After surgery, some cancer patients can safely skip radiation or chemotherapy, and two studies have shown shorter, softer care for cancer.
Researchers are looking for ways to predict which type of cancer is being diagnosed Unnecessary treatment can be avoided to reduce harmful side effects and unnecessary costs.
A new study used blood tests to determine if patients with colon cancer could skip chemotherapy after surgery. Another danger suggests that some breast cancer patients may miss radiation after lumpectomy.
The study was discussed at the annual meeting of the American Society of Clinical Oncology, which ended Tuesday in Chicago. A study on colon cancer, funded by the Australian and U.S. governments and nonprofits, was published Saturday in the New England Journal of Medicine.
The research will allow doctors to “focus on patients who think they really benefit from chemotherapy and avoid side effects for patients who don’t need it,” the doctor said. Stacey Cohen of the Fred Hutchinson Cancer Center in Seattle reviewed the results of colon cancer and did not participate in the study.
Although many patients with colon cancer recover, chemotherapy is given after surgery. Medications can come with side effects such as dizziness, anemia and memory problems.
However, it was difficult to determine which patients might not require further treatment. Researchers have examined blood tests to see if they can help doctors.
The study involved 455 patients who underwent surgery for cancer that had spread to the colon wall. After the operation, many received a blood test adapted to the genetic profile of the tumor to identify the remaining bits of cancer DNA.
Their care was guided by a blood test: if it showed no signs of remaining cancer, the patients did not receive chemotherapy. At the same time, doctors made chemical decisions for the remaining patients in the usual way, guided by the analysis of tumors and nearby tissues.
Fewer patients in the blood test group received chemotherapy – against 15%. 28%. But about 93% of the two groups still have cancer after two years. In other words, the blood test group was equally good with less chemotherapy.
“Patients whose cancer DNA has not been detected after surgery have a very low chance of recurrence of cancer, indicating that chemotherapy is of little benefit to these patients,” he said. The study was led by Jeanne Tie of the Peter McCallum Cancer Center in Melbourne, Australia.
The omission of chemotherapy “makes a big difference in a person’s quality of life if it is done without the risk of recurrence,” said ASCO President Dr. Everett Vokes specializes in head, neck and lung cancer at the Medical University of Chicago.
Another study followed 500 older women with low levels of a protein called Ki67, a common form of early-stage breast cancer and a sign of rapid-growing cancer.
After the operation, the women took hormone-blocking pills, the standard treatment for this type of cancer, but they did not receive radiation treatment.
Five years later, 10 women were diagnosed with recurrence of breast cancer, and one died of breast cancer. There are no comparison groups, but the researchers say the results are better than historical data for similar patients who have been exposed to radiation.
“We believe that the benefits of radiation will be very small in this population compared to the negative effects,” the doctor said. Timothy Whelan of McMaster University in Hamilton, Ontario, led the study, which was supported by the Canadian Breast Cancer Foundation and the Canadian Cancer Society.
Radiation can cause skin problems, fatigue and often long-term heart disease and secondary cancer.
The study is a “good feeling” statement for patients with low-risk cancer and will help doctors understand which of their patients can “reliably” transfer radiation, the doctor said. Deborah Axelrod did not participate in the NYU Langone Health study.
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