How weight loss pills can help some cancer patients live longer

Weight-loss injections popularized to help people shed pounds may help some patients with advanced cancer live longer when the disease has spread to the brain, according to a new study.

This drug belongs to a group of drugs called GLP-1 receptor agonists, and includes Vigovi and Ozympic. They were first developed to treat type 2 diabetes, but in the last few years they have gained worldwide attention as many people who take them experience significant weight loss.

The new research does not show that these injections directly treat cancer. Instead, it suggests something more subtle but potentially important: They might help some patients live longer.

Research focuses on brain metastases. This happens when cancer cells travel from somewhere else in the body – such as the lungs, breast or skin – to form tumors in the brain. Unfortunately, brain metastases are relatively common and usually indicate that the cancer has reached a late and dangerous stage.

Many patients with this condition also have type 2 diabetes. This is important because the condition can lead to serious illness. High blood sugar can cause chronic inflammation, damage blood vessels and weaken the body’s ability to cope.

In my own clinical practice, I often prescribe steroids to patients with brain metastases to help manage symptoms such as swelling in the brain. Steroids can be very effective, but they also raise blood sugar levels and can make diabetes harder to control. This has led researchers to question whether GLP-1 drugs may have additional benefits.

When diabetes medication meets cancer treatment

Laboratory studies suggest that they may protect brain cells, reduce inflammation and help maintain the brain’s blood supply. However, until now, there is very little evidence from daily clinical practice showing how patients with diabetes and brain metastases fare when they take these drugs.

The new study, published in Jam network openedset out to explore this question. The researchers used a medical database of anonymized health records from 151 hospitals and health care systems worldwide.

They looked for adults with three conditions: cancer, type 2 diabetes and brain metastases. The records cover patients seen between 2018 and 2024. The researchers were particularly interested in whether these patients were given GLP-1 drugs – such as semaglutide, dolglutide, liraglutide or terzepatide – around the time their diabetes and brain metastases were first diagnosed.

For a fair comparison, the team matched people who had received one of these injections with the same patients who had not. They took into account factors such as age, sex, type of cancer, other medical conditions and treatments including chemotherapy, radiotherapy and steroid use. Statistical adjustment cannot eliminate all differences between groups, but it helps to reduce the risk that the results are simply healthy at the start of a group.

In total, the researchers identified more than 19,000 patients with cancer, brain metastases and type 2 diabetes. Among them, 866 were treated with GLP-1 drugs, while more than 11,000 were not. After careful adjustment, the analysis compared two matched groups of 850 patients who were each similar in their cancer, body mass index, diabetes control and other health issues.

The researchers then followed these patients up to three years after their brain metastases were first recorded. Their main question was straightforward but important: How many people of each group died during this period?

The researchers found that patients who took the GLP-1 drug were significantly less likely to die during the follow-up period than those who did not. Overall, people taking GLP-1 drugs were nearly 37% less likely to die within three years.

This pattern was consistent across several major types of cancer, including lung cancer, breast cancer and melanoma. It is also expressed in various drugs in the GLP-1 class.

When researchers compared GLP-1 drugs with other modern diabetes treatments — including drugs including SGLT2 inhibitors and DPP-4 inhibitors — the GLP-1 group still looked better. This suggests that something about GLP-1 signaling may be beneficial on its own, rather than just coming from better blood sugar control.

Important limitation

Even so, the researchers emphasize an important limitation. This study looked at medical records rather than testing treatments in a controlled trial. To do this, researchers will need randomized clinical trials in which patients are randomly assigned to receive a GLP-1 drug or another drug and then followed over time.

So how can these so-called weight loss pills help people whose cancer has spread to the brain?

About the author

One possibility is that they indirectly help improve diabetes. Better blood sugar control, weight loss and improved heart health can help patients cope better with surgery, radiotherapy or chemotherapy.

But it may also have more direct effects on the brain. Scientists have discovered that GLP-1 receptors are located in brain tissue and play a role in controlling inflammation, protecting nerve cells and helping maintain the blood-brain barrier – a protective layer that keeps harmful substances out of the brain.

Animal studies suggest that activating these receptors can reduce damage to brain cells and help them function properly. In theory, this might help the brain better tolerate metastatic tumors or make it a less favorable environment for cancer cells to grow. New clinical findings are consistent with these ideas, although they still do not tell us which mechanisms are most important in people.

For patients and families reading about this research, it’s important to understand what the results do—and don’t—mean. The study does not suggest that people with brain metastases should rush to start GLP-1 drugs, nor that these drugs can replace standard cancer treatments such as radiotherapy, surgery, targeted therapies or immunotherapy.

Potential benefits have been seen especially in people who already had type 2 diabetes. Like any drug, these injections can cause side effects such as nausea and vomiting, and there is ongoing discussion about rare but serious risks.

Anyone considering them needs careful guidance from their oncology and diabetes teams rather than making decisions based on one study.

Still, the findings open up an exciting new line of research linking cancer, metabolism and brain health. If future trials confirm that GLP-1 drugs do indeed improve survival in patients with brain metastases and diabetes, they could eventually become part of supportive care for people with this difficult complication.