comparison patients without cancer may be less likely to recall family instances of cancer because they don't have the same motivation. "This can really introduce differences in how individuals recall any particular exposures, and this difference could be particularly profound when it comes to cancer," Gaudet said.
Follow-up genetic research into the potential associations between different types of cancer reported by the European researchers is warranted , she said.
In addition, people with a family history of cancer might want to discuss with their physician whether they should see a genetic counselor to assess their cancer risk, Gaudet said.