Inflammation and Cancer: What is the Connection? 

Written by: Beth Dougherty

Inflammation is normal. It’s an essential process our bodies use to fight infections and heal wounds. But inflammation that persists can be harmful, and in some cases can increase the risk of cancer. 

Dana-Farber research into the connections between inflammation and cancer has led to new programs focused on early cancer detection and intervention. Learn more about inflammation, how to manage it, and when to seek help. 

What is inflammation? 

Inflammation is a complex process initiated by the immune system. Immune cells circulate throughout the body and respond to alarm signals, such as wounds, infections, or irritations. When alerted, these cells release molecules that call for aid, summoning more specialized immune cells into the affected area. This accumulation of cells and secretion of molecules causes inflammation. 

Inflammation appears as swelling or redness near an injury, such as a cut or sprain. It might also cause fever, aches, and pains in response to an infection.  

“When the injury or infection is resolved, the inflammatory response stops,” says Nilay Sethi, MD, PhD, a researcher and oncologist in Dana-Farber Brigham Cancer Center’s Division of Gastrointestinal Oncology. “If the process persists, it can become chronic inflammation. And that’s when things can go wrong.” 

Why does inflammation persist if it’s not supposed to? 

There are many situations that can lead to chronic inflammation. Examples include: 

  • Autoimmune disease: Autoimmune diseases are rare and involve cases where immune cells mistake healthy cells for diseased ones. A person with autoimmune hepatitis, for example, has immune cells that continually attack healthy liver cells, leading to chronic inflammation and injury to the organ. 
  • Irritants: Environmental exposures can also cause inflammation to occur and persist if the exposure continues. A smoker or a person who is exposed to asbestos might experience inflammation in the lungs caused by the continual presence of irritants in the lung tissue.  
  • Obesity and diabetes: Fat deposits, called adipose tissues, send out inflammatory signals, which can become out of balance when the body contains an excess amount of fat. Inflammatory processes can also be triggered by diabetes and dysregulation of the processing of sugar in the body. 
  • Aging: As we age, systems in the body change. Joints may develop arthritis and become inflamed. Plaque may accumulate in arteries and cause inflammation. The risk of diabetes also increases with age. A term called “inflammageing” has been coined to capture this idea, says Lachelle D. Weeks, MD, PhD, a physician-scientist in Dana-Farber Brigham Cancer Center’s Adult Leukemia Program. “As we age, we are at an increased risk of developing certain inflammatory conditions.” 

Do inflammatory conditions increase my risk of cancer? 

In individual organs, inflammation that persists over a long time in response to continued injury or illness can increase the risk of cancer. As an example, if a person develops non-alcoholic fatty liver disease, immune cells will continually work to repair the liver, putting the organ in an inflammatory state.  

The organ’s cells will respond with efforts to make repairs. But these repair efforts can put cells into a state in which they start dividing quickly. These cells might also have damaged DNA that will be passed along as cells divide. Most of the time, cellular repair mechanisms or tissue surveillance will correct or remove damaged cells without consequence. But sometimes, instead of healing the organ, abnormal cells could begin to take over and form cancer.  

Inflammation is known to increase the risk of several cancers. For example: 

  • Reflux disease can cause persistent inflammation at the junction of the stomach and esophagus, a condition called Barrett’s esophagus, which increases the risk of cancer; 
  • Inflammatory bowel diseases, such as Crohn’s disease or ulcerative colitis, can increase the risk of colorectal cancer
  • Smoking can cause persistent inflammation and damage in the lungs that can increase the risk of lung cancer. 

While inflammation increases the risk of cancer, it does not always lead to cancer.  

“The increased risk of cancer varies from person to person and can depend on many other factors, including whether a person has a genetic risk for cancer,” says Sethi, whose research has helped identify some of the ways that inflammation affects the gastrointestinal system and can increase cancer risk.  

Are inflammatory conditions related to blood cancer? 

Inflammation can influence the development of blood cancer. Inflammation caused by arthritis, heart disease, or other conditions can result in elevated levels of inflammatory molecules throughout the body. This is called systemic inflammation. 

Weeks’ research has shown that systemic inflammation and aging can contribute to a condition called CHIP (clonal hematopoiesis of indeterminate potential). CHIP occurs when blood cells acquire mutations and then divide and spread and become more and more common in a person’s bloodstream.  

CHIP can be a precursor to cancer, but the link to cancer depends on the types of mutations in the cells. In some cases, the mutations increase the risk of cancer. In other cases, they don’t.  

“It is important to understand that blood cancers are extremely rare,” says Weeks. “We only start to consider blood cancer as a possibility if a patient has low blood counts or evidence that their bone marrow is not functioning well.”  

What can I do to reduce inflammation and lower my risk of cancer? 

A healthy lifestyle will go a long way to reducing inflammation. This includes eating fresh, whole foods whenever possible, exercising, and getting good sleep. If you smoke, consider quitting. (Get help here.) If you drink alcohol, consider stopping or limiting your intake. In addition, try to eat fewer ultra-processed foods if possible. 

Following the recommended cancer screening guidelines is also important because screening helps identify cancer early, when it is more treatable. 

In addition, Sethi and Weeks both recommend that you listen to your body and see your doctor if something doesn’t feel right.  

“Inflammation that warrants seeing a doctor usually isn’t subtle,” says Weeks. “If you experience unexplained and persistent joint pain, abdominal pain, fevers, or swelling, see your primary care doctor.” 

How can Dana-Farber help? 

Experts at Dana-Farber are committed to finding cancer early, and recently launched the Dana-Farber Centers for Early Detection and Interception. The Centers focus on earlier intervention for those with a high risk of developing future cancers, including both blood cancers and solid tumors.  

The Centers aim to: 

  • Transform cancer care from reactive to proactive through early detection, including evaluations of precursor conditions that might be related to inflammation, such as CHIP for blood cancers or Barrett’s esophagus. 
  • Improve screening access, particularly in communities in which screening rates are lower, to diagnose cancer at an earlier stage. 
  • Identify treatment options for patients at risk, including offering clinical trials that aim to intercept precursor conditions and stop cancer before it starts or progresses further.