Know your history. Period. When your family history changes, or new forms of cancer arise in your bloodline, tell your doctor. Family history remains one of the best ways to identify people at high risk for breast, prostate and colon cancer, and now new research suggests that updating your doctor between ages 30 and 50 about any close relatives who develop these cancers may lead to lifesaving changes in how and when you are screened.
Researchers analyzed data on adults with a personal or family history of cancer or both who were part of a cancer registry called the Cancer Genetics Network. Changes in self-reported family history of cancer occur throughout adulthood, and this increases steeply before the age of 50 for breast and colorectal cancer, and before the age of 60 for prostate cancer.
At age 30, 2.1% of participants met the criteria for high-risk screening for colorectal cancer, compared with 7.1% at age 50. For breast cancer, the rates were 7.2% at age 30 and 11.4% at age 50 and for prostate cancer, the rates were 0.9% at 30 and 2% at age 50.
Dianne M. Finkelstein, of the Massachusetts General Hospital Biostatistics Center in Boston explains in detail:
“Family history is very important, and it can give [individuals] a sense of whether they are at elevated risk for certain types of cancers, and this could impact how they are screened. If anyone in your family gets cancer, you should know the age when they were diagnosed and the original site of the cancer. Let’s say you are 35, and there is no one with cancer in your family and then you go back to your doctor, and your older brother is diagnosed with colon cancer. This information changes the doctor’s strategy with respect to colon cancer screening and they may find any cancer earlier, which may change the outcome.”
There are two main types of genetic cancers. Familial cancers are cancers caused by variants in multiple genes and the environment all working together. In this case, each genetic variant causes a slight increase in risk. The overall risk of developing cancer depends on the number of cancer risk genetic variants that a person inherits and what environmental factors interact with those genes. Although these cancers appear to cluster in families, they don’t follow the typical rules of inheritance.
Hereditary cancers are cancers that are associated with a change in a single cancer susceptibility gene (like BRCA1 or BRCA2). These genes account for a very small percentage of all cancers. In fact, only 5-10% of breast and colon cancer cases are caused by changes in a single gene. Although everyone who carries a change in a cancer susceptibility gene does not get cancer, the risk is increased greatly, usually to 50% or higher. These types of genetic changes are passed on in an autosomal dominant inheritance pattern in families. This means that each child of an individual that carries a gene change in a hereditary cancer susceptibility gene has a 50% chance of inheriting the gene change.
Dr. Robert Smith, director of the cancer screening national office of the American Cancer Society stated:
“The public needs to understand that family history is important and good communication with first and second degree relatives is essential. (Doctors) should update this information every time they see the patient and make it clear that if there is a change, it needs to be reported. Sometimes the information isn’t collected or collected thoroughly enough. Primary care physicians have to get to a point where they recognize certain family history as high risk and send patients to a genetics specialist. Gains in genetic medicine are not worth as much as they might be if people don’t act on this information.”
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Written by Sy Kraft