This may be the most effective therapy for aggressive hereditary breast cancer.

A new treatment significantly improves survival rates for patients with aggressive, hereditary breast cancers. In a trial treating these tumors with chemotherapy followed by a targeted cancer drug before surgery, 100% of patients survived the critical three-year period after surgery .

The discovery, published in Nature Communications , could become the most effective treatment to date for patients with early-stage breast cancer with inherited mutations in the BRCA1 and BRCA2 genes.

Breast cancers with defective copies of the BRCA1 and BRCA2 genes are difficult to treat, and became more widely known when actress Angelina Jolie , a carrier of the BRCA1 gene, underwent a preventive double mastectomy in 2013.

The current standard treatment consists of shrinking the tumor with chemotherapy and immunotherapy before surgical removal. The first three years after surgery are a critical period, with the highest risk of relapse or death.

The Partner trial, developed by researchers at the University of Cambridge and Addenbrooke's Hospital (UK), took a different approach and demonstrates two innovations: the addition of olaparib and chemotherapy before surgery, and the benefits of carefully timing when treatments are given to patients.

The trial recruited patients from 23 National Health System centers across the United Kingdom.

The authors believe their findings could be applied to other cancers caused by defective copies of the BRCA genes, such as some ovarian, prostate, and pancreatic cancers.

“ It’s rare for a study like this, and for such aggressive cancers, to achieve a 100% survival rate . We’re incredibly excited about the potential of this new approach, as it’s crucial that we find a way to treat and hopefully cure patients diagnosed with BRCA1- and BRCA2-related cancers,” said Jean Abraham, the trial’s lead author.

For AstraZeneca ’s Mark O’Connor, the Partner trial highlights “the importance of detecting and treating cancer early, as well as the value of innovative science in informing clinical trial design, in this case using bone marrow stem cells to identify timing gaps for combinations. While the results need to be validated in a larger study, they are incredibly exciting and have the potential to transform outcomes for patient populations with unmet clinical need.”

"One of the best ways to beat cancer sooner is to use the treatments we already have more effectively," says Michelle Mitchell of Cancer Research UK .