DAVID GREENE, HOST:
We've been looking at some new research in the medical journal JAMA Oncology. It finds that women with early-stage, low-risk breast cancer may be able to skip follow-up treatments like hormone therapy and radiation after they have had surgery to remove the cancer. Here's NPR's Patti Neighmond.
PATTI NEIGHMOND, BYLINE: For years, doctors have known there are big differences in breast cancers. Some are aggressive and life-threatening. Others are not. Breast cancer surgeon Laura Esserman.
LAURA ESSERMAN: But if you can't identify them, and you can't tell which is which, you give everyone the treatment because you're afraid to miss somebody.
NEIGHMOND: So after diagnosis, most patients have surgery, often followed by radiation chemotherapy or hormone therapy. Side effects can be severe. Esserman, a cancer researcher at the University of California, San Francisco, teamed up with Swedish doctors to look at how a test which biologically measures a tumor's aggression might identify patients at low risk of having cancer return. The test worked, and Esserman was able to pinpoint patients at very low risk of having cancer return even up to 20 years after diagnosis.
ESSERMAN: You can really say to someone, you're not going to die of this disease. And we don't have to be aggressive up front and treat you with everything just in case.
NEIGHMOND: Esserman looked at medical records from 652 Swedish patients who had a mastectomy or lumpectomy plus radiation. The tumor test found that 15 percent of them were classified as ultra-low-risk tumors. About half of the women got no further their treatment. About half got the hormone blocker tamoxifen. After 20 years, nearly all were still alive. The results build on findings from a 2016 study that showed nearly half of women with low-risk cancer could actually skip chemotherapy and not have their cancer return.
ESSERMAN: This ultra-low-risk designation really identifies people with an extremely low risk for recurrence or death from breast cancer. And so that means that, up front, we can say, you don't need all that treatment. It's a great thing to be able to tell people.
NEIGHMOND: Esserman says it now appears about 20 to 25 percent of breast cancer tumors diagnosed today aren't ever going to cause problems and don't need treatment after surgery. Dr. Len Lichtenfeld with the American Cancer Society says the findings concur with growing evidence in many different cancers.
LEN LICHTENFELD: This study shows us that biology matters. And that's an evolving theme that has been talked about for several years in cancer care.
NEIGHMOND: Using science, he says, to understand that, sometimes, less treatment is highly effective.
LICHTENFELD: We used to think that every cancer we found was a bad cancer. And we used to think that every cancer we found had to be treated aggressively. It's taken a long time for us to begin to understand and adopt those principles that we can treat less and still be effective.
NEIGHMOND: The tumor test researchers used is called MammaPrint. It's a genomic test that looks at a set of 70 genes and a tumor which control production of proteins that drive the tumor's growth. It costs about $4,000 and is sometimes covered by insurance. It measures how genes are functioning and differs from genetic tests that determine someone's hereditary risk of cancer. Patti Neighmond, NPR News.
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