Obesity and Gynecological Cancer

We know that obesity is a significant risk factor for and contributor to increased sickness and death from heart disease, diabetes, osteoarthritis, liver and kidney disease, sleep apnea, and depression. Obesity also relates to a greater likelihood of developing some cancers, including some gynecologic cancers. It can also make some cancers harder to diagnose and treat.

Obesity can contribute to gynecologic cancer.
Obesity causes changes in hormones and metabolic pathways. It also increases inflammation. These changes create an environment where cancer can thrive. Increased estrogen signaling, obesity‐related insulin resistance, and chronic low‐grade inflammation all stimulate cell-building processes, inhibit natural cell death, and stimulate cell proliferation. All of these factors contribute to cancer, which is characterized as cells growing out of control.

For example, obesity profoundly increases the risk of developing endometrial adenocarcinoma, particularly the type 1 or endometrioid variant. These tumors are estrogen respondent and usually develop within a thickened endometrial lining. Type 2 tumors are less responsive to estrogens and develop within tissues that have started to degenerate. Obesity increases the risk of type 1 tumors by roughly three‐fold and almost two‐fold for type 2 tumors.

Lowered immune function among people with obesity can relate to persistent cervical infection by the high‐risk HPV strains that can cause cervical cancer. This may be a result of increased microbial diversity, which can lead to HPV cells changing to cancer cells on the cervix.  

Obesity can make gynecologic cancer harder to find.
For many reasons, increased body weight is recognized as an independent predictor of gynecologic cancer screening. A number of large, retrospective studies have found significantly lower Pap test and mammography rates among women with obesity. Fewer screenings in this group relates to more advanced cancers. In addition, obesity may make some symptoms harder to spot. For instance, abdominal bloating or swelling is among the most common early symptoms of ovarian cancer. Extra weight in the abdominal area can make it difficult to see cancer-related swelling, which can relate to a delayed diagnosis. 

Obesity can make gynecologic cancer harder to treat.
Obesity can also play a hand in increased surgical complication with higher infection rates and an increased need to switch from a less invasive procedure to a more invasive one. Obesity may also have increased radiation complications, and there is no current consensus regarding appropriate chemotherapy dosing with increased body mass index.

Knowing that one’s body processes and size may affect one’s cancer risk, diagnosis, and treatment could be helpful as women learn about and seek cancer screening. In addition, doctors are working hard to limit bias that may have previously associated obesity with disinterest in health or an unwillingness to get screened. Together, we can equalize access to screening opportunities for all women and catch more cancers earlier, when they are easier to treat.

Kimberley Sampson, MD, is the chair of the Department of OB/GYN at Southwestern Vermont Medical Center, part of Southwestern Vermont Health Care, in Bennington.