Some breast cancer patients may safely forgo chemotherapy

June 15, 2023 — Sometimes less can be more, and researchers are increasingly looking for ways cancer treatment can be safely “mitigated,” making a patient’s care less aggressive without affecting their odds of survival. One new study showed that women with HER2-positive early breast cancer were able to be treated successfully without Thus, chemotherapy avoided its harsh side effects.

HER2-positive breast cancer is not common, and is diagnosed in about 1 in 5 women with breast cancer. This means that cancer cells have extra copies of the gene that produces the HER2 protein, and this type of cancer tends to be more aggressive than others.

But treatment specifically targeting HER2-positive breast cancer has been developed. Trastuzumab and pertuzumab target the HER2 protein, and these two drugs are generally used in combination with conventional chemotherapy before and after surgery.

However, the current study, presented recently at the annual meeting of the American Society of Clinical Oncology in Chicago, showed that some women can forgo chemotherapy.

All patients in the study responded to treatment very well. About 95% of patients remained cancer-free after 3 years, and this number was even higher in the group that did not receive chemotherapy. Curtis noted that for those 30 percent of patients, who were essentially 1 in 3 patients who didn’t receive chemotherapy, the three-year survival without cancer relapse was excellent, at about 99 percent.

“In my view, this study may identify the 30% of patients who may be cured without the need for chemotherapy and treated only with a combination of trastuzumab and pertuzumab and endocrine therapy, if appropriate,” Curtis said.

He noted that the rate of serious side effects was much lower in patients who were able to avoid chemotherapy.

“What we saw in this trial is that there was clearly a benefit in terms of adverse events,” said Justin M. Balko, MD, of Vanderbilt University Medical Center in Nashville, Tennessee, who commented on the study during the meeting. “As someone who studies immune-related adverse events in my own laboratory, I thought that while this was unexpected, it was really useful to see the data on how likely the quality of life is for those patients who are saved or spared from chemotherapy.”