With a speed so rapid that many medical experts are being taken aback, genetic tests that tell if a person is likely to get cancer are entering the marketplace.
Those in favor of testing say people have a right to know if they are at increased risk and it would be unethical to deny them that knowledge. They say people who harbor cancer genes may be helped by undergoing frequent screening so they can get early treatment.
But opponents say it is too soon, the tests still are research tools, it is not clear if patients will be helped or harmed by knowing their likely medical futures and, in some cases, it is not clear how to interpret test results.
The tests look for mutated genes that enormously can increase a person’s risk of getting breast cancer, colon cancer, melanoma or thyroid cancer. Another gene points to an inherited predisposition to any of a variety of cancers, including breast cancer and brain tumors.
The tests, which cost $800 for the first family member and $250 for each additional member, involve analyses of genes obtained from blood samples or, in the case of the melanoma gene, from swabbings of the inside of a patient’s cheek.
The genes were discovered only recently. The melanoma gene was reported in September, for example, and the breast cancer gene in October. Some researchers say they only are beginning to understand the consequences of inheriting one of these genes.
Dr. Francis Collins of the National Institutes of Health in Bethesda, Md., is director of the Human Genome Project, the federal effort to map the entire human genetic sequence. Collins said the effort to market the genetic tests “is alarming.”
“We are talking about treading into a territory that the genetics community has felt rather strongly is still research,” Collins said. “Unanimously, the professional genetics community, the Human Genome Council and the National Breast Cancer Coalition have stated that these tests should not now be made available.”
But Fred C. Follmer, chief finan cial officer of the Preferred Oncology Network in Atlanta, a national association of hundreds of private cancer specialists, said the critics “had better get ready for this.”
The tests, he said, already are here. His group has signed an agreement with OncorMed Inc., a biotechnology company in Gaithersberg, Md., which will perform the tests. OncorMed also has advertised to doctors outside the network that it now can test patients for cancer genes.
Members of the oncology network will begin offering the tests within the next month.
Dr. Timothy Triche, chief executive officer at OncorMed and chief of pathology at Children’s Hospital in Los Angeles, said he recognizes the controversy but it is too late to stop the testing.
Triche says he expects it will not be long before doctors begin using the tests routinely. “With time, of course, this will be available to every physician,” he said.
He said the tests can help cut medical costs, which could be useful to health maintenance organizations. “So it is prudent not to try to screen 300,000 but to identify the 10,000 at extreme risk and manage them differently from the others,” Triche said.
Computer programs that OncorMed has developed can help pick out those whose family histories indicate they may carry cancercausing genes, Triche said. Then, those who are identified can be offered genetic tests. If they have inherited cancer genes, the doctors would urge them to be screened for cancer “on a much more regular basis at a much earlier age.”
But some who have done the research leading up to the gene discoveries are wary.
Dr. Barbara Weber, a breast cancer researcher at the University of Pennsylvania School of Medicine, said she regularly gets calls from women and their doctors asking for the breast cancer gene test.
One problem, she and others say, is that the gene, called BRCA1, is large with many possible mutations. If investigators find a mutation they have not seen before, they cannot tell immediately whether that mutation causes cancer.
If they do not find any mutations, they still cannot be completely reassuring because the woman may have a mutation in a second recently discovered breast cancer gene or she may have a mutation in a breast cancer gene that is still undiscovered.
And even if the investigators can say for sure that a woman has a mutation that will give her an 80 percent chance of developing breast cancer and a 60 percent chance of developing ovarian cancer, they cannot tell her what to do to protect herself.
Then there is the potential problem of discrimination by health and life insurance companies and by employers when people test positive for a cancer gene.
“You’ve got information that can affect the outcome of people’s lives,” said Dr. Gail Vance, a molecular geneticist at the Indiana University School of Medicine.
“If you go to look for a job at age 40 and you have the breast cancer gene, you know that by age 50 half the women with the gene will have cancer. What does that mean to an employer?”
On the other hand, she added, as many as 15 percent of women with the gene never will get cancer. So, she said, “you may be discriminating against someone who will never get the disease.”
There also is the delicate question of testing children.
OncorMed, in a letter on melanoma testing which it sent to dermatologists throughout the country, wrote, “Early screening with this easy and painless test is particularly useful when testing children.”
But many ethicists and cancer specialists say they worry about testing children and labeling them “cancer-prone” when there is little to be done to protect them from the disease.
The answer, for now, say those who want to go slow, is to offer the genetic tests only in research settings where patients would see expert genetic counselors before being tested and after learning the results.
“Everybody has to be careful,” Weber said. “People tend to say, ‘What’s the big deal? We tell people all the time that they have cancer.”’
But, she added, “This is telling people that they are going to get cancer. This is telling people that their kids will get cancer because of the gene they gave them.”