More research urged to compare and validate genomic tests for patients with early breast cancer

The European Society for Medical Oncology (ESMO) has welcomed preliminary clinical trial results that suggest genomic testing could allow many patients with early breast cancer to safely avoid chemotherapy.

The new trial results[1], reported at the European Cancer Congress 2013 this week, illustrate that more research is urgently needed to compare and validate the growing number of genomic tests becoming available in oncology, ESMO says.

The MINDACT trial is investigating whether a 70-gene profile called MammaPrint can select the right patients for treatment with chemotherapy in addition to surgery and hormone treatment. More than 6600 patients in 9 countries are taking part.

ESMO spokesman Miguel Martin, Head of the Medical Oncology Service, Hospital General Universitario Greogorio Marañón, Madrid, Spain said: "What makes the MINDACT trial noteworthy is that it is the first prospective trial aimed at demonstrating that a significant proportion of breast cancer patients can spare chemotherapy without a detrimental effect on distant relapse-free survival, based on the genomic assessment of risk."

The study shows that the genomic test and standard assessment methods produced different risk assessments for 31% of patients. "This means that almost one out of three patients could change their adjuvant therapy due to genomic testing," Martin said.

Final results from the trial will not be available for several years, he noted. "We must wait until the final results of the MINDACT trial are available to confirm that genomic testing with MammaPrint can help some patients avoid chemotherapy without harm," Martin said.

"However, if the final results of the MINDACT trial are positive, that means that non-therapeutically effective chemotherapy and its side-effects can be avoided in a significant proportion of patients."

MammaPrint is one of several genetic tests being evaluated for tailoring breast cancer treatment. "Many cancer doctors are already using genomic tests in their everyday practice to select patients for adjuvant chemotherapy. This reflects a growing awareness among oncologists that we are over-treating many early stage breast cancer patients with chemotherapy," Martin said.

Studies to compare and evaluate these different tests would help ensure greater numbers of European women receive the most appropriate therapy for their individual cancer, Martin said: "For many cancer doctors, especially in the USA, genomic testing has already proven its usefulness and is the standard of care for node-negative breast cancer patients in whom chemotherapy would be an option according to former traditional criteria."

"However, it appears that in Europe there is still a high degree of scepticism about the usefulness of genomic platforms, and more research comparing and validating those tests would help overcome this barrier to more personalised treatment in breast cancer."