A major international study has raised concerns about how some common everyday medications might affect treatment outcomes for people with breast cancer.
The research involved more than 23,000 people and was led by scientists at the University of South Australia and Flinders University.
The researchers looked at drugs that many people take for common conditions like high blood pressure, high cholesterol, heartburn, and diabetes. Their goal was to understand how these non-cancer medications might interact with cancer treatments.
One of the key findings was that proton pump inhibitors (PPIs), which are often used to treat acid reflux and heartburn, were linked to worse survival outcomes in breast cancer patients. People taking PPIs had a 36% higher chance of experiencing serious side effects from their cancer treatment.
These medications may interfere with how the immune system works or affect how the body absorbs and processes cancer drugs, but more research is needed to fully understand why this happens.
Other heart-related medications like beta-blockers, ACE inhibitors, angiotensin receptor blockers, and calcium channel blockers were also linked to a higher risk of severe treatment side effects.
However, these medications did not appear to impact overall survival rates. This means they made treatment more difficult but didn’t necessarily make breast cancer outcomes worse.
On a more reassuring note, two very common medications—statins (used to lower cholesterol) and metformin (used to treat diabetes)—did not seem to negatively affect cancer treatment or survival. This is good news for the many breast cancer patients who take these drugs for long-term health conditions.
The data used in the study came from 19 large clinical trials funded by well-known pharmaceutical companies like Pfizer, Roche, and Lilly. Researchers say it is the most detailed study of its kind so far and gives valuable insights into how cancer treatment could be improved by paying closer attention to a patient’s full list of medications.
Dr. Natansh Modi, the study’s lead author, pointed out that many breast cancer patients also deal with other health conditions and take multiple medications every day.
He stressed that this study does not mean patients should stop taking their usual drugs, but rather that doctors should regularly review all the medications a patient is using—especially while they are undergoing cancer treatment.
Senior author Associate Professor Ashley Hopkins said doctors should take extra care with patients who are taking PPIs during cancer treatment. He emphasized that no one should stop their heartburn or acid reflux medicine without talking to a doctor first, but it’s important to check whether those medications are still necessary.
Overall, the study highlights the importance of looking at the bigger picture when treating breast cancer. Cancer care should consider all aspects of a patient’s health, including the non-cancer drugs they are taking.
The researchers are now calling for more studies to explore the biological reasons behind these drug interactions. They also hope to develop better clinical guidelines so that doctors can prescribe cancer treatments more safely, even when patients are taking medications for other health issues.
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The study is published in Cancer Medicine.
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