Diabetes may worsen breast cancer outcomes

Women who have been diagnosed with breast cancer may be up to 50 percent more likely to die from any cause if they also have type 1 or type 2 diabetes, according to a new investigation from Johns Hopkins University researchers.

Investigators said that their findings show that insulin levels may play a significant role in tumor growth. They believe that future studies should focus on this area, as it may lead to improved treatments that target this possible mechanism.

For the study, which was published in the Journal of Clinical Oncology, the investigation team reviewed the findings of eight previous studies involving breast cancer and diabetes. In all investigations, they noted a strong association between the two conditions and the risk of death. In all, they found that women with both diseases were just below 50 percent more likely to die during the study period.

Kimberly Peairs, who led the study, said that when women who have diabetes receive a positive cancer diagnosis, that disease tends to be made a higher priority than their metabolic condition. This may contribute to unchecked insulin levels, which can have a range of negative health effects that increase the risk of death.

"When patients are faced with a diagnosis of breast cancer, which they see as an imminent threat to their lives, diabetes care often goes on the back burner," she said. "This research suggests we may need to proactively treat the diabetes as well as the cancer."

She said that the findings also beg the question of insulin's role in tumor growth. She said that future studies should be conducted to clarify this potential link.