TUESDAY, Sept. 21, 2004 (HealthDayNews) -- Knowing your family's medical history can provide important clues to help your doctor evaluate your individual risk of cancer and make decisions about what screening tests you need.
This is true even when those histories are "self-reported" -- relayed by a patient to his or her doctor, a new study finds.
Researchers have long wondered if self-reported family histories were accurate enough to properly assess risk. For example, you may tell your doctor that your father had melanoma because he told you that he had skin cancer. He might have had, however, squamous or basal cell skin cancer -- much less deadly forms of the disease.
"Family history information might change how we manage a patient," said Dr. Harvey Murff, an assistant professor of medicine at Vanderbilt University Medical Center and the department of Veterans Affairs in the Tennessee Valley Healthcare System.
"So, our question was -- that information: How good is it?" said Murff. He and researchers from the Sarah Cannon Cancer Center in Chattanooga, Tenn., and Brigham and Women's Hospital and the Dana-Farber Cancer Institute, both in Boston, reviewed 14 studies on self-reported family histories of cancer.
The results of their review appear in the Sept. 22/29 issue of the Journal of the American Medical Association.
According to the study, people who have first-degree relatives -- that means a parent or sibling -- with breast, ovarian, endometrial, colon, and prostate cancer, have a higher risk of developing these cancers.
The 14 studies included in the current analysis all contained self-reported information on family history. But then the researchers also confirmed the cancer history through death certificates, cancer registries, or medical records.
The researchers found that self-reported histories of cancer in the family were most accurate for breast and colon cancers. Self-reported family histories of ovarian, endometrial, and prostate cancers were not as accurate as the breast and colon cancer reports.
Murff said this may be because these are less common tumors.
Dr. Kristin Skinner, chief of the division of surgical oncology and director of the breast center at New York University's Clinical Cancer Center, suggested another reason.
"Until recently, cancer was a dirty word and no one really talked about it. Plus, many women don't like to talk about their private parts, so to talk about cancer of the ovary or uterus was very hard," Skinner said. But public awareness campaigns have helped people to talk about cancer more openly, she added.
Of the new study, Skinner said, "Most people in risk assessment have felt that self-report is useful when patients have the information." However, "it's always nice to pool data so that you have a bigger sample size," she added."
"Family history does significantly impact your risk of many cancers, and to effectively understand what your particular risk is, you need to know what your family history is," said Skinner. That means you should find out what all of your family members have died from and what age they were when they died, she said.
Skinner added that while family history is an important risk factor, many people who develop cancer have absolutely no family history of the disease. So, she said, having no family members with cancer doesn't mean you don't need to undergo cancer screening tests.
In a related study in the same issue of the journal, doctors and lawyers from Memorial Sloan-Kettering Cancer Center in New York City and from Georgetown University's Center for Law and the Public's Health discuss the difficult situations that can arise from hereditary disease risks.
The study cites three lawsuits that have been brought against doctors who failed to warn relatives about a patient's hereditary disease. In two of the cases, patients' children went on to develop the disease. And in the third, a couple went on to have another child, which they claim they wouldn't have done if they had known about that daughter's hereditary condition.
The problem for doctors, argue the authors, is that they cannot warn other family members without a patient's consent; doing so would breach that patient's confidentiality. The authors suggest that doctors should encourage their patients to share this information with their family members.
"We believe that health-care professionals have a responsibility to encourage -- but not to coerce -- the sharing of genetic information in families," they write.
To learn more about the risks for cancer, including family history, visit the American Academy of Family Physician's FamilyDoctor Web site.