Studies have shown that the incidence of cancer in diabetic patients is higher than in non-diabetic patients. Diabetes mellitus, in particular, increases the risk of breast, colon, pancreatic, liver and uterine cancers.
The main reasons for the high incidence of cancer in diabetic patients are the presence of common risk factors such as age, gender, obesity, smoking, diet, physical inactivity and alcohol consumption in both disease groups. Hyperglycemia (high sugar), insulin-like growth factors and insulin resistance-hyperinsulinemia are the most important biological mechanisms that show the relationship between cancer and diabetes.
Yeni Yüzyıl University Gaziosmnapaşa Hospital, Department of Medical Oncology, Assoc. Dr. Yakup Bozkaya answered what should be known about the relationship between diabetes and cancer.
Diabetes increases the risk of which cancers the most?
Diabetic patients are at increased risk for many cancers. These include cancers of the liver, pancreas, bile ducts, gallbladder, uterus, colon and rectum, breast, kidney, bladder and lymph (non-Hodgkin lymphoma). On the contrary, the risk of prostate cancer decreases in diabetic patients. This is likely because diabetic people have low testosterone levels.
What should you pay attention to?
It is necessary to eliminate the risk factors that are seen as common for cancer and diabetes. For this, quitting smoking and alcohol, exercising regularly and eating a healthy diet are very important. It is necessary to consume foods rich in whole grains, low in fat, protein foods and plenty of vegetables and fruits. Processed meat and similar products, high-calorie and sugary foods should be avoided.
Cancer screening may go unnoticed in diabetic people as attention is focused on diabetes treatment and related problems. Like normal healthy individuals, diabetic people should screen for cancer. Because the tumor detected in the early stages increases the chance of completely curing the disease. For this reason, it is recommended for a diabetic patient to have a colonoscopy for colon cancer screening from the age of 50, and to have mammography for breast cancer screening and pap-smear test for cervical cancer screening in female patients. Since the relationship between pancreatic cancer and diabetes is clearly known, pancreatic cancer screening should be performed in an advanced age-onset diabetic patient without a familial history of diabetes.
In various observational and experimental diabetes studies, it has been observed that some diabetic drugs cause a decrease in the frequency of cancer. For example, it has been observed that metformin, which is used very often, reduces the proliferation of cancerous cells by breaking insulin resistance and therefore reducing the need for insulin. It has been observed that the risk of pancreatic, liver, lung, colorectal and breast cancers is reduced in diabetic patients using this drug. On the other hand, there are some studies showing that the use of very high amounts of insulin leads to proliferation in cancerous cells. For this reason, it is important to give insulin as much as necessary.
Is it possible to fight and stop diabetes without cancer?
With current treatments, it is not possible to completely reset the cancer risk in diabetic patients. However, the risk can be significantly reduced by eliminating common risk factors, maintaining a balanced and healthy diet, ideal weight, and regular cancer screening.
The relationship between cancer and diabetes is very complex and it will be important to elucidate this. It will be important to clarify whether these two diseases are caused by a cause-effect relationship or due to the same risk factors, as a result of scientific studies that can be done in the future, and to develop treatments.
What are the treatment methods?
Cancer treatment in diabetic patients is not different from non-diabetic patients. Diabetic patients undergoing cancer treatment should be careful about certain drugs used in cancer treatment. For example, cortisone group drugs used as adjunctive therapy cause serious increases in blood sugar levels. It is important for diabetic patients who are obligated to use this drug group to have strict blood sugar monitoring and, if necessary, to regulate their diabetic medications under the supervision of their doctor. Injection therapy, called androgen suppression therapy, performed at intervals of 3 and 6 months in patients with prostate cancer can lead to insulin resistance and various metabolic disorders. It is appropriate for these patients to have regular blood sugar and cholesterol/triglyceride monitoring. Because both tamoxifen and diabetes increase the risk of uterine cancer in diabetic breast cancer patients using tamoxifen, it is important for this patient group to have regular gynecological examinations at least once a year.