(December 5, 2012)—Breast cancer patients who take the drug tamoxifen can cut their chances of a recurrence of the cancer and death from a return of the disease if they stay on the pills for 10 years instead of five years as doctors recommend now, a new study finds.

The results, which could change treatment, especially for younger women, are a surprise because earlier research suggested that taking the hormone-blocking drug for longer than five years might be harmful.

In the new study, women who took tamoxifen for 10 years lowered their risk of a recurrence by 25 percent and of dying of breast cancer by 29 percent compared to those who took the pills for just five years.

The study was discussed at a cancer conference in Texas and published in the journal Lancet.