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Cancer Genetics

Cancer Testing with Family History



I have an extensive amount of cancer in my family, primarily on my father`s side. My father, grandfather, and aunt died from lung cancer. My mother and paternal grandmother died from breast cancer. My maternal grandfather has a history of colon cancer. I need to know what type of yearly testing I should have done? I am 42 years old. Are there study programs I can be involved with? I would be willing to participate in a research program if any are available. Is there a blood test available to detect cancer?


The cancers you have listed in your family (lung, breast, colon) are the three most common forms of cancer. It is important to realize that cancer, in itself, is common. One out of every three individuals in the general population develops cancer within their lifetime. For example, one out of every 12 women develop breast cancer; colon cancer is seen in 1 out of every 15 individuals; likewise, lung cancer is one of the most common cancers seen, especially in those individuals who have a significant personal history of cigarette smoking or environmental exposure (asbestos, workplace chemicals).

All in all, the majority of cancer (80% of cases) occur in the absence of a significant family history and are caused by acquired DNA changes within our cells. These changes are often a result of environmental exposures. Acquired DNA changes cannot be passed from one generation to the next so this type of cancer is considered sporadic (a chance event) and NOT hereditary.

A single inherited factor is felt to be responsible for about 5-10% of ALL cancers. Inherited DNA changes are passed down to us from our mothers or fathers through the egg or sperm. Individuals born with a single change in a particular section of the DNA involved with cancer susceptibility will have a much greater chance for developing certain cancers in their lifetime. However, not everyone with a cancer susceptibility gene will develop cancer.

Since 5-10% of ALL cancers may be inherited, it is more important to look at the PATTERN of cancer occurrence in a particular family, than to look at a specific kind of cancer. Some important `clues` we use to find those families which have hereditary cancer, and could benefit from professional genetic counseling/testing include:

1) Cancer that occurs at an unusually young age. For example, the average age for diagnosis of breast cancer in the general population is 56; average for diagnosis of colon cancer is 65. In hereditary cancer cases, the age of onset is seen much earlier.

2)Multiple primary cancers at the same site [not cancer spreading to another part of the body].

3) Associated cancers in several close relatives [breast cancer and ovarian cancer; colon cancer and uterine cancer].

4) Cancer in an unusual sex [male breast cancer].

5) A primary cancer occurring in paired organs [breast cancer occurring in both breasts].

6) Rare cancers [for example, endometrial or kidney cancer].

7) An individual who has had two or more primary cancers [ovarian cancer diagnosed after breast cancer].

8) A collection of tumors that are consistent with a specific cancer syndrome, for example, hereditary nonpolyposis colorectal cancer [HNPCC].

If any of these `clues` seems to fit the cancer(s) seen in your family, it may be helpful to seek professional cancer genetic counseling. A genetic counselor can provide the necessary cancer risk assessment, and discuss available gene testing and possible entry into research studies.

In being as complete as possible in your cancer surveillance screening, especially with the knowledge that your mother had breast cancer, and depending on her age at diagnosis, you may need earlier or more frequent cancer screening. In the general population, the American Cancer Society recommends that women perform monthly breast self-examination beginning at age 18, receive annual (yearly) clinical breast examinations from a physician beginning at age 20,and receive annual mammography beginning at age 40. The American Cancer Society recommends that men and women in the general population receive colorectal cancer screening including annual fecal occult blood tests (testing the stool for blood) and sigmoidoscopy (or colonoscopy) every 3-5 years beginning at age 50.

To find a Cancer Genetic Counselor in your area and additional information on hereditary cancer, you can search the websites listed below.

Related Resources:

National Society Genetic Counselors
Netwellness links

For more information:

Go to the Cancer Genetics health topic, where you can:

Response by:

Kevin   Sweet, MS, CGC Kevin Sweet, MS, CGC
Cancer Genetic Counselor
College of Medicine
The Ohio State University

Judith A Westman, MD Judith A Westman, MD
Associate Professor, Clinical Internal Medicine, Pediatrics and Medical Biochemistry
College of Medicine
The Ohio State University