Breast Cancer

By Christine Gorman

Breast cancer is one of those illnesses that it pays to know at least as much about as your doctor does. There's always a new study, a conflicting report or an experimental treatment to consider. Take last week's carefully worded advice about two anticancer drugs sent to the U.S. Food and Drug Administration by a panel of experts. If you don't pay close attention to the details, you could wind up doing yourself more harm than good.

In the first case, the advisory panel recommended that the FDA expand its current approval of the breast-cancer drug tamoxifen to include women who don't have the disease but are at high risk of developing it. The panel did not endorse the idea, however, that tamoxifen actually "prevents" breast cancer, saying only that it might help reduce the risk over the short term. In the second, more straightforward decision, the panel urged approval of herceptin, a gene-based treatment for some forms of advanced breast cancer.

Let's start with the more complicated case. Doctors have used tamoxifen, first of the so-called designer estrogens, to treat breast cancer for 25 years. In that time, they've learned that the drug works by starving tumors that feed on estrogen. But could tamoxifen also stop a tumor before it starts? Last spring U.S. researchers reported with great fanfare that tamoxifen can indeed decrease the risk of developing breast cancer as much as 45%.

There were, however, some significant caveats in that report. Women who took tamoxifen developed uterine cancer twice as often as those who didn't, and three women died of blood clots probably triggered by the medication. For women who are fighting for their lives, those risks may be O.K., but they're a lot to ask of someone who isn't even sick. What's more, two smaller, European studies of tamoxifen published this summer found no preventive benefits at all.

So why did the FDA panel recommend expanded approval? Its report talked about giving women more options. But let's face it: tamoxifen is already available for cancer treatment, so a lot of women are taking it "off-label" for prevention. FDA approval of a practice that is growing should make it easier for doctors to determine if their patients are sufficiently at risk to consider the drug.

That's not an easy question to answer. Indeed, it's so complicated that the National Cancer Institute has developed a computer program to help you and your doctor make sense of it. Further complicating the picture is the fact that tamoxifen's effects seem to wear out after five years. So when is the best time to take it? In your 30s? Your 40s? Your 50s?

There are two things to keep in mind as you try to sort this out. Many women think they're at high risk when they're not; just because your aunt developed breast cancer doesn't mean you'll get it. Moreover, researchers are starting a new breast-cancer-prevention trial comparing tamoxifen with raloxifene, another anti-estrogen, which in limited testing showed fewer side effects.

As for herceptin, anything that can help women in the advanced stages of breast cancer is good news. It's not a cure and does nothing for the 70% of cases that don't involve the so-called HER-2 gene. But the drug has been in desperately short supply, and FDA approval should improve that situation.

See time.com/personal for more on breast cancer. Sign up for the NCI computer program at cancertrials.nci.nih.gov