A landmark federally funded clinical trial has provided the first real evidence that doctors can pinpoint breast cancer survivors at higher risk of relapse by detecting dormant cancer cells, and that these hidden cells can be successfully treated using already available drugs. The work, led by researchers at the Abramson Cancer Center of the University of Pennsylvania and Penn’s Perelman School of Medicine, appears in the journal Nature Medicine.

Although survival rates for breast cancer continue to improve thanks to better screening and therapies, the disease remains incurable once it comes back after initial treatment. About 30 percent of women and men experience a relapse, leaving them dependent on ongoing treatment that cannot completely remove the cancer. Some forms, such as triple negative and HER2+, often reappear within a few years, while ER+ cases can resurface even decades later. Until now, doctors had no way to identify which survivors carried dormant cells that fuel recurrence or to step in with a therapy that could prevent it.