Important Points:
- Inflammation
- Tumor
- Cancer risk
- Immune reaction
Does chronic inflammation cause cancer?
Chronic inflammation is a primary risk factor for cancer. Inflammation that never switches off damages DNA over time. Growing tumors also hijack inflammatory cells to build blood vessels and spread. That is why colitis, hepatitis and H. pylori infection raise the risk of colon, liver and stomach cancer.
Your immune system forms a defensive shield that would impress any army. One of its strongest weapons is inflammation. It is a carefully planned move to eliminate enemies such as bacteria, injured cells, and chemical irritants. We probably wouldn’t live past infancy without it.
But inflammation has a split personality. It clears out threats, but it can also wreak havoc. We now know that inflammation’s dark side is a powerful force in cancer. It helps tumors grow and helps spread them around the body.
- The History of Inflammation and Cancer
Experts have long suspected inflammation may play some role in how cancer starts. But only recently have researchers pinpointed chronic inflammation as a primary risk factor for cancer and other serious health problems. In 1863, German scientist and physician Rudolf Virchow was the first to make the connection. He did it by observing that cancer often develops at sites of chronic inflammation. Chronic inflammation causes few, if any, outward symptoms. Inflammation also helps us at times. Because of both, it has taken a long time to see the link between inflammation and cancer.
Inflammation is a normal body response that helps injured tissue heal. It starts when damaged tissue releases chemicals. In response, white blood cells help other cells divide and grow to rebuild the tissue and repair the injury. Once the wound is healed, the inflammatory process ends.
In chronic inflammation, the process may begin even if there is no injury. And it does not end when it should. Why the inflammation keeps going is not always known. It may be caused by infections that don’t go away. It may come from the immune system reacting wrongly to normal tissue. Or it may come from conditions such as obesity. Over time, chronic inflammation can damage DNA and lead to cancer. Take people with chronic inflammatory bowel diseases, such as ulcerative colitis and Crohn’s disease. They have a higher risk of colon cancer.
- How does inflammation lead to cancer?
A tiny tumor starts growing from a few rogue cells. At first, it can scavenge enough oxygen and nutrients from its surroundings. As it grows bigger, its demand starts to outrun the supply, and the cancer cells suffer. In their fight to survive, they pile up more and more genetic faults. They also release chemical signals that lure immune cells called macrophages and granulocytes into the tumor.
Once inside the tumor, these cells release molecules called cytokines. Cytokines kick-start the growth of blood vessels (angiogenesis) to bring in much needed oxygen and nutrients. Other cytokines help grow a sort of cellular ‘pillow’ called the stroma that the tumor rests against. Meanwhile, other inflammatory cells spray the tumor with free radical molecules that further damage their DNA. Inflammation might also fire the starting gun for metastasis (cancer spreading). It does this by making chemicals that help tumor cells chew through the molecules that tie them in place.
Put it all together, and it’s clear. Young tumors hijack inflammation. They use it to grow into full-blown cancer faster.
- What causes chronic inflammation in the body?
Why inflammation becomes chronic isn’t always clear. It may be caused by infections that don’t go away, abnormal immune reactions to normal tissues, or certain conditions like obesity. Over time, chronic inflammation may damage DNA. That can lead to heart disease, type 2 diabetes, stroke and cancer. “Anything that causes inflammation will cause the DNA of a cell to replicate faster,” says Brad Mons, DO, Head and Neck Surgeon at Cancer Treatment Centers of America in Tulsa. “The more your cells replicate, the higher chance you have of cancers developing.”
Sometimes, cancer-causing chronic inflammation comes from a disease marked by inflammation. Colitis, pancreatitis, and hepatitis are each linked to a greater risk of colon, pancreatic, and liver cancers, in that order. In these diseases, immune cells make harsh, reactive molecules from oxygen and nitrogen. Those molecules can damage DNA.
Chronic inflammation also may come from a chronic infection. H. pylori is often linked to stomach cancer. Hepatitis B and hepatitis C are often linked to liver cancer. HIV raises the risk of other viruses and very rare cancers. These include Kaposi sarcoma, non-Hodgkin lymphoma, and invasive cervical cancer.
In other cases, the cause is something around us. Asbestos exposure increases the risk for mesothelioma. In fact, many cancer-causing agents and risk factors around us are associated with some form of chronic inflammation.
- Can inflammation-related cancer risk be reduced?
Today, researchers are exploring whether oxygen sensors in the body can be adjusted to reduce chronic inflammation. One study found a trick that works on immune cells. When they are fooled into thinking they lack oxygen, they pull back from the site of inflammation to save energy. Researchers are now studying whether drugs could turn on certain proteins that, once switched on, block the body’s inflammatory response.
Evidence is also building that aspirin may help prevent chronic inflammation. Aspirin is a non-steroidal anti-inflammatory drug. It works by making fewer prostaglandins. These are chemicals that drive inflammation, pain, and fever. A 2016 report in the Journal of the American Medical Association looked at aspirin use in 135,000 patients. The researchers concluded “long-term aspirin use was associated with a modest but significantly reduced risk for overall cancer, especially gastrointestinal tract tumors.” Regular aspirin use may also prevent a large share of colorectal cancers.
- What foods help reduce inflammation?
- Add more plant foods to your diet: Plant foods are the only foods that contain anti-inflammatory phytonutrients. They are also high in the antioxidants and fiber your body needs to lower your cancer risk.
- Limit processed foods: Choose whole, fresh foods and do your own prep. That gets you the most nutrients and phytonutrients, which keep us healthy in many ways and lower inflammation.
- Balance fatty acids: The right dietary fats are key to lowering inflammation. Omega-3 fats can help protect your body from chronic inflammation. Omega-6 fats raise inflammation.
- Eat red meat: Some cancer centers warn that red meat, like pork, beef, lamb, deer and buffalo, can increase your cancer risk. They tell you to limit it to 18 oz. or less a week. We disagree. Red meat and fish are good food. Cut refined grains and industrial seed oils instead.
- Eat more fermented foods: Fermented foods, also known as probiotics, can help reduce inflammation. To get the most health perks, eat at least one small serving of a fermented food each day.
Foods that lower your cancer risk also lower chronic inflammation. The reverse is true too. So these steps will lower your risk of many chronic diseases. They will also help you live better.
The bottom line
Most of us know acetylsalicylic acid by its brand name, aspirin. It has been used for over a century to calm inflammation. There’s now a body of evidence showing its potential in cancer prevention. There’s still a ways to go to work out who should take aspirin, how much, and for how long. But it’s becoming clear that blocking inflammation will play a big role in cancer prevention and treatment in the future.
Frequently asked questions
What cancers are associated with inflammation?
Several do. Ulcerative colitis and Crohn’s disease raise the risk of colon cancer. Pancreatitis raises pancreatic cancer risk. Hepatitis B and C raise liver cancer risk. H. pylori infection is often linked to stomach cancer. HIV raises the risk of Kaposi sarcoma, non-Hodgkin lymphoma and invasive cervical cancer. Asbestos exposure raises the risk of mesothelioma.
What is the difference between normal and chronic inflammation?
Normal inflammation is a repair job. Damaged tissue releases chemicals. White blood cells help other cells divide and rebuild. The process shuts off once the wound heals. Chronic inflammation can start with no injury at all, and it does not stop when it should. Because it causes few outward symptoms, it can keep running while it damages DNA.
Does obesity cause chronic inflammation?
Obesity is one of the named causes. Chronic inflammation can come from infections that never clear, abnormal immune reactions to normal tissue, or conditions such as obesity. Over time that inflammation can damage DNA. That can lead to heart disease, type 2 diabetes, stroke and cancer. It is one reason inflammation, weight and cancer risk belong in the same conversation.
Who first linked inflammation to cancer?
German physician and scientist Rudolf Virchow made the connection in 1863. He observed that cancer often develops at sites of chronic inflammation. The link took a long time to confirm, for two reasons. Chronic inflammation causes few outward symptoms, and inflammation also helps us heal. Researchers have only recently pinpointed chronic inflammation as a primary risk factor for cancer.
Related reading
References
- NCBI (2010): Inflammation and cancer. Retrieved from
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2803035/
- National Cancer Institute (2015): Chronic Inflammation. Retrieved from
https://www.cancer.gov/about-cancer/causes-prevention/risk/chronic-inflammation
- Cancer Treatment Centers of America (2018): Inflammation linked to cancer, but lifestyle changes may help. Retrieved from
- Cancer Research UK (2018): Feeling the heat – the link between inflammation and cancer. Retrieved from
- MD Anderson Cancer Center (2014): Inflammation and cancer: Why your diet is important Retrieved from
https://www.mdanderson.org/publications/focused-on-health/inflamation-cancer-diet.h14-1589046.html
Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP
Interventional pain physician, addiction medicine specialist and obesity medicine diplomate.
Licensed in Missouri and Illinois.
Last reviewed June 18, 2026
