DNA testing helps identify breast cancer treatment

The first large-scale study of whole-genome testing identified those breast cancer patients who might benefit the most from certain treatments, according to new research published online in Lancet Oncology.

The researchers from several institutions in France tested all the DNA of tumor cells from more than 400 women with advanced breast cancer. The goal was to see whether whole-genome analysis could identify unique characteristics and abnormal genes in the metastatic tissue, which could then be targeted for treatment in later trials.

Dr. Fabrice André, from Institut Gustave Roussy, and colleagues looked at the quality of tumor samples, the proportion of women for whom the genomic analyses could be done, and the proportion for whom a targeted therapy could be offered. They took biopsy samples from 407 patients from 18 centers across France (Lancet Oncology, February 7, 2014).

The group was able to perform whole-genome analysis in two-thirds of the patients. Forty-six percent of the 423 enrolled patients were found to have a targetable genomic alteration, while 39% had a rare alteration.

To date, 28% of the women with targetable alterations have been matched with new treatments that are being tested in clinical trials, André said in a statement released by the journal. The team's goal is to have 30% of the enrolled patients in clinical trials testing therapies targeting the alterations identified in their tumors.

"Our findings indicate that large molecular screening programs, performed in the context of clinical trials, are helpful to see whether a patient with metastatic cancer could be eligible for a targeted therapy matched to a genomic alteration," André said.