Insulin resistance, usually associated with type 2 diabetes, has been shown to affect cancer patients and may cause cancer to spread more rapidly.
Researchers from the University of Copenhagen showed that patients diagnosed with cancer were markedly resistant to insulin, which can lead to metabolic dysfunction and reduced overall survival rates.
This study is the first to compile research investigating insulin resistance in cancer patients and has been published in Acta Oncologica.
The researchers hope their findings will encourage healthcare professionals to check patients’ blood sugar levels more often, even if they appear normal.
The development of insulin resistance means that the body will start producing more insulin to maintain healthy blood sugar levels. Elevated insulin levels can disrupt the body’s metabolic processes, leading to weight gain and conditions such as high blood pressure and hardening of the arteries. In cancer patients, metabolic dysfunction is common and is associated with higher cancer recurrence rates and reduced overall survival. However, insulin resistance is rarely considered in cancer care.
The researchers conducted a meta-analysis of 15 studies of insulin sensitivity and cancer, including work from MEDLINE, Embase, and Cochrane Central Register of Controlled Trials, from the inception of studies to March 2023. The analysis included 187 patients suffering from different cancer types and 154 control subjects, all over 18 years of age. The researchers only included studies that used the gold standard of measuring insulin sensitivity, known as the hyperinsulinemic-euglycemic clamp method, which is a very accurate way of analysing insulin sensitivity.
The findings showed that the insulin-stimulated glucose disposal rate was over a third lower in the cancer subjects compared to the cancer patients, indicating a higher level of insulin resistance in cancer patients.
Joan Màrmol, from the University of Copenhagen and lead author of the study, said: ‘We know from cell studies, animal studies, and some human studies that insulin is a growth hormone and that it has the same effect on cancer cells. That is, a high level of insulin can make cancer cells grow faster. Of course, this can be a huge problem for cancer patients.’
Associate Professor Lykke Sylow, also from the University of Copenhagen, added: ‘The next step is trying to determine who develops insulin resistance. Which cancer patients are at risk here? Do they have a particular type of cancer or specific risk factors? We are able to treat insulin resistance because we have in-depth knowledge of the condition – we are just used to associating it with type 2 diabetes.’
Once it is possible to identify which cancer patients will be at the highest risk of insulin resistance, the researchers hope to see more long-term studies looking into insulin resistance treatment and the impact it will have on people with a cancer diagnosis.