This personalized test can help provide much-needed peace of mind.
If you’ve had breast cancer, you know the battle isn’t over when your initial treatment is finished.
According to Tara Sanft, MD, a breast oncologist and chief patient experience officer at Yale’s Smilow Cancer Hospital, one in eight women will develop breast cancer in their lives. Unfortunately, even after that initial diagnosis and treatment, there’s a six percent chance of a breast cancer recurrence within the first five years, which means cancer can come back or spread to other parts of the body. But cancer isn’t just a five-year battle — in fact, half of recurrences in women with hormone receptor-positive (HR+) breast cancer happen after five years. “A hallmark of hormone receptor-positive cancer,” says Dr. Sanft, “is that a recurrence can happen decades out.”
The possibility of cancer recurrence can cause a sense of uneasiness about the future. To combat the chances that cancer will come back, most women with HR+ breast cancer are put on anti-estrogen therapy (usually an aromatase inhibitor or tamoxifen) for five years after their initial cancer treatment. Since HR+ breast cancer requires estrogen to grow, this type of medication works by limiting estrogen levels in the body or blocking estrogen’s ability to attach to cancer cells. Dr. Sanft explains: “The receptors on a cell’s surface are like baseball mitts, and they catch estrogen or progesterone. In normal cell functioning, that’s fine…but with cancer, it helps the cancer grow. So we really focus on blocking that action by either removing the baseballs or putting like a grapefruit in there, so it thinks it’s holding a baseball but it’s not.” Women who do not take their anti-estrogen as prescribed may be up to 60 percent more likely to experience a recurrence.
While these drugs can be life-saving, some women experience significant side effects that impact quality of life, including bone toxicity, sexual dysfunction, and menopausal symptoms like hot flashes and joint pain.
After the first five years, a patient’s healthcare team will consider several factors in order to make a decision about whether or not it’s time to end anti-estrogen therapy. For women with early-stage, HR+ breast cancer, a test called the Breast Cancer Index test (BCI) is crucial in helping physicians and patients make this decision.
By taking a small sample of the original tumor, BCI can predict whether extending anti-estrogen therapy from 5 to 10 years will benefit a patient, as well as determine a woman’s personalized risk of recurrence. People identified by the test as likely to benefit could see a two-thirds reduction in their risk of recurrence by continuing treatment. However, for most women, continuing treatment for an additional five years is unlikely to reduce their risk of recurrence, meaning there’s no need for them to continue taking the medication.
In 2017, Dr. Sanft’s patient, Clara Ogando, was diagnosed with stage one HR+ breast cancer after a routine mammogram. She underwent chemotherapy and radiation treatment and was then put on an aromatase inhibitor for five years. Unfortunately, like many women, Ogando experienced side effects from the drugs, including “joint pain, muscle pain, and insomnia,” she says.
Five years after her initial diagnosis, Ogando received the results of her BCI test, indicating that she would benefit from extending the aromatase inhibitor treatment. “Even though I had side effects,” says Ogando, “I’d rather continue taking it if it’s going to prevent recurrence. I already did five years, so I can do another five years.” Together, Dr. Sanft and Ogando came to the decision that extended therapy was the right course of action.
“Women should understand that they have options,” explains Dr. Sanft. “There are tests like the BCI that have been validated to take some of the guesswork out. It helps us understand what benefit you are likely to have from staying on the therapy longer…that translates to more confident decisions by both doctors and patients.”
Whether your results indicate you would benefit from extended therapy or not, the Breast Cancer Index test provides invaluable information — not only can it offer peace of mind about what may happen in the future, but it can help you and your doctor make a treatment decision that’s right, and personalized, for you.
