Many women who face high risk of developing breast cancer may hesitate or refuse to take preventative drugs, according to a study headed by Harvard researchers.

The team surveyed 129 high-risk women about the drug Tamoxifen, the first and only drug approved by the FDA to inhibit breast cancer.

Of the women surveyed, 37 said that they would take the drug, 35 said that they would take it in another clinical trial, 31 women said no, and 26 were undecided.

Four months after the original survey, 15 people who were originally undecided declined.

According to Sharon L. Bober, a clinical psychologist in the department of psychiatry at the Beth Israel Deaconess Medical Center and Dana Farber Cancer Institute who headed the study, the results were worrisome not only because women were denying preventive treatment, but that there were still women who were unsure about treatment.

“‘I don’t know’ is a ‘no’ by default,” said Bober, who is also a clinical instructor at HMS. “It’s one thing saying no, I don’t want to deal with the side-effects and so I’m going to get more exams, but it’s bad to be in a limbo state and not do anything at all. It’s important to follow up on these women to see what they are doing.”

But the implications go much further, Bober said, since the choice these women face soon “will be faced by all of us.”

“If you look at all of the advances in cancer genetics, there will be a growing implication for chemoprevention—chemical agents that will potentially mitigate or prevent diseases,” Bober said. “Most medications will always have some sort of side effect.”

Bober said she was also concerned that women could be basing these decisions from an uninformed standpoint.

“We don’t live in a society where people are mathematically competent,” Bober said. “Women can easily misperceive side-effects.”

Known complications of tamoxifen are: hot flashes, increased risk for cataracts, uterine cancer, blood clots, sexual function and vaginal dryness.

But Bober said these risks are far outweighed by the decrease in risk for breast cancer.

“Hot flashes are uncomfortable, but not life-threatening; uterine cancer is serious, but the chances of that happening is very, very small,” Bober said. “The fact is, your risk of breast cancer is significantly higher than that of you getting uterine cancer.”

Since patient psychology plays a key role in patients’ decisions about treatment, Bober believes that doctors hold part of the responsibility as well.

“If you’re asking a patient to make a decision that’s complicated with risks and benefits, then their fears and anxieties are on the table,” she said. “Maybe physicians will have to partner with health psychologists and other health educators in how to counsel patients.”

Tamoxifen has been used to treat cases of advanced breast cancer for over two decades, but has only been used as a preventative measure in the last 10 years.

Tamoxifen is a selective estrogen receptor modifier, a type of drug that prevents estrogen—a key player in breast cancer— from binding to cells in breast tissue.

—Staff writer Risheng Xu can be reached at xu4@fas.harvard.edu.