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The largest cancer precision medicine trial ever completed has revealed that thousands of women with a common type of breast cancer will no longer need chemotherapy.
Using a genetic test that’s been around since 2004, the researchers behind the study, just published in the New England Journal of Medicine, found that some women with breast cancer can probably skip chemo without hurting their chances of surviving the disease.
The test, called Oncotype DX, is designed for women with the most common type of breast cancer, which accounts for half of all breast cancer cases in the US: hormone receptor-positive, HER2-negative, and axillary node-negative cancer. It works by helping to predict how likely it is that a woman’s breast cancer will come back on a scale of 0 to 100, based on reading a sample of tumor tissue.
Doctors have long known that women with a score of 0 to 10 are considered to have a very low chance of breast cancer recurrence and are not likely to benefit from chemo. Women with scores of 26 to 100 are considered good candidates for chemo.
But most women fall in the middle 11-to-25 range, and it’s been unclear what to do for this group.
The new study, called the Trial Assigning Individualized Options for Treatment (TAILORx), was designed to fill in this gap. And it was funded, in part, by the National Cancer Institute using proceeds from the US Postal Service’s breast cancer stamp.
The takeaway from the study is clear, the lead author, Dr. Joseph Sparano of the Montefiore Medical Center in New York, told me: “We can now approach breast cancer therapy in this population with an unprecedented level of precision and evidence to make informed treatment recommendations of who is most likely to benefit [from chemotherapy] and who is not likely to need it.”
That matters because chemotherapy, which is meant to kill fast-growing cancer cells, can also kill healthy cells. Along with the well-known side effects, the drugs can damage the heart, kidneys, bladder, lungs, and nervous system. This new study could help thousands of women avoid that pain, discomfort, and harm.
Some 70 percent of women diagnosed with the most common type of breast cancer may be able to skip chemo
The study involved more than 10,000 women with breast cancer and followed them for nearly a decade, which should give us confidence in the results. Most — six in 10 — had that middle-range recurrence score of between 11 and 25. The women with this group were randomly assigned to get either hormone therapy or a combination of hormone therapy and chemotherapy.
They were then followed for nine years — an eternity in a clinical trial of this size. At that point, the survival rates in the two groups looked indistinguishable: Nine in 10 of the women who didn’t get chemo were still alive, as were nine in 10 of the women who got chemo.
“Many of the women in that 11-to-25 range would say, ‘I want to do everything to keep the cancer from coming back,’ so they’d get the chemo,” said Otis Brawley, chief medical and scientific officer for the American Cancer Society. “What this study does is clear up that gray area from 11 to 25.”
There was one group that had a slightly different response: For reasons the researchers don’t yet understand, women age 50 and younger who had a recurrence score of 16 to 25 seemed to gain some benefit from chemo. So that means doctors may need to consider a woman’s age in their decision whether to recommend chemo, Brawley said.
Still, the study results indicate that women over 50 who have a score of 25 or below, and the women under 50 with a score of 16 or below, can consider skipping chemo. And that’s a lot of treatment that can be avoided, according to Sparano: The results suggest some 70 percent of women who are eligible for the Oncotype DX test can probably go without chemo.
Avoiding chemo means avoiding months of treatment and horrendous side effects
For some patients, these results will be a game changer because of how difficult and even deadly the chemo they otherwise would have gotten can be.
There are different types of chemotherapy drugs, and depending on the stage of breast cancer, they’re given either before or after a surgery to remove the tumor, according to the American Cancer Society. Chemo for breast cancer is typically given by injection or through an infusion that can take hours. Doctors schedule these treatments over the course of several months, depending on the stage of cancer, in cycles that involve rest periods.
Because the chemo kills both healthy cells and cancerous ones, the side effects can be treacherous. “I have lost three patients over the last 25 years because they got leukemia from their chemo,” Brawley said. “I have lost patients who got congestive heart failure because of their chemo, and I have seen patients who get ‘chemo brain’ and have difficulty concentrating for the rest of their lives.”
As Joanna Moorhead, an opinion writer in the Guardian and a breast cancer patient, explained, an Oncotype DX test resulted in a much more manageable treatment pathway after her cancer was diagnosed:
I had to cope with only three minor operations, which were all done as day-case surgery — and I didn’t need to take even an aspirin after any of them. Chemotherapy would have made things very different: there would have been months of feeling dreadful, and long periods off work — the very things, in other words, that give illness the power to upend our lives — not to mention hair loss, which many women who have had chemotherapy for breast cancer say is the single worst thing about the whole experience.
“Any effort to define the women who don’t need these drugs is a good one and the reason why I’m so positive about this study,” Brawley said.
The study was funded by postage stamps
Another piece of good news about the study: It was funded, in part, by proceeds from breast cancer stamps. Since the stamp made its first appearance in 1998, it has helped raise more than $86 million for breast cancer research, according to the US Postal Service.
The stamp was also the first in the US to be sold at a surcharge in order to raise funds for a specific cause, the Associated Press reported, and its role in funding the TAILORx was critical:
The National Cancer Institute sponsored the study, along with several foundations. A key part — the initial $4.5 million of the cancer institute’s $36 million contribution — came from the stamp, said Dina Singer, who is involved in the institute’s use of stamp proceeds. The money was used to pay for the gene test, which costs more than $4,000 per person.
Besides helping women avoid toxic, unnecessary, and costly treatments, there’s something else the funding contributed to: it’s the largest precision medicine study ever done in cancer medicine.
The study is the largest precision medicine trial ever done in cancer
Precision medicine — also known as personalized or individualized medicine — has been one of the big, shiny promises in health care that’s so far failed to fully deliver.
The idea is that doctors can use genetic tests to tailor medical treatments to the specific biology of patients. While this is already happening in some corners of health care, there are major gaps in fully realizing the promise of this approach for a broad range of diseases.
One reason why is that we still don’t understand enough about the human genome and how it interacts with our environment to tailor treatments for many maladies. Another is that in the areas where we do have a sufficient amount of information, scientific funders won’t always pay for the kinds of studies to give us definitive answers about which treatments may work best in whom.
TAILORx is a rare exception. “As we learn more about genomics,” Brawley said, “we are starting to realize that there are a number of different kinds of breast cancer, a number of different kinds of lung cancer, and some of those cancers are slow-growing, some may not even grow at all, some of those cancers are fast-growing.”
Studies like TAILORx can help match treatments to people with these different stages of disease — and avoid over- or undertreating cancer.
But we need more research on this scale to do that. “The promise [of precision medicine] is tremendous,” Brawley said. “But the limits we have on cancer research in terms of funding are going to prevent us from realizing all the wonderful things. I can’t name for you another 10,000-person study out there right now.”
