If you had cancer and you could avoid chemotherapy without risking your long-term health, you would.
Thanks to genomic tests that either predict the effectiveness of chemo or evaluate the risk of getting cancer again, doctors are able to advise patients with certain types of early-stage breast cancer to forgo chemo.
Similar tests for colon and prostate cancers either recently became available or will be out soon, and tests for other cancers are being developed.
“Looking at the biology of the tumor, for most cancers, it will be the standard of care in five years,” said Dr. Jim Edney, a surgical oncologist and professor at the University of Nebraska Medical Center. “For breast cancer, it's clearly right there.”
An industry analyst said such tests are a big part of the future of medicine.
“Within the broader health care economic discussion, there is a lot of talk about not only safety and efficacy, but also cost-effectiveness,” said Matt Dolan, a senior research analyst at Roth Capital Partners. “These types of tests check all those boxes.”
One of the breast cancer tests, the MammaPrint, was recently validated by a study in which 97 percent of the women who were identified by the test as low risk for breast cancer recurrence — and who chose not to have chemo — were cancer-free five years later.
Another, more commonly used test, the Oncotype DX, has been evaluated in 14 clinical studies involving more than 4,000 breast cancer patients worldwide, including a large validation study whose findings have appeared in the New England Journal of Medicine.
One focus of diagnostic companies, Dolan said, is to apply genomic sequencing, which is much more complicated than the process employed by the existing tests. That would allow doctors to detect genetic variants that could be related to disease.
“As the price of sequencing an entire genome goes down per individual,” he said, “it becomes more economically feasible for these broader panels to be run on patients.”
Genome sequencing costs have already plummeted over the past decade. What cost $100 million in 2001 cost less than $10,000 in 2012, the National Human Genome Research Institute says.
Genomic testing has its roots in the Human Genome Project, a $2.7 billion, 13-year effort started in 1990 to identify the 20,000 to 25,000 genes in human DNA. The first funding for the project was part of the Reagan administration's 1987 budget recommendation — a jump-start not unlike the $100 million proposal for a brain-mapping initiative that President Barack Obama announced last week.
So far, a broad look at a person's genome has limited value in the clinic, said Warren Sanger, the director of the human genetics laboratories at UNMC. “The major effort in this high-volume sequencing is interpreting what they find,” he said. “You'll find hundreds of mutations in everybody. What's important in a patient is very time-consuming (to determine) and not really an exact science overall at this point.”
What's more useful for cancer patients, Sanger said, is sequencing up to 100 genes at one time that are known to be important in cancer.
Researchers from the company that makes the most-used breast cancer test, Genomic Health, first identified 250 genes that could be associated with the behavior of breast cancer tumors from among the tens of thousands of genes in the human genome. They then narrowed the list to 16 genes that showed a strong and consistent statistical link to breast cancer that has spread to another part of the body, plus an additional five reference genes.
Results of the company's Oncotype DX test are reported as a number between 0 and 100, with a lower score meaning the cancer has less chance of returning and a higher score suggesting a greater chance of recurrence.
The score also helps patients and doctors decide on the potential benefit of adding chemotherapy to hormonal therapy. A low score indicates that the patient will receive minimal benefit from chemo, while a high score indicates a significant benefit.
The MammaPrint test, from a company called Agendia, looks at 70 genes to suggest how the cancer will progress and indicate whether the risk of cancer recurrence is low or high.
“This is the most exciting area, I think, in medicine today,” said Doug Bradley, an Agendia spokesman. “Traditionally, chemotherapy patients were a 'one size fits all.' But chemotherapy only works in 10 to 15 percent of the cases.”
Before these tests, he said, physicians followed guidelines that recommended chemo in most cases.
Doctors also assess a patient's age, tumor size and grade, and lymph node status before making a recommendation for or against chemo, which employs chemicals to kill fast-growing cells and has side effects such as nausea, hair loss and organ damage.
“Chemotherapy is no day at the beach. It's very disruptive,” said Edney, the UNMC professor.
Dr. Margaret Block, a medical oncologist at Nebraska Cancer Specialists, said, “We're offering chemotherapy to a lot less women now because of these gene tests.”
The MammaPrint test can be used for women with all types of early stage breast cancer, meaning cancer that may have spread to nearby lymph nodes but not to distant parts of the body.
The Oncotype DX test helps identify which women with early stage breast cancer whose cancer is estrogen-receptor-positive are more likely to benefit from adding chemo to their hormonal treatment. That represents about half of breast cancer patients, said Emily Faucette, a Genomic Health spokeswoman.
Doctors can order whichever test they prefer. Edney said he prefers the MammaPrint. Block said she uses Oncotype DX.
A favorable result on one of the tests “doesn't guarantee the patient won't have a relapse, but you can tell them there's a very low chance, therefore, it doesn't make sense” to have chemo, Block said.
Trish Swaink, one of Block's patients, avoided chemo, thanks in part to a score of 13 on the Oncotype DX test. The test confirmed her doctor's preliminary assessment that chemo wouldn't be necessary after a lumpectomy in which a 1.2-centimeter tumor was removed from her breast.
The test result allowed Swaink, 51, to breathe “a sigh of relief,” she said. “I was very nervous about the possibility of having to do chemo. I didn't know a lot about breast cancer, but I just know that chemotherapy is sickness, (being) tired, losing your hair.”
Swaink still must finish radiation treatment and undergo hormone therapy, but she is happy to avoid the cost and discomfort of chemo.
Betty Middendorf, a 49-year-old patient of Edney's, had the MammaPrint test, also after a lumpectomy, which removes a tumor in the breast instead of the entire breast, as a mastectomy does.
“For me, the MammaPrint was the final piece of information that said the cancer is very unlikely to come back,” she said, “but more importantly that I did not need to go through chemotherapy.”
The tests cost about $4,000 each. Oncotype DX is widely reimbursed by insurance companies, Faucette said. MammaPrint is reimbursed by Medicare and some insurers; but if an insurer denies payment for the test and Agendia appeals unsuccessfully, the company will work out a payment program with the patient.
“If they end up with a favorable score, this is a very cost-effective test,” said Dr. Jim Reilly, a surgical oncologist at Methodist Hospital who uses the Oncotype DX but says both are very good tests.
“You can avoid all the trouble and cost of the chemotherapy, and for the insurance companies, that's very favorable, too.”
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