Consultants' claims to GP quality pay 'laughable'
Putting type 2 diabetes patients on insulin more than doubles their risk of colorectal cancer, reveals an analysis of the UK general practice research database.
The study, which analysed the records of 25,000 type 2 diabetes patients, found the risk rose by 21 per cent for every year of insulin use.
Government advisers will examine the data urgently to decide whether patients with type 2 diabetes should be screened more frequently when the national colorectal cancer screening programme is launched.
But GP experts said there was no need to discontinue or withhold insulin therapy as the benefits in patients with uncontrolled diabetes far outweighed the risk.
The incidence of colorectal cancer in type 2 diabetics was 197 per 100,000 person years in those who were taking insulin compared with 124 per 100,000 person years in those who were not.
After adjusting for age and sex, the risk of colorectal cancer was 2.1 times higher in those who had taken insulin for a year or more compared with those who had never
taken it, according to results published in Gastroenterology (October).
Study leader Dr Yu-Xiao Yang, senior lecturer in clinical epidemiology at the University of Pennsylvania, said a lower threshold may be needed for referring insulin users for colorectal cancer screening.
Professor Greg Rubin, professor of general practice at the University of Sunderland and secretary of the Primary Care Society for Gastroenterology, said: 'The increased risk from this data is only seven new
cases per 10,000 diabetics per year. Set that against the likely morbidity and mortality if
patients are not transferred to insulin.
'Transfer to insulin isn't usually optional but is done because diabetes is not controlled on oral therapy.'
Professor Kay-Tee Khaw, professor of gerontology at the University of Cambridge who led an MRC study that showed diabetics were up to three times more likely to develop colorectal cancer said: 'Both diabetes and bowel cancer share common predisposing factors. It is already accepted that a high-fibre diet and regular exercise can help protect against both diseases. Alternatively, hormonal changes associated with diabetes could promote tumour risk.'
A Department of Health spokesman said the Bowel Cancer Screening Group would consider the new research at its next meeting.
By Brian Kelly