SHIP researchers challenge cancer scare

Many people with diabetes need insulin injections to stay healthy and natural human insulin has been safely used for decades. But recently concern has been raised about a new, synthetic form of insulin called insulin glargine (or Lantus insulin). A German study suggested a possible link between use of insulin glargine and increased cancer risk. So SHIP researchers led by Prof Helen Colhoun set out to determine whether patients taking insulin glargine have a greater cancer risk than those on other types of insulin.

The team used the Scottish Care Information-Diabetes Collaboration (SCI-DC), a clinical diabetes database that covers the majority of the Scottish population with diagnosed diabetes, to find the records of people who had had any insulin therapy. They looked at the four years since insulin glargine was introduced. The relevant records were linked to cancer registry data. The linkage was carried out by the NHS and researchers only have access to anonymised data.

They compared people taking insulin glargine only, insulin glargine with other insulins and other insulins only. The incidence of all cancers and cancers at specific sites (breast, colon, prostate, pancreas, lung) was compared among the three groups.

Overall, there was no difference in cancer incidence between those receiving any insulin glargine and those not receiving insulin glargine. But it does seem that there are more cases of cancer in general and breast cancer in particular, among people who take insulin glargine only. These data are likely to be explained by prior differences between patients who take insulin glargine alone versus those who don't rather than to be due to the insulin glargine itself.  Nonetheless the data warrant further inquiry and a larger European wide study is underway at present.

The team will now carry out a fuller analysis of cancer rates across all patients with diabetes compared with the general population.