After surgery, some cancer patients can safely skip radiation or chemotherapy, according to two studies that explore a shorter, softer cure for cancer.
Researchers are looking for ways to accurately predict which cancer patients can avoid unnecessary treatment to reduce harmful side effects and unnecessary costs.
A new study used a blood test to determine which patients with colon cancer might skip chemotherapy after surgery. Another suggests that some low-risk breast cancer patients may omit radiation after tumorectomy.
The investigation was discussed at the annual meeting of the American Society of Clinical Oncology, which ended Tuesday in Chicago. The colon cancer study, funded by Australian and U.S. governments and nonprofit groups, was published Saturday in the New England Journal of Medicine.
The findings could allow doctors to “focus on patients who we believe will really benefit from chemotherapy and avoid side effects for patients who probably don’t need it,” said Dr. Stacey Cohen of the Fred Hutchinson Cancer Center. of Seattle, who reviewed colon cancer. findings and did not participate in the investigation.
COLON CANCER
Many patients with colon cancer receive chemotherapy after surgery, even if they can be cured. Drugs can have side effects such as nausea, anemia, and memory problems.
But identifying which patients may not need additional treatment has been tricky. Scientists studied whether a blood test could help doctors make the call.
The study included 455 patients who were operated on because the cancer had spread to the colon wall. After surgery, one group received a blood test, customized according to the genetic profile of their tumor, to detect the remaining DNA fragments from the cancer.
Her care was guided by blood tests: if she showed no signs of remaining cancer, patients would not receive chemotherapy. Meanwhile, doctors made chemotherapy decisions for the rest of the patients in the usual way, guided by the analysis of the tumor and nearby tissue.
Fewer patients in the blood test group received chemotherapy: 15% versus 28%. But about 93% of the two groups were still cancer-free after two years. In other words, the blood test group did just as well with less chemotherapy.
“In patients where cancer DNA is not detected after surgery, the chance of cancer relapse is very low, suggesting that chemotherapy is very unlikely to benefit these patients,” said Dr. Jeanne Tie of Peter MacCallum Cancer Center in Melbourne, Australia, who led the research.
Skipping chemotherapy means “a big difference in a person’s quality of life if it can be done without jeopardizing recurrence,” said ASCO President Dr. Everett Vokes, who specializes in head, neck and lung cancer at the University of Chicago. Medication.
LUNG CANCER
The other study followed 500 older women with a common form of early-stage breast cancer and low levels of a protein known as Ki67, a marker of fast-growing cancer.
After surgery, the women took hormone-blocking pills, a standard treatment for this type of cancer, but did not receive radiation treatment.
After five years, 10 of the women saw the cancer return to the same breast and there was a death from breast cancer. There was no comparison group, but the researchers said the results compare favorably with historical data from similar patients who had radiation.
“We estimate that the benefits of radiation would be very small in this population compared to the side effects,” said Dr. Timothy Whelan of McMaster University in Hamilton, Ontario, who led the study, which was supported. of the Canadian Breast Cancer Foundation and the Canadian Cancer Society.
Radiation can cause skin problems, fatigue, and less often, long-term heart problems and second cancer.
The study is a message of “feeling good” for patients with low-risk tumors and will help doctors understand which of their patients “can omit radiation comfortably and confidently,” said NYU Dr. Deborah Axelrod Langone Health, which was not involved in the investigation.
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