March 31, 2010 > Should You Consider Cancer Genetics Testing and Counseling?
Should You Consider Cancer Genetics Testing and Counseling?
Learn More at Upcoming Lunch and Learn Seminar
The billions of microscopic living cells inside your body each contain about 25,000 to 35,000 even smaller structures called genes. Those genes carry the information that determines the physical traits you inherit from your parents. Your straight hair, your long legs, your freckled face - even the dimples that appear whenever you smile - all have been passed along through generations of your family through the genes.
Unfortunately, your genes can also carry more sinister traits, including an inherited risk for various forms of cancer.
"The vast majority of cancers are not due primarily to an inherited genetic risk," says Nicolette ("Nicki") Chun, MS, CGC. "Nevertheless, in certain families, errors in the genes called mutations can result in a high predisposition toward developing specific types of cancer."
A certified genetic counselor, Chun evaluates and counsels patients regarding genetic risks for cancer as part of a collaborative effort between Washington Hospital's Cancer Genetics Program and the Cancer Genetics Clinic at Stanford University Medical Center.
To help people in the local community learn more about genetic testing and counseling, the Washington Women's Center will be offering a special "Lunch and Learn" class featuring Chun and medical oncologist Vandana Sharma, M.D., Medical Director of the Washington Cancer Genetics Program. The class is scheduled for Tuesday, April 6 from noon to 1 p.m. in the Washington Women's Center Conference Room at 2500 Mowry Avenue in Fremont.
According to Chun, the most likely candidates for inherited cancer risks are people who have a family history of:
* specific cancers repeated in multiple generations,
* a combination of related cancers such as breast and ovarian cancer or colon and uterine cancer, and
* younger ages at the time of cancer diagnosis.
"There are a few dozen cancer-related gene mutations for which we can do testing, but the two most common are breast-ovarian cancer syndrome and Lynch syndrome," Chun explains. "Breast-ovarian cancer syndrome is often related to mutations on the BRCA1 and BRCA2 genes. Lynch syndrome involves a genetic mutation in one of five genes and is the most common inherited risk factor for colon cancer. Lynch syndrome also increases the chances of developing uterine and ovarian cancers in women, as well as stomach, bile duct and urinary tract cancers."
Chun notes that having a particular gene mutation increases the person's risk for cancer, but it does not automatically mean the person will develop cancer. "For example, if we find mutations on the BRCA1 or BRCA2 genes, that means the person has up to a 65 percent lifetime risk of developing breast cancer," she says. "Also, women who've had this type of breast cancer once are up to 50 percent more likely to develop a new primary breast cancer."
Genetic testing for inherited cancer risks faces some limitations. "We don't have comprehensive tests available for all inherited cancer risks," Chun cautions. "For example, we're not as far along with tests for prostate cancer and other types of cancer such as lung cancer and brain tumors. Also, if we test a person for mutations on the BRCA1 and BRCA2 genes and get a negative result, that test would not be helpful for any of their relatives in determining their risks for breast cancer. We know there are other breast cancer genes that we can test for yet."
For patients who do test positive for a cancer-related genetic mutation, that knowledge can help them and their physicians take preventive measures to lower their risk factors. "Patients who know they have an inherited cancer risk may benefit from more frequent screenings, surgery or preventive chemotherapy," Chun says. "It's also helpful to be able to pass that information along to other family members who may also be at risk."
Learn More About Genetic Testing
To register for the class on April 6, please visit www.whhs.com and click on the link for "Genetic Counseling and Testing" under Upcoming Seminars. For more information about the Washington Cancer Genetics Program, visit www.whhs.com/cancergenetics