Are your genetics putting you at risk for colorectal cancer?

cancer geneticsColorectal cancer is the second leading cause of cancer-related deaths in the United States, trailing only lung cancer in the number of deaths each year. The American Cancer Society estimates 50,310 people will die from colorectal cancer in 2014 alone. Unlike lung cancer, however, there are ways to successfully screen for and prevent this common disease.

In conjunction with Colorectal Cancer Awareness Month, I have outlined some factors health care providers consider in assessing an individual’s risk for colorectal cancer and determining the best approaches for screening and prevention.

Screening = Prevention

Colon cancer screening has been very effective in reducing the number of colorectal cancer diagnoses and deaths in the United Continue reading

BRCA Gene Mutations and Cancer

genetic risk breast cancerBRCA gene mutations have been in the news this week since Angelina Jolie announced she has the BRCA1 gene mutation and opted to have a bilateral mastectomy to reduce her risks of developing breast cancer. She became aware of her risk because her mother developed breast cancer in her mid-40s and died at age 56. What exactly are the so-called breast cancer genes and who should be tested to see if they are a carrier?

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Cancer Risk and Genetic Testing for BRCA1 and BRCA2

Unfortunately, cancer is a common disease, with the majority of the 200,000 new cases of breast cancer and the 20,000 new cases of ovarian cancer diagnosed each year being considered sporadic (a random chance event). However, about 5% to 10% of these cancer cases are due to an inherited gene mutation from either parent causing that individual to be at increased risk to develop breast and ovarian cancer.

From what we know, the two most common breast and ovarian cancer susceptibility

Genetics counselor Kara Milliron (l) and Dr. Sofia Merajver counseling a patient.

genes that can be inherited are BRCA1 and BRCA2. These two genes normally work to prevent cancer, but mutations (gene changes) can cause these genes to not work properly, which in turn sets up the conditions inside organs to produce an increased risk for developing cancer. Women who have a BRCA1 and/or a BRCA2 gene mutation have a 55% to 85% lifetime risk of developing breast cancer, and a 20% to 40% lifetime risk for developing ovarian cancer. This is a significant increase compared to the general population’s risk for breast cancer, which is 12.5%, and for ovarian cancer, which is 1.7%.

Genetic counseling and testing for mutations in these two genes is available and may provide information that patients can use to make medical decisions. For example, a woman with breast cancer who is considering a lumpectomy (a procedure that removes the tumor) or a mastectomy (which removes one or both breasts) may make a different surgical decision if she knows that she is at higher risk to develop a second brand new breast cancer in her lifetime. Genetic testing can also help a patient understand her ovarian cancer risk, along with helping identify relatives who could also be at increased risk. Individuals who are found to not be at increased risk for breast and ovarian cancer may not have to have increased surveillance for these cancers and that saves anxiety and cost. Continue reading

Understanding Childhood Cancers and How Genetics Could be Involved

Due to advances in research and collaborative studies, the National Cancer Institute reports that the long-term survival for children with cancer has increased from less than 10% to almost 80% in the past 50 years.

In general, cancer in children and adolescents is rare, with particular cancers occurring more often:

  • leukemia
  • lymphoma
  • brain and central nervous system tumor
  • tumors of developing tissues such as neuroblastoma, bone and soft tissue sarcomas
  • other cancers

While most cancers in children occur by chance, a small portion can be linked to an inherited genetic syndrome. One study of 1,100 pediatric cancer patients evaluated by genetic specialists confirmed an inherited cancer susceptibility syndrome in 3.9% and a suspected syndrome in another 3.3%*.

Though your child may already be seeing a number of specialists, referral to a geneticist or a genetic counselor can be another important piece which may provide a better understanding of why your child developed cancer and what this diagnosis means for siblings and other family members.

If other family members have been diagnosed with cancers, this could indicate an inherited syndrome that increases risks for cancer. Some of the pediatric cancers that may suggest an inherited predisposition to cancer and warrant a referral to a genetics clinic include:

  • medullary thyroid cancer
  • adrenal cortical carcinoma
  • retinoblastoma
  • sarcoma

Physicians and genetic counselors in the Cancer Genetics Clinic at the University of Michigan meet with patients and families to review your family history and determine if genetic testing may help clarify risks for additional cancers in the family. Targeted screenings and other risk reduction efforts can be taken in an effort to prevent cancer in the future.  The Cancer Genetics Clinic welcomes patients of all ages who may have questions about the risk of a genetic predisposition in their family.

Additional resources for questions regarding childhood cancer and genetics:

*(Merks et al, Am J Med Genet. 2005 Apr 15; 134A(2):132-43)

Is My Cancer Hereditary?

A new diagnosis of cancer, especially a rare cancer, can raise more questions than answers, even after meeting with many specialists.  Often patients diagnosed with a rare cancer wonder “Why did I get this cancer?”  “Does this mean my family members, my children, brothers or sisters are at risk for cancer too?”  “What can I do? What can they do?”

Sarcomas, cancers of the bone or soft tissue (including muscle), are one of these rare cancers that many people may not be aware of until a friend or loved one is diagnosed. For most patients diagnosed with sarcoma, the cause is not known.  There are some known risk factors that increase risk for sarcoma.  Excessive exposure to chemicals or radiation has been linked to an increased risk of developing sarcoma. Certain genetic, or inherited, conditions can also be associated with sarcomas.

If you, a friend or family member has been diagnosed with sarcoma, it may be helpful to ask some questions about your family history.  Sit down with your family members, and ask:

  • Have any other family members had cancer?  Relatives with sarcoma, breast cancer, colon cancer, leukemia or lymphoma are especially important.
  • How old were relatives when they were diagnosed with cancer?
  • Have any children in the family had cancer?

As you gather this information, share it with your oncologist or primary care physician, and talk with him or her about whether a referral for genetic counseling and genetic testing may be helpful. Genetic counselors and physicians in our Cancer Genetics Clinic can review your family history and help to determine if genetic testing may be needed.  They can also talk with you about possible results of genetic testing, and how this information would be used.  If the cancer risk in your family is inherited, special screening may be recommended to help with early detection and prevention.

Prostate Cancer and Genetics

One in six men will develop prostate cancer in their lifetime. Age and race are two of the most recognized risk factors, but some risk factors can be inherited. Large scale population studies of men who have brothers or fathers with prostate cancer have shown an increase in risk that is two to three times the general population.

Some clues to inherited risk within a family include:

  • Cancer diagnosed at earlier ages than typically expected (under 40)
  • Families with multiple individuals with prostate cancer
  • Other cancers in family members including:
    • Breast cancer
    • Ovarian or uterine cancer
    • Pancreatic cancer
    • Colorectal cancer

People concerned about their families’ history of prostate and other cancer may benefit from meeting with a genetic counselor in the Cancer Genetics Clinic to talk about cancer risk, possible genetic testing, screening options or research opportunities. Families who find that they are at a higher risk for prostate cancer and other cancers can benefit from increased screening and prevention options.

Approximately 5-10% of prostate cancers are thought to be related to high risk susceptibility genes, which can be passed from parent to child. Some genes are currently well known, while it is likely some still remain to be discovered. Some of these genes may also be linked to an increase in risk for additional cancers.

Research is ongoing at the University of Michigan Comprehensive Cancer Center and elsewhere to learn and discover new genes associated with a strong family history of prostate cancer.