Study: Some drug combos may raise breast cancer risk

? Breast cancer survivors risk having their disease come back if they use certain antidepressants while also taking the cancer prevention drug tamoxifen, worrisome new research shows.

About 500,000 women in the United States take tamoxifen, which cuts in half the chances of a breast cancer recurrence. Many of them also take antidepressants for hot flashes, because hormone pills aren’t considered safe after breast cancer.

Doctors have long known that some antidepressants and other medicines can lower the amount of tamoxifen’s active form in the bloodstream. But whether this affects cancer risk is unknown.

The new study, reported Saturday at a cancer conference in Florida, is the largest to look at the issue. It found that using these interfering drugs — including Prozac, Paxil or Zoloft — can virtually wipe out the benefit tamoxifen provides.

Many doctors question the magnitude of harm from combining these medicines, and a second, smaller study suggests it may not be very large.

But the bottom line is the same: Not all antidepressants pose this problem, and women should talk to their doctors about which ones are best.