Study Suggests Genomic Health Test Could Cut Down Use of Chemotherapy for Breast Cancer Patients

California-based molecular laboratory Genomic Health has released a new European study suggesting that precision medicine for breast cancer patients could significantly improve long-term survival rates for those diagnosed with more virulent strains of the disease.

The study, which was conducted in Germany and recently published in the Journal of Clinical Oncology, focused on the use of Genomic Health's OncoType DX assay, which analyzes tumors and suggests a treatment pathway based on their genetic structure. The study was conducted at more than 90 cancer treatment clinics in Germany and involved nearly 3,200 patients diagnosed with estrogen-receptor positive, HER2-negative, early-stage breast cancer. The median age of the study group was 56. About 41 percent had the cancer spread into their lymph nodes; about one-third had stage three breast cancer.

About 15 percent of the patients in the study with a low score for risk of recurrence of the disease underwent hormone therapy alone, a diversion from the standard of care for most breast cancer patients. The three-year survival rate for that cohort was 98 percent. That was unchanged compared to the cohort of patients with a moderate risk of recurrence who underwent both hormone therapy and chemotherapy. Those patients with a higher risk of recurrence had only a slightly lower three-year survival rate of 92 percent.

"A low recurrence score result identifies patients who can be safely spared chemotherapy without compromising outcomes," said Nadia Harbeck, MD, PhD, head of the breast cancer unit at the University of Munich and one of the study's co-authors.

Over five years, the survival rates without a recurrence of cancer in both the low and moderate risk groups was 94 percent; it was 84 percent among those with a high risk for recurrence.

"The compelling suite of new global prospective outcomes data generated in the last six months proves that tens of thousands of patients worldwide can forgo chemotherapy and its harmful side effects based on a low recurrence score," said Steven Shak, M.D., Genomic Health's chief scientific officer.

Takeaway: Genomic Health's European breast cancer study strongly suggests that many patients being treated for the disease do not need to undergo chemotherapy.