EORTC study published in NEJM helps curb treatment in early-stage breast cancer, improve quality of life

The MINDACT study, managed by EORTC in partnership with BIG (Breast International Group), estimated that compared to traditional methods of evaluation, genome testing could help identify an additional 14% of women with early-stage breast cancer who could safely be spared post-surgery chemotherapy.

The research examined how using genome testing along with clinical evaluation among women with operable, invasive breast cancer and 0-3 positive lymph nodes, could improve evaluating their risk of experiencing metastasis post-surgery.

Using two sets of tests, – a clinical evaluation called Adjuvant! Online and a 70-gene signature called MammaPrint – patients were rated as “high-” or “low-”risk. When both results came back “high”, the patients were treated with post-surgery chemotherapy. When both results were “low”, they did not receive chemotherapy. Those women whose two tests differed (one “high” and one “low”) were randomized into two groups; one receiving chemotherapy, the other not.  Five-year follow-up of those two groups showed   chemotherapy provided little to no benefit to women with at least one “low” test result for metastasis-free survival. In fact, using the 70-gene test, the MINDACT results demonstrated that 46% of women with early-stage breast cancer currently prescribed a course of adjuvant chemotherapy could consider foregoing this additional treatment, therefore avoiding its serious side-effects, with no difference in outcome.

“The MINDACT study is quite unconventional, and represented a bit of a leap of faith for participating patients and clinicians,” says Jan Bogaerts, EORTC Director of Methodology. “When the option is between “treat” and “don’t treat”, the choice is much harder to make, and trials investigating such a question are notoriously difficult to complete. The fact that 6,700 women and their doctors were willing to help test whether chemotherapy treatment can be scaled down says a lot about the need to explore treatment options that are better aligned with the actual risk for the patient.”

MINDACT is a multi-center, multi-group collaboration which acts as a great example of public-private partnership with the involvement of academic research groups, industry, patient organisations and European funding. The first prospective translational research study in breast cancer of this magnitude in Europe, MINDACT involved 112 hospitals in nine countries, with 11,000 patients screened and nearly 6,700 recruited. Its success demonstrates the value of cross-discipline, international, multi-stakeholder collaborations in implementing broad-reaching trials that can bring a concrete benefit to cancer patients’ quality of life.

In an accompanying NEJM editorial, Drs Clifford A. Hudis, CEO of the American Society of Clinical Oncology, and Maura Dickler, of the Memorial Sloan Kettering Cancer Center said: “The MINDACT trial shows how a well-coordinated and highly collaborative multinational team of investigators can efficiently conduct a potentially practice-changing study. This is a research model that will be even more critical as we advance toward precision medicine.”

“These findings help establish better-informed tradeoffs for women with early-stage breast cancer deciding whether or not to undergo chemotherapy, and can spare many of these women the unnecessary hardship of going through this additional toxic treatment when its efficacy is very limited,” said Fatima Cardoso, Principal Investigator for the study and head of EORTC’s Breast Cancer research group.

MINDACT also contributes to the advancement of precision medicine through the integration of a biobank and samples system, which will enable continuous learning and the potential development of new treatment options.  Additional follow-up of study participants will continue in the coming years.

The MINDACT study was partially funded by a European Commission grant within its 6th research framework program.