GLP-1/GIP drugs like Zepbound have transformed weight-loss treatment. They may also be able to help reduce the risk of breast cancer recurrence for some people.
Dallas breast cancer specialist Dr. Joyce O’Shaughnessy, a nationally recognized oncologist and researcher with Baylor University Medical Center and Texas Oncology, is leading the research involving women with higher-risk, hormone receptor-positive breast cancer that has spread to the lymph nodes.
The Baylor TRIM trial is following women with a BMI of 27 or higher and testing their blood every three months for circulating tumor DNA, a potential sign that microscopic cancer remains in the body. If it is detected, participants receive tirzepatide, the GLP-1/GIP medication sold as Zepbound, with the goal of significant weight loss. Researchers then monitor whether the tumor DNA declines or disappears and whether the cancer returns.
Why weight matters
O’Shaughnessy said obesity and significant weight gain after a breast cancer diagnosis can increase the risk of recurrence. Excess weight can contribute to hormones and inflammation that may “wake up dormant cancer cells.”
The connection is particularly important after menopause. Postmenopausal weight gain, she said, is a risk factor both for developing breast cancer and for recurrence among women who have already had it.
What the GLP-1 study has found so far
It is still too early to know whether tirzepatide can actually prevent cancer from returning.
What researchers do know is that it is successfully helping women in the trial lose weight. The next question is whether that weight loss is accompanied by a reduction or disappearance of circulating tumor DNA and, ultimately, fewer recurrences.
What women can do now
While the GLP-1 research continues, O’Shaughnessy pointed to several steps women can take now to reduce risk.
- Annual mammograms beginning at age 40 and knowing the cancer history on both sides of the family, with genetic testing when appropriate.
- Maintaining a healthy weight after menopause and getting regular exercise can also reduce risk. O’Shaughnessy said even two to three hours of moderate-paced walking can make a difference.
- Avoid alcohol. “Even one drink a day increases risk modestly,” Dr. O’Shaughnessy said, while two drinks a day increases it moderately.
For O’Shaughnessy, the emerging GLP-1 research adds a potentially important new question to breast cancer prevention: Can weight control after treatment do more than improve overall health and actually help keep cancer from coming back?
“I'm even more excited about the prospects now than we were when we first launched the trial,” O’Shaughnessy said.
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