After surgery, some cancer patients can safely skip radiation or chemotherapy, according to two studies exploring shorter, gentler cancer care.
Researchers are looking for ways to accurately predict which cancer patients can avoid unnecessary treatment to reduce harmful side effects and unnecessary costs.
One new study used a blood test to identify colon cancer patients who could skip chemotherapy after surgery. Another suggested that some low-risk breast cancer patients could omit radiation after lumpectomy.
The research was discussed at the annual meeting of the American Society of Clinical Oncology, which concluded Tuesday in Chicago. A study on colon cancer, funded by the Australian and US governments and non-profit groups, was published Saturday in the New England Journal of Medicine.
Dr. Stacey Cohen of the Fred Hutchinson Cancer Center in Seattle, who reviewed colon cancer findings and was not involved in the research, said.
Many colon cancer patients undergo chemotherapy after surgery, although they may be cured. Medications can come with side effects such as nausea, anemia, and memory problems.
But identifying patients who may not need further treatment has been challenging. Scientists studied whether a blood test could help doctors make the call.
The study included 455 patients who underwent surgery because the cancer had spread to the wall of the colon. After surgery, one group received a blood test, customized to the tumor’s genetic profile, to detect any remaining bits of the cancer’s DNA.
Their care was directed by a blood test: if they showed no signs of persistent cancer, the patients did not receive chemotherapy. Meanwhile, doctors made chemotherapy decisions for the rest of the patients in the usual way, guided by analysis of the tumor and nearby tissues.
Fewer patients in the blood test group got chemotherapy – 15% versus 28%. But about 93% of both groups are still cancer-free after two years. In other words, the blood test group performed equally well with less chemotherapy.
“In patients whose cancer DNA is not detected after surgery, the chance of cancer recurring is very low, indicating that chemotherapy is unlikely to benefit these patients,” said Dr. Jane Tay, of the Peter McCallum Cancer Center in Melbourne, Australia. led search.
Skipping chemotherapy makes a “big difference to a person’s quality of life if it can be done without having to put them at risk for recurrence,” said Dr. Everett Fox, president of ASCO, who specializes in head and neck and lung cancer at the University of Chicago. medicine.
The other study followed 500 elderly women with a common type of early-stage breast cancer who had low levels of a protein known as Ki67, a marker of fast-growing cancer.
After the surgery, the women took hormone-blocking pills, a standard treatment for this type of cancer, but they did not receive radiation therapy.
Five years later, 10 of the women had seen a recurrence of cancer in the same breast, and there had been one breast cancer death. There was no comparison group, but the researchers said the results compare favorably with historical data for similar patients exposed to radiation.
Dr. Timothy Whelan of McMaster University in Hamilton, Ontario, who led the study, which was supported by the Canadian Breast Cancer Foundation and the Canadian Cancer Society, said.
Radiation can cause skin problems, fatigue, and, less commonly, long-term heart problems and second cancers.
Dr. Deborah Axelrod of NYU Langone Health, who was also not involved in the research, said.
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Carla K. Johnson, Associated Press