Genomic test may tell if adjuvant chemotherapy is right option or not

Advanced breast cancer is an incurable in majority of cases and life expectancy is low for survivors. Adjuvant therapies are prescribed to many women with early-stage disease to eradicating micrometastases that is uncertain to happen. The results of randomized phase 3 MINDACT trial presented at the American Association for Cancer Research Annual Meeting claimed that genomic test can assist predicting the patients with early-stage breast cancer who will be most benefited from adjuvant chemotherapy.

The findings of the study recommend who should go for the therapy to receive benefits and those who will not be benefited by the same. The adjuvant chemotherapy could lead to long-term health risks. Thus there is need to consider both potential survival benefit and potential for long-term risks such as secondary cancers, cardiac toxicity and reduced cognitive function.

The MINDACT trail was conducted at 111 centers in nine European countries. A total of 6,693 women of the median age, 55 years as part of the trail underwent surgery for early-stage breast cancer from 2007 to 2011. The majority had stage T1 (58%), node-negative (80%), hormone receptor-positive (88%), HER-2–negative (90%) disease.

The results were observed using MammaPrint analysis of tumor tissue and an online tool that counts reoccurrence rate based on common clinical and biological criteria. There were 2,745 participants who were with low risk for recurrence on receiving no adjuvant chemotherapy, while 1,806 participants were said to have at high risk for recurrence on receiving adjuvant chemotherapy.

“This trial has played a major educational role … and popularized the concept of biology-driven treatment. It demonstrated that genomics can provide important information in order to treat patients with early breast cancer in a more optimal way,” said researcher Martine Piccart, MD, PhD, head of the medicine department at Jules Bordet Institute in Belgium and co-founder and chair of the Breast International Group.

In a report published by the Philly, “After surgery to remove their tumors, breast cancer patients with a MammaPrint score recommending against chemotherapy had a 95 percent survival rate, said co-researcher Laura van ‘t Veer, the test’s inventor.”

“That’s very high, and we showed that it doesn’t differ between those who are treated and those who are not treated by chemotherapy,” said van ‘t Veer, leader of the breast oncology program at the University of California, San Francisco Diller Family Cancer Center.

According to a report in OncLive by Wayne Kuznar, “A 70-gene signature (MammaPrint) demonstrated a high level of accuracy at identifying a large subset of women with clinically high-risk early stage breast cancer for whom adjuvant chemotherapy was unlikely to produce benefit, according to findings from a phase III trial presented at the AACR Annual Meeting 2016.”

In the study known as MINDACT, patients deemed high risk clinically but low risk by the gene signature had a similar 5-year rate of distant metastasis-free survival (DMFS) whether randomized to adjuvant chemotherapy or not, said Martine Piccart, MD, PhD. “The important message here is among the clinically high-risk patients, the clinical use of MammaPrint is associated with almost a halving of the use of chemotherapy,” she said

“The trial was not powered to answer the question of whether adjuvant chemotherapy benefits women with discordant risk assessments, Piccart said. However, an intent-to-treat analysis showed little separation in distant metastasis-free survival curves in these groups based on chemotherapy receipt,” according to a news report published by Healio.

“A statistician will tell you … it is not totally impossible that there is a very small chemotherapy benefit,” Piccart said. “However, the relative reduction in risk … would translate to a very small absolute benefit that would not justify the risks of chemotherapy.”

“This trial has played a major educational role … and popularized the concept of biology-driven treatment,” Piccart said. “It demonstrated that genomics can provide important information in order to treat patients with early breast cancer in a more optimal way.”

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