KeepHealthCare.ORG – Do All Women With Breast Cancer Need Chemotherapy?
Chemotherapy, long a mainstay of early breast cancer treatment, is being used less and less as oncologists and women increasingly turn to genomic profiling to see who is likely to benefit from such a drug regimen, according to a study published online on December 11, 2017, in the Journal of the National Cancer Institute.
There’s “no major change in the evidence or practice guidelines,” says Allison Kurian, MD, the lead author of the study and an associate professor of medicine and health research and policy at Stanford University in Palo Alto, California. But genomic profiling helps identify women with hormone-responsive (tumors that grow in response to hormones) early breast cancer who can safely skip chemotherapy. Clinicians, says Dr. Kurian, appear to be trying to take advantage of profiling to pull back on the toxicity that patients are exposed to.
“This seems to reflect a broader change in the culture toward precision medicine,” says Kurian. Dawn Hershman, MD, a professor of medicine and epidemiology at Columbia University Medical Center in New York City, who was not involved in the study, agrees. “This probably reflects global trends,” she says. “As we get better and better tests, we can use less chemotherapy. Genomic tests were developed to personalize care.”
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Study Reveals Quick and Clear Trend Toward Less Chemo
The study relied on population-based data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results registry to study chemotherapy use in a total of 5,080 women who lived in Los Angeles County and Georgia.
Reviewing data between 2013 and 2015, investigators found that, in 2015, 21.3 percent of women with early breast cancer received chemotherapy compared with 34.5 percent in 2013. At the same time, oncologists recommended chemotherapy less, with 31.6 percent suggesting it in 2015 compared with 44.9 percent in 2013.
For women in whom the cancer had spread beyond the initial tumor and into surrounding lymph nodes, 14.1 percent received chemotherapy in 2015 compared with 26.6 percent in 2013. Women with lymph node involvement also got chemotherapy less frequently, with use dropping from 81.1 percent in 2013 to 64.2 percent in 2015.
The study further revealed that genomic profiling was ordered by more than two-thirds of oncologists if a woman disagreed with her doctor’s recommendation for chemotherapy.
In addition, one-third of the decline in chemotherapy for node-positive cancers was attributed to gene testing, an especially striking finding. This represents a marked change in practice. Before these tests were available, these patients would have been advised to get chemotherapy. Genetic testing did not increase for node-negative cancers.
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Two Studies May Reveal How Good Genomic Profiling Guidance Proves to Be
Both Kurian and Dr. Hershman say that they would like to see more evidence on long-term outcomes for women who use genomic profiling and skip chemotherapy as part of their regimen in response to its results.
Two studies are currently underway to assess the outcome for women like this. Both rely on a genetic-profiling test called Oncotype DX, which measures the activity of cancer-related genes in tumor tissue. Patients receive a score between 0 and 100; a low score means the cancer has a low chance of recurring and the patient is less likely to require chemotherapy.
The RxPONDER phase 3 trial is evaluating the use of genomic profiling in deciding whether to undergo chemotherapy in women who have breast cancer and have one to three positive lymph nodes, are receiving hormonal therapy, and received an Oncotype DX score of 25 or less.
A separate phase 3 trial, TAILORx, aims to see whether hormone therapy alone or in combination with chemotherapy is best for women with lymph node-negative, estrogen-receptor positive breast cancer who received an Oncotype DX score between 11 and 25. More than 10,000 women are enrolled in the trial.