Ovarian cancer sometimes develops in addition to other health conditions. These health issues may increase the risk of ovarian cancer, make it harder to treat, or affect outlook. When a condition develops during another disorder or after a treatment, doctors call it a comorbidity or a complication.

Ovarian cancer may be more likely to occur in people with diabetes, and diabetes may affect ovarian cancer prognosis (outlook). Diabetes mellitus is a disorder that affects how the body uses sugar. People with diabetes don’t have enough insulin. This hormone, made by the pancreas, helps the body’s cells use sugar for fuel. When the body can’t make or use insulin, cells don’t absorb as much sugar, and blood glucose (blood sugar) levels rise. Too much sugar in the blood is called hyperglycemia.

There are a few main types of diabetes:

• Type 1 diabetes — The pancreas is not able to make any insulin.
• Type 2 diabetes — The body may not make enough insulin, and cells aren’t able to use insulin as well as they should.
• Gestational diabetes — This may develop in people who are pregnant.

Causes and Risk Factors

People with diabetes are more likely to be diagnosed with multiple types of cancer, including breast cancer, colorectal cancer, and endometrial cancer (cancer of the uterus). In one recent study, researchers looked at whether diabetes raised ovarian cancer risk. They found that women with diabetes were 20 percent more likely to develop ovarian cancer than women without.

The risk of developing ovarian cancer is highest in those with type 1 diabetes, although people with type 2 diabetes also have an increased risk. People with gestational diabetes may not have a higher risk of ovarian cancer, although more research needs to be done in this area. There is a stronger link between diabetes and ovarian cancer in Asian women than there is in women of other races or ethnicities, according to a 2017 study.

Experts aren’t yet sure how diabetes and ovarian cancer are linked. The two conditions may share some risk factors. Alternatively, diabetes can create changes in the body that make it easier for cancer cells to grow. Certain diabetes treatments may also raise cancer risk.

Shared Risk Factors

Some of the same factors can increase the risk of both conditions. For example, ovarian cancer and type 2 diabetes are more likely to develop as a person gets older. Although people can’t do anything about this particular risk factor, there are other factors under a person’s control.

Smoking can increase the risk of a particular subtype of ovarian cancer called a mucinous tumor. Likewise, smoking makes a person 30 percent to 40 percent more likely to develop type 2 diabetes. Quitting smoking — or never starting — can decrease your risk of these and other diseases.

People who are more physically active are less likely to develop ovarian cancer and diabetes. Experts often recommend getting at least 150 minutes of physical activity per week. This can be divided up however you want. For example, you could exercise for 50 minutes three days per week, or go on a half-hour walk five days per week.

Obesity can also lead to a higher risk of both conditions. Doctors often use a measurement called body mass index (BMI) to determine whether a person’s weight puts them at risk for developing other health conditions. Maintaining a healthy BMI may help prevent ovarian cancer and diabetes.

Diabetes May Directly Raise Cancer Risk

Researchers are still studying how diabetes can change the body and make it easier for cancer to grow. Some researchers have proposed a few possibilities:

• Ovulation (the process where the ovary releases an egg) leads to a small amount of damage to the ovary. High blood glucose levels can make it harder for the body to heal damage, leading to a greater chance of ovarian cancer.
• Increased blood glucose levels can lead to inflammation, which causes the body to produce molecules that encourage cancer cells to form or grow.
• Too much sugar in the blood can damage a cell's DNA, occasionally leading to cancer-causing gene mutations.
• Hyperinsulinemia (increased insulin levels) can make cancer cells grow and divide.
• High levels of insulin can increase the amount of estrogen in the body, which can increase ovarian cancer risk.

Diabetes Treatments and Cancer Risk

Some diabetes therapies may affect cancer risk. People with diabetes often need to take insulin. It’s possible that insulin feeds tumors and makes them grow. Additionally, some research has found that diabetes medications like sulfonylureas may lead to higher cancer risk. However, other treatments such as Glucophage (metformin) might reduce the chances that a tumor will develop.

More research is needed before doctors fully understand how different diabetes treatments affect cancer risk. So far, the evidence is not quite clear. Experts say that most people don’t need to consider cancer risk when choosing a diabetes treatment plan. However, this may be more important for people who have a high risk of developing ovarian cancer, such as those with a family history. If you are at high risk, talk to your doctor about whether diabetes treatment options affect cancer risk or prognosis.

Diabetes and Ovarian Cancer Prognosis

People with diabetes usually have a worse prognosis when they are diagnosed with ovarian cancer, compared to those without the condition. They are more likely to relapse (have their cancer come back after being treated). Diabetes also leads to lower overall survival rates:

• People with diabetes live an average of 2.2 years after developing ovarian cancer.
• People without diabetes survive for 3.5 years on average after an ovarian cancer diagnosis.

Many other factors also play a role in ovarian cancer outlook. For example, people with diabetes who develop ovarian cancer are more likely to be overweight or obese and have other health conditions such as heart disease or high blood pressure. These prognostic factors can increase a person’s chances of having a poor outcome by increasing complication rates during surgical procedures to remove cancers and making it harder to deal with the stresses and side effects of chemotherapy. Working with your health care team to control all of your health conditions may help improve your quality of life and keep you feeling as good as possible.

It’s not yet clear whether diabetes treatments affect ovarian cancer outlook. Some studies have found that taking metformin may lead to better survival rates for ovarian cancer. Others have found that diabetes medications can lead to a worse outlook. Some people have found that taking metformin doesn’t change their prognosis. More research needs to be done to determine whether diabetes treatments affect ovarian cancer outlook.

Managing Diabetes

People with diabetes often use lifestyle changes and medications to manage their condition. The treatments you receive may vary based on what type of diabetes you have, whether you have other health conditions, how well the treatments control your blood sugar, the cost of the therapy, and your personal preferences.

Sometimes, there may be an overlap between diabetes symptoms and ovarian cancer treatment side effects. For example, chemotherapy and diabetes can both cause peripheral neuropathy — nerve damage that leads to pain, tingling, or weakness in the hands and feet. Having pre-existing diabetic neuropathy may increase the likelihood of developing coexisting chemotherapy-induced neuropathy. One MyOvarianCancerTeam member who has diabetes shared their experience with this problem. “The most inconvenient thing is the neuropathy in my feet,” they said. “Between the chemo and diabetes, my feet are so sensitive.”

Making sure your diabetes is under control may help improve your quality of life as you undergo ovarian cancer treatments. Try to keep up with all of your follow-up appointments and tests for both your ovarian cancer and diabetes and tell your doctor about any new health issues.

Lifestyle Changes for Diabetes

Diabetics often need to change the way they eat. Eating small, regular meals helps keep blood sugar levels from spiking too high. People with diabetes also need to eat fewer refined carbohydrates and more foods that contain fiber. Tracking blood sugar levels throughout the day is also important.

Some MyOvarianCancerTeam members have reported that their doctor or nutritionist recommended certain tips for a healthy diet. However, diabetics may have different dietary requirements that need to be considered. One member with diabetes wrote, “I’m actually on a plant-based diet. I do eat a lot of veggies and some fruit, although I can’t eat a lot of fruit because I am a type 1 diabetic.”

If you have diabetes, make sure your health care team is aware and can give appropriate advice for your condition.

Getting physical activity throughout the day also helps people manage blood sugar levels. Eating healthy and exercising to lose weight may improve signs of diabetes.

Insulin and Diabetes Medications

People with type 1 diabetes and some with type 2 diabetes take insulin to help lower their blood sugar levels. Insulin may be injected with a needle and syringe or an insulin pen or breathed in with an inhaler. Some people use a pump that delivers small doses of insulin during the day.

Many other medications can also help treat diabetes. These drugs may be a pill, a liquid that is swallowed, or a liquid that is injected under the skin. Diabetes medications work in different ways to treat diabetes. They may:

• Allow the body to better use insulin
• Increase the amount of insulin that the body makes
• Prevent the liver from making sugar
• Help the body get rid of extra sugar through the urine

Surgery for Diabetes

For some people, lifestyle changes, insulin, and medications don’t manage diabetes well enough. Surgery is a more aggressive option. Some people with type 2 diabetes undergo weight loss surgery, which can help get blood sugar levels under control. People with type 1 diabetes may be able to undergo surgery in which pancreas cells or the entire pancreas is transplanted from a donor. Clinical trials may also be a way to access additional treatment options.

Talk With Others Who Understand

MyOvarianCancerTeam is the social network for people with ovarian cancer. More than 3,000 members come together to ask questions, give advice, and share their stories with others who understand life with ovarian cancer.

Are you living with ovarian cancer or diabetes? Share your experiences in the comments below, or start a conversation by posting on MyOvarianCancerTeam.