Cancer Genetics: Finding and Treating Cancer Before It Occurs

Most people would like to see into the future. Tempting, but what if you saw that you and your children were certain to have cancer? That's exactly what happened to the Wisconsin family of Lisa Lyle.

With the help of professional genetic counselors, advanced genetic screening techniques and Medical College of Wisconsin cancer specialists, they faced and found a genetic timebomb in their midst and lifesaving options to defuse it, thanks to the Cancer Genetics Screening Program at Froedtert & The Medical College of Wisconsin.

Genetic screening revealed that Lisa, her three young children, her mother and some of her siblings have a gene mutation that virtually guarantees they will develop a rare form of thyroid cancer. The program's multidisciplinary team of experts has helped Lisa's family, and a half-dozen other local families concerned about inherited cancers, find and confront some difficult facts, and most importantly, make well informed decisions.

Breast Cancer specialist Philip N. Redlich, MD, PhD, Associate Professor of Surgery at MCW, chaired the cancer committee that established the program. He cautions that, while genetic testing for a number of cancer susceptibility genes has become available in recent years, and many people have a family history of cancer, these genes may account for only 5% to 10% of all cancer cases.

Genetic screening is now available for breast, ovarian, colon, prostate and some skin cancers. "Those with the genes, however, face a significantly greater risk of developing cancer in their lifetime," Dr. Redlich says.

On learning that several older relatives had rare medullary thyroid cancer -- a type accounting for only 10% of all thyroid cancers -- Lisa's sister Barbara sought help in the screening program and underwent genetic screening. She also urged Lisa and other family members to do so as well. After Lisa was screened, certified genetic counselor Dawn Allain gave her a confidential assessment and counseling about the gene and its risks.

Ironically, screening revealed that Barbara did not have the gene, giving her the benefit of knowing that it would never appear in her own children. Counseling, to help her cope with the fact that so many other members of her family were affected, was another benefit.

Consultation with MCW cancer specialists in the program has empowered the affected family members and their family physicians with a lifesaving option to prevent this cancer, and to plan long-term strategies to keep two other potentially serious manifestations of the gene at bay.

Lisa and her siblings decided to have their thyroids removed immediately. Lisa will also have her children undergo similar surgery. For each, a daily pill will compensate for thyroid function for the rest of their lives.

Medullary thyroid cancer is by far the most common of three possible manifestations of their disease, Multiple Endocrine Neoplasia Type 2A (MEN2A), according Gretchen M. Ahrendt, MD, formerly an Assistant Professor of Surgery at MCW, who performed the thyroid surgery on Lisa, her mother and several of Lisa's siblings.

Between 95% and 100% of those with the gene develop this cancer, most by their 20s. However, it can also occur later or earlier in life, including early childhood, according to Dr. Ahrendt. In MEN2A families, this cancer is often slow-growing, and if caught early, has a good prognosis. Left untreated, it spreads to lymph nodes in the neck and elsewhere in the body, most commonly to the lungs and liver.

"Knowing that we can provide genetic tests that will either tell a parent 'your child needs surgery that is curative,' or 'your child does not have the potential for the disease and will not require lifelong screening for all the manifestations of this gene,' is, I believe, very useful for families," Dr. Ahrendt says.

According to Allain, about 40% of those with the gene will also develop pheochromocytoma, an abnormal growth of the adrenal glands. For most people, the condition is not cancerous, but it can be serious, and lifethreatening if not treated. Another 10% to 30% of people with MEN2A will develop hyperplasia, or abnormal growth, of the parathyroid glands. Parathyroid hyperplasia has to be treated, but it is usually not a cancerous condition. People with the gene may develop one or more of these conditions over a lifetime, but only 25% develop all three. Forewarned of these other manifestations, lifelong medical vigilance and screening can ensure early intervention if either should develop.

Dr. Redlich says that others who may benefit from cancer genetic counseling include those diagnosed with certain genetic conditions which predispose toward tumor development, and cancer survivors who suspect that they have had an inherited form, in order to asses their risk of a second cancer, or cancer risk in their children.

For those concerned about the possibility of an inherited form of cancer, he gives the following factors that suggest the possibility:

• several closely related family members with cancer, on either maternal or paternal side of the family
• early age onset of cancer
• bilateral disease
• multiple primary cancers in more than one individual
• unusual or rare cancers, such as breast cancer in men

For more information on the Cancer Genetics Screening Program, call 414-266-3784.

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.