Obesity and Cancer Care

This month's newsletter is written by guest author Amelia Corl. Amelia is a graduate student at The George Washington University’s Milken Institute School of Public Health and a Research Assistant with the STOP Obesity Alliance. This article was written as a component of the author’s Applied Practice Experience project titled “The Intersection of Cancer Care and Obesity Care.”

The COVID-19 pandemic and the risk it poses to those with obesity has brought public attention to the way obesity interacts with other life-threatening diseases. Although it is well-known that obesity is linked to type 2 diabetes and heart disease, only 53% of Americans are aware that obesity is associated with cancer. Furthermore, the evidence supporting a causal association between obesity and cancer continues to grow. The International Agency for Research on Cancer has determined that there is now sufficient evidence to link excess body fat to 13 different cancers.

Although obesity is associated with cancer incidence with 5 to 10% of new cases of cancer attributable to obesity each year, obesity can affect a patient in any stage of cancer care, including during or after cancer treatment. Additionally, cancer and cancer care can have a profound effect on a patient’s weight. Understanding the relationship between obesity and cancer, as well as the interaction between obesity treatment and cancer care, becomes more urgent every year as obesity rates rise.

Obesity poses difficulties for patients during cancer treatment and may lead to increased side effects or decreased effectiveness of the treatment. As demonstrated in the graphic below, taken from the STOP Obesity Alliance’s new Obesity and Cancer fact sheet, specific types of cancer treatment may affect those with obesity differently.

Not only can weight affect cancer treatment, but cancer treatment can also affect weight. It’s not uncommon for cancer patients to experience significant weight gain or loss during treatment. Side effects of treatment can also affect a patient’s weight management; eating nutritiously can be difficult when patients experience nausea or vomiting and cause barriers to exercise due to treatment-related pain and fatigue. In addition, late effects of cancer treatment may continue to affect weight management in cancer survivors long after treatment concludes.

When it comes to patients with obesity in cancer care, the American Society for Clinical Oncology recommends that oncologists take an active role in addressing weight with their patients and urges cancer care providers to be aware of the intersection of obesity and cancer. Registered dieticians who help patients maintain nutritious diets throughout treatment can also be an essential part of a cancer care team. Cancer survivors are advised to continue weight management and healthy habits after treatment to maximize their health.

For those with overweight or obesity, weight loss can be an important cancer prevention tool. Although the mechanisms that link obesity and cancer vary, one potential connection is higher levels of certain hormones like estrogen. Bariatric surgery can decrease the odds of hormone-related cancers like breast and prostate cancers. While more research is needed to fully understand the effect of weight loss on cancer risk, it is clear that safe and effective obesity treatments should be made accessible to those who need them.