ASCO: Agendia test spots ultralow breast cancer recurrence risks, flagging women who could skip chemo

DNA helix forming inside a test tube
The analysis presented at ASCO focused on 1,000 women with an ultra-low score, who had nearly 100% survival after eight years with only five years of anti-estrogen therapy. In addition, almost all 157 participants who received no systemic therapy went metastasis-free. (Getty Images)

Breast cancer test maker Agendia has delivered new data showing its MammaPrint genomic diagnostic can help identify patients at an ultralow risk of recurrence, including some who are likely to keep cancer at bay for at least 20 years. 

This information, culled from an analysis of 70 different genes, could help oncologists tailor treatment plans for certain early-stage breast cancer cases, as well as better manage the side effects of chemotherapy over the long term.

The independent phase 3 study, presented at the annual meeting of the American Society of Clinical Oncology, found that more than 99% of breast cancer patients in this category survived at least eight years, regardless of other clinical risks—while 97% saw no distant tumor metastases over the same amount of time.

“The Ultra Low threshold identifies patients who may be candidates for further de-escalation of treatment,” said lead author Josephine Lopes Cardozo, a researcher at the Netherlands Cancer Institute and a fellow of the European Organization for Research and Treatment of Cancer, which sponsored the trial.

The wider study, published earlier this year in The Lancet Oncology, enrolled nearly 7,000 patients with newly diagnosed breast cancer. After a median follow-up of nearly nine years, 46% of patients shown to be at a clinically high risk for recurrence—but who had a low-risk result from the MammaPrint test—were able to skip chemotherapy entirely without hurting their outcome.

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“To give the patient’s care team this kind of prognostic insight at the time of diagnosis will hopefully allow for many patients to avoid over-treatment and further reduce the risk of side effects while maintaining excellent survival,” Lopes Cardozo said in a statement

The analysis presented at ASCO focused on 1,000 women with an ultralow score. They posted nearly 100% survival after eight years with only five years of anti-estrogen therapy. Plus, almost all 157 participants who received no systemic therapy went metastasis-free.

This prognostic information could assist in the "management of endocrine therapy, particularly for those women experiencing severe side effects, and struggling to remain on their prescribed treatment,” said Agendia’s chief medical officer, William Audeh, M.D.

At the same time, Agendia presented data from a separate, retrospective study showing the MammaPrint test could help identify a cohort of breast cancer patients who were most likely to benefit from extended letrozole endocrine therapy. These patients had significantly better rates of distant recurrence, disease-free survival and breast cancer-free periods. 

“By stratifying patients beyond High or Low Risk, we are able to see a larger breadth of difference in genomic signatures,” said study researcher Adam Brufsky, M.D., Ph.D., co-director of the Women’s Cancer Center at UPMC Hillman Cancer Center.

“More granular information such as this allows us to better understand the biology of a tumor and gets us closer to ensuring that each patient receives the data she needs to have informed discussions with her physician to decide on the best treatment path, even years after her initial treatment,” Brufsky said.