New-onset diabetes as a signal of pancreatic cancer (and the ENDPAC score)

The link runs both ways. Long-standing type 2 diabetes raises pancreatic cancer risk about 1.8- to 1.9-fold (Huxley 2005; Ben 2011), but the association is strongest in the first years after diabetes is diagnosed (odds ratio 2.1 for diabetes of under four years against 1.5 for five years or more, Huxley 2005), which is the tumour causing the diabetes rather than the reverse. In 512 newly diagnosed patients with pancreatic cancer, 47 percent had diabetes against 7 percent of age-matched controls, much of it new-onset, and it often resolved after the cancer was removed, so the tumour is diabetogenic (Pannala 2008); in a primary care cohort 47 percent of 111 patients had diabetes, 58 percent of it new-onset, and in 80 percent of those the diabetes began while the cancer was asymptomatic, a median of 6.5 months before diagnosis, while about a third of the new diabetes went undiagnosed (Aggarwal 2012). In 2,122 Rochester residents aged 50 or over who first met criteria for diabetes, 18 (0.85 percent, about 1 percent) were diagnosed with pancreatic cancer within three years, several times the expected rate (Chari 2005). One percent is too low to scan everyone, so the ENDPAC score (Enriching New-Onset Diabetes for Pancreatic Cancer) weights change in weight, change in blood glucose and age at onset: a score of 3 or more identified patients who developed cancer within three years with 80 percent sensitivity and specificity in the discovery cohort and 78 percent sensitivity and 85 percent specificity in validation, where cancer prevalence in the high-score group was 3.6 percent (Sharma 2018). NICE NG12 (1.2.5) lists new-onset diabetes with weight loss at 60 or over among the triggers for an urgent direct-access CT, and Cancer Research UK's symptoms page names new diabetes, or diabetes diagnosed within the previous year, as a sign. Cohort studies of new-onset diabetes with blood banking, and the ideas on this site that pair the signal with multi-cancer blood tests or continuous glucose monitoring, are trying to turn the window of about six months into earlier diagnoses. Living with the diabetes once the cancer is diagnosed (type 3c diabetes, its treatment and the diabetes team) is a separate glossary term.