Some cancer patients can skip treatment, two studies show

After surgery, some cancer patients can safely skip radiation therapy or chemotherapy, according to two studies investigating shorter and milder cancer treatments.

Researchers are looking for ways to accurately predict which cancer patients can avoid unnecessary treatment and reduce adverse side effects and unnecessary costs.

A new study used blood tests to determine which colon cancer patients could skip chemotherapy after surgery. Others suggest that some low-risk breast cancer patients can omit radiation after breast mass removal.

This study was discussed at the American Society of Clinical Oncology’s annual meeting in Chicago on Tuesday. A colon cancer study funded by Australian and US governments and nonprofits was published by the New England Journal of Medicine on Saturday.

According to the findings, doctors can “focus on patients who really benefit from chemotherapy and avoid side effects in patients who don’t seem to need it,” said Stacey Cohen of the Fred Hutchinson Cancer Center in Seattle, who reviewed colon cancer. The doctor said. He was not involved in the findings and research.

Colon cancer

Many people with colorectal cancer receive chemotherapy after surgery, even if it may be cured. The drug may have side effects such as nausea, anemia, and memory loss.

However, it is difficult to identify which patients may not require further treatment. Scientists have studied whether blood tests can help doctors call.

The study enrolled 455 patients who underwent surgery because the cancer had spread to the colon wall. After surgery, one group underwent a blood test customized to the tumor’s genetic profile to detect the rest of the cancer’s DNA.

Their care was guided by a blood test: if it showed no signs of remaining cancer, the patient did not receive chemotherapy. Meanwhile, doctors made chemotherapy decisions for the remaining patients in the usual way, based on analysis of the tumor and nearby tissue.

Fewer patients in the blood test group received chemotherapy — 15% vs. 28%. However, about 93% of both groups were still cancer-free after two years. In other words, the blood test group worked just as well with less chemotherapy.

“In patients whose cancer DNA is not detected after surgery, the chances of cancer recurrence are very low, suggesting that chemotherapy is very unlikely to benefit these patients,” Melbourne, Australia. Dr. Jeanne Thai of the Peter McCallum Cancer Center in Melbourne said. He led the study.

Dr. Everett Borks, president of ASCO, which specializes in head and neck and lung cancer at the University of Chicago, said by skipping chemotherapy, “If we can do that without risk of recurrence, we will improve our quality of life. It makes a big difference. ” medicine.

Breast cancer

Another study followed a common form of early-stage breast cancer and 500 older women with low levels of a protein known as Ki67, a marker of fast-growing cancer.

After surgery, women took hormone blockers, the standard treatment for this type of cancer, but did not receive radiation therapy.

Five years later, 10 women saw the cancer relapse in the same breast and one died of breast cancer. There was no comparison group, but the researchers said the results were comparable to historical data from similar patients exposed to radiation.

Dr. Timothy Weeran of McMaster University in Hamilton, Ontario, who led the study with the support of the Canadian Breast Cancer Foundation and the Canadian Breast Cancer Foundation, said: Canadian Cancer Society.

Radiation can cause skin problems, malaise, and, rarely, long-term heart problems and secondary cancers.

This study is a “pleasant” message for patients with low-risk tumors and helps doctors understand which patients can “comfortably and confidently” eliminate radiation. I am involved in research.

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The Associated Press’s Department of Health Sciences is supported by the Science Education Department of the Howard Hughes Medical Institute. AP is solely responsible for all content.