Chapel Hill, N.C. — When it comes to prescribing medicine, doctors are learning one size does not fit all patients. A pilot trial at UNC Hospitals uses a patient's genetic profile to prescribe tamoxifen for breast cancer.

Tamoxifen is used primarily for breast cancer survivors to prevent recurrence. However, it doesn't seem to work in some patients, and doctors don't discover that until the cancer returns.

UNC researchers are looking at patients' own DNA to help them tailor the treatment. Dr. Karin True, 36, is a UNC nephrologist and a two-year breast cancer survivor.

To prevent a return of cancer, True is taking tamoxifen to block the growth factor pathway that feeds tumor cells.

“And tamoxifen not only stops the growth of breast cancer cells, it will cause them to die,” pharmacotherapist Howard McLeod, with UNC Hospitals, said.

McLeod said that in 10 percent of women, tamoxifen doesn't seem to work, but now genetic testing can identify those women.

“Many women have trouble with tamoxifen, or don't respond to it, and we'd like to get smarter about who we give it to,” Dr. Lisa Carey, director of the UNC Breast Center, said.

Carey is leading a pilot trial that uses genetic testing to identify which patients should seek other treatment options – or which women, like True, just metabolize tamoxifen differently.

“I'm an intermediate metabolizer of tamoxifen, so potentially if I'm taking the same dose as someone else who is a high metabolizer, I might not be getting enough compared to them,” True said.

After the testing, True is getting an increased dose.

As a doctor, she says she is fascinated by the idea of genetically tailored prescriptions.

“Information like this is going to help not only cancer patients, but all patients,” True said.

Women taking tamoxifen can become part of the pilot trial, which hopes to get 100 women participating. If the results are positive, it will lead to a much larger trial.

If you are interested in learning more about the tamoxifen study, please contact Donna Rowe at 919-966-4432.