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 precisely predict which cancer patients can avoid unneeded treatment to cut down on harmful side effects and unnecessary costs, per the AP. One new study used a blood test to determine which colon cancer patients could skip chemotherapy after surgery. Another suggests some low-risk breast cancer patients can omit radiation after a lumpectomy. The research was discussed at the annual meeting of the American Society of Clinical Oncology, which wrapped up Tuesday in Chicago.
The colon cancer study, funded by the Australian and US governments and nonprofit groups, was published Saturday by the New England Journal of Medicine. The findings could allow doctors to "focus on the patients we think would truly benefit from chemotherapy and avoid the side effects for patients for whom it's likely unnecessary," said Dr. Stacey Cohen of Fred Hutchinson Cancer Center in Seattle, who reviewed the findings and wasn't involved in the research. The study involved 455 patients who had surgery because cancer had spread into the colon wall. After surgery, one group received a blood test, customized to their tumor's genetic profile, to detect any remaining bits of cancer DNA.
Fewer patients in the blood test group got chemo—15% vs. 28%. But about 93% of both groups were still free of cancer after two years. In other words, the blood test group fared equally well with less chemotherapy. 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 for fast-growing cancer. After surgery, the women took hormone-blocking pills, a standard treatment, but they didn't get radiation. After five years, 10 of the women saw cancer return in the same breast, and there was one breast cancer death. There was no comparison group, but researchers said the results compare favorably to historical data for similar patients who had radiation. (A small study on rectal cancer seems to have cured every patient.)