The Role of Chronic Inflammation in Cancer

While inflammation is the body’s defense mechanism against pathogens, damaged cells, and chemical irritants, it also has a dark side. Marilyn Hammer, PhD, DC, RN, of New York University College of Nursing, and Raymond DuBois, MD, PhD, of Medical University of South Carolina, explain how chronic inflammation increases the risk for cancer, contributes to adverse events during cancer therapies, and impacts treatment outcomes at the Oncology Nursing Society (ONS) 41st Annual Congress held April 28 to May 1 in San Antonio, Texas.

In their session, American Association for Cancer Research/ONS Bench to Bedside: The Role of Inflammation in Cancer (and the Tumor Microenvironment), they discuss acute vs chronic inflammation, viruses and cancer, current research, and how nurses can help educate patients on ways to minimize inflammation.

An acute inflammatory response to a microorganism or trauma would be considered normal and is generally short-lived (days to weeks), whereas chronic, persistent inflammation is generally triggered by additional factors over time (months to years). Infectious agents, smoking, exposure to chemicals (asbestos), stress, and even a poor diet can lead to chronic inflammation.

When there is structural damage to immune cells due to chronic inflammation, there is an inability to detect and eliminate foreign substances, which in turn interferes with mechanisms that normally detect and arrest aberrant cell growth. For example, someone infected with the hepatitis B or C virus may be at risk for developing liver cancer, or someone who has contracted the human papillomavirus (HPV) would be at risk for cervical, penile, and/or oropharyngeal cancers-all due to chronic inflammation.

Tumors can start to develop from this process and triggers a perpetual inflammatory cycle within the tumor microenvironment. As these defective cells accumulate more genetic abnormalities, cytokines (or chemokines, prostaglandins) are secreted from tumor cells to recruit leukocytes; this in turn can jump-start angiogenesis. Blood vessel growth will help to “feed” cancer cells by providing a rich supply of oxygen and nutrients.

To treat or prevent these inflammatory cancers before they develop immunotherapy treatment options are gaining ground and are having an impact on various types of cancers associated with inflammation. Immune checkpoint inhibitors, Gardasil, and monoclonal antibodies (trastuzumab) are just a few examples. These kinds of therapies help the immune system to recognize and arrest cancer cell formation.

The good news is that there are studies taking place that focus on stopping chronic inflammation before it starts: “We should focus on inflammatory changes early on in cancer development as part of the Moonshot initiative,” said Dr. DuBois. In addition to precision medicine, studies on cancers specifically linked to chronic inflammation along with glycemic studies are also being done.

Oncology nurses are in a great position to help educate their patients on ways to help prevent inflammatory cancers. Promoting anti-inflammatory nutrients, such as fish, fruits and vegetables, lean proteins, and whole grains, is a start. Many of our foods have been genetically modified and no longer contain the necessary components of a naturally nutrient-dense food. In addition to diet, encouraging physical exercise, offering help with smoking cessation, and minimizing stress are other ways in which patients can decrease or prevent inflammation.