Insuring carriers of inherited colorectal cancer genes


J.A. Lowden MD, PhD, FRCPC, Vice President and Chief Medical Director, Crown Life Insurance, Regina, Saskatchewan

The Human Genome Project is perhaps the most exciting collaborative effort of scientists and engineers since the race to the moon in the 1960's. New science, new technologies and an incredible accumulation of new data pour forth from laboratories around the world at a rate far exceeding the original plan. They bring more specific diagnoses, better prospects for genetic counseling and opportunities for new therapies but these developments also bring concerns to bioethicists, to legislators, to consumer activists and to much of the lay public who feel the new knowledge may be used to the disadvantage of some. In particular, the advances bring concern to families who know they are at risk of carrying certain mutations.

The new genetic tests discovered under the auspices of the HGP may predict diseases which will occur in the future in people who are apparently well when the test was conducted. They may identify individuals who are presymptomatic but will certainly become ill in time, or they may identify those who are merely predisposed to a disease and may or may not succumb to it. The genes which cause inherited forms of colorectal cancer, hereditary nonpolyposis colon cancer (HNPCC) and familial adenomatous polyposis (APC), are transmitted as autosomal dominants and result in bowel cancers in a large percentage of those who carry mutations. They are thus predisposing, not presymptomatic, mutations.

As these tests become available the question arises, who wants to know this genetic information about their personal future and what will, or can, they do about it? To many, the burden of knowledge about their health in later years is too complex to handle. They would rather wait and find out when it happens. Others, however, are eager to know so they can make more effective life plans. Knowledge of one's status as a carrier of an HNPCC or APC mutation can be life-saving when the information is used to plan a regular program of monitoring with occult blood samples and colonoscopy. Avoidance of genetic testing may lead to overuse of colonoscopy or perhaps to a late diagnosis when little can be done to mitigate the problem.

Some at-risk individuals avoid genetic testing for HNPCC or APC mutations because of concerns about unfair discrimination by employers, insurers and others who might acquire access to their genetic status. This is a real problem because these tests can save lives. Hereditary colon cancer is a preventable disease and as a life insurer, I am clearly interested in saving lives. People who avoid having tests, may avoid the other preventative measures like colonoscopy and thus risk an unfortunate early death.

Life insurance is sold to provide financial protection against unanticipated early loss. Some people will die before they reach a normal life expectancy and insurance coverage will provide a benefit to their survivors. Insurance policies are priced recognizing that these early claims will be made. Insurers try to avoid expected early claims by reviewing the health status of their applicants. They assess the risk for each policy they offer and determine how that life risk compares with that of a standard group of people of the same age and gender. To do so they need to know as much about each individual's specific risks as possible. When an applicant has a greater than normal risk, they are charged a larger premium or they may be declined. In practice over 90 per cent of life insurance applicants are offered policies at standard rates. About 5 per cent are rated and usually fewer than 3 per cent are declined.

Before the advent of genetic testing for hereditary colon cancer, it was common for insurers to decline or rate all applicants from high risk families. If the individual came from a family with three or more first degree relatives with colon cancer, their risk could be as high as 50 per cent and the mortality risk was at least 25 per cent. No insurance policy is priced to cover those costs. Furthermore, when the information is known to the applicant but denied to the insurer, the applicant might well be inclined to purchase excess insurance because they anticipate an early claim.

Today things are changing. Attending physicians are now considering performing genetic tests in their patients from high risk families. People want to know if they are at risk of developing the same disease that their mother had and they ask their physicians to get them tested. Half the children in these families will not carry the mutation which affected their parent. They are clearly not at risk for this type of bowel cancer and are considered as standard risks by insurers. The other half are at risk but I believe that they are insurable.

Early diagnosis of colon cancers definitely leads to better prognosis. Colon cancers are usually slow growing and they can be visualized by colonscopy. While there are other cancer risks in some patients with these mutations, they are not frequent and from a life insurance perspective, can be covered by modest premium increases. When they adopt simple prevention strategies, carriers of HNPCC and APC mutations are insurable.

What about doing screening tests on all insurance applicants for these mutations? Would this not identify many people who do not realize they are at risk and thus save many lives? This point has been debated in the scientific and insurance literature for the past few years but the numbers make it unlikely that any company will follow such a course. Hereditary colon cancers occur in about 1:200 individuals, most of whom know their own risk. Reduced penetrance (people who carry the mutation but do not get cancer), early parental death and unknown parentage may obscure the heritable nature of the disease in some families but when the prevalence of a disease is this low, the predictive value of any test falls and testing of all applicants would result in far more false positive tests than true. False positive tests would cause untold concern an cost more than the protective value they would add. It is unlikely that insurers will ever consider doing HNPCC or APC tests on all their applicants.